A continuación puedes leer algunos artículos científicos sobre distintas áreas:

TREATMENT OF ACCOMMODATIVE DYSFUNCTION IN CHILDREN: RESULTS FROM A RANDOMIZED CLINICAL TRIAL.

Abstract

PURPOSE:

To report the effectiveness of various forms of vision therapy/orthoptics in improving accommodative amplitude and facility in children with symptomatic convergence insufficiency (CI) and co-existing accommodative dysfunction.

METHODS:

In a randomized clinical trial, 221 children aged 9 to 17 years with symptomatic CI were assigned to one of four treatments. Of the enrolled children, 164 (74%) had accommodative dysfunction; 63 (29%) had a decreased amplitude of accommodation with respect to age, 43 (19%) had decreased accommodative facility, and 58 (26%) had both. Analysis of variance models were used to compare mean accommodative amplitude and accommodative facility for each treatment group after 4, 8, and 12 weeks of treatment.

RESULTS:

After 12 weeks of treatment, the increases in amplitude of accommodation [office-based vergence/accommodative therapy with home reinforcement group (OBVAT) 9.9 D, home-based computer vergence/accommodative therapy group (HBCVAT+) 6.7 D, and home-based pencil push-up therapy group (HBPP) 5.8 D] were significantly greater than in the office-based placebo therapy (OBPT) group (2.2 D) (p-values ≤0.010). Significant increases in accommodative facility were found in all groups (OBVAT: 9 cpm, HBCVAT+: 7 cpm, HBPP: 5 cpm, OBPT: 5.5 cpm); only the improvement in the OBVAT group was significantly greater than that found in the OBPT group (p = 0.016). One year after completion of therapy, reoccurrence of decreased accommodative amplitude was present in only 12.5% and accommodative facility in only 11%.

CONCLUSIONS:

Vision therapy/orthoptics is effective in improving accommodative amplitude and accommodative facility in school-aged children with symptomatic CI and accommodative dysfunction.

EFFECT OF VISION THERAPY ON ACCOMMODATION IN MYOPIC CHINESE CHILDREN.

Abstract

Introduction. We evaluated the effectiveness of office-based accommodative/vergence therapy (OBAVT) with home reinforcement to improve accommodative function in myopic children with poor accommodative response. Methods. This was a prospective unmasked pilot study. 14 Chinese myopic children aged 8 to 12 years with at least 1 D of lag of accommodation were enrolled. All subjects received 12 weeks of 60-minute office-based accommodative/vergence therapy (OBAVT) with home reinforcement. Primary outcome measure was the change in monocular lag of accommodation from baseline visit to 12-week visit measured by Shinnipon open-field autorefractor. Secondary outcome measures were the changes in accommodative amplitude and monocular accommodative facility. Results. All participants completed the study. The lag of accommodation at baseline visit was 1.29 ± 0.21 D and it was reduced to 0.84 ± 0.19 D at 12-week visit. This difference (-0.46 ± 0.22 D; 95% confidence interval: -0.33 to -0.58 D) is statistically significant (p < 0.0001). OBAVT also increased the amplitude and facility by 3.66 ± 3.36 D (p = 0.0013; 95% confidence interval: 1.72 to 5.60 D) and 10.9 ± 4.8 cpm (p < 0.0001; 95% confidence interval: 8.1 to 13.6 cpm), respectively. Conclusion. Standardized 12 weeks of OBAVT with home reinforcement is able to significantly reduce monocular lag of accommodation and increase monocular accommodative amplitude and facility. A randomized clinical trial designed to investigate the effect of vision therapy on myopia progression is warranted.

EFFECT OF VISION THERAPY ON ACCOMODATIVE LAG IN MYOPIC CHILDREN: A RANDOMIZED CLINICAL TRIAL.

Abstract

SIGNIFICANCE:

Accommodative dysfunction has been suggested to be related to the development and progression of myopia. Office-based accommodative/vergence therapy (OBAVT) improved accommodative facility in Chinese myopic children, but it is unclear if such improvement has a role in decreasing myopic progression.

PURPOSE:

The purpose of this study was to compare the effects of OBAVT with home reinforcement and office-based placebo therapy (OBPT) as a treatment to improve accommodative functions (i.e., lag, amplitude, and facility) in myopic children with poor accommodative accuracy.

METHODS:

This was a prospective, single-masked, randomized clinical trial. Thirty-four Chinese children 8 to 12 years old with myopia and at least 1 diopter of lag of accommodation measured by autorefraction were enrolled. The participants were randomly assigned to the OBAVT or OBPT group. The primary outcome measure was the change in the monocular lag of accommodation from the baseline visit to the 13-week visit measured by a Shin-Nippon open-field autorefractor. Secondary outcome measures were changes in accommodative amplitude and monocular accommodative facility.

RESULTS:

A total of 33 participants completed the study. After 12 weeks of treatment, there were significant improvements in the lag of accommodation in both the OBAVT and OBPT groups (OBAVT: -0.30 ± 0.29 diopters [P < .001; Cohen’s d effect size, 1.29]; OBPT: -0.24 ± 0.30 diopters [P = .005; Cohen’s d effect size, 1.24]). There was no statistically significant difference between the improvements in the two groups (P = .50). There was statistically significant improvement in monocular accommodative facility only in the OBAVT group (OBAVT: 7.7 ± 4.7 cycles per minute [P < .001; Cohen’s d effect size, 2.20]; OBPT: 1.9 ± 4.4 cycles per minute [P = .072]). The change in the OBAVT group was statistically significantly larger than that in the OBPT group (P < .001).

CONCLUSIONS:

Office-based accommodative/vergence therapy was no more effective than OBPT in reducing the lag of accommodation in children 8 to 12 years old with low to moderate myopia. It did improve accommodative facility in Chinese myopic children, but it is unclear if such an improvement has a role in decreasing myopic progression.

THE SCIENTIFIC BASIS FOR AND EFFICACY OF OPTOMETRIC VISION THERAPY IN NONSTRABISMIC ACCOMMODATIVE AND VERGENCE DISORDERS.

Abstract

BACKGROUND:

For nearly 75 years, optometric vision therapy has been an important mode of therapy for both children and adults who manifested a range of nonstrabismic accommodative and vergence disorders.

METHODS:

In this article, the scientific basis for, and efficacy of, optometric vision therapy in such patients will be discussed. Using bio-engineering models of the oculomotor system as the conceptual framework, emphasis will be focused on studies that used objective recording techniques to directly assess therapeutically related changes in oculomotor responsivity.

RESULTS AND CONCLUSIONS:

The findings clearly support the validity of optometric vision therapy. Furthermore, the results are consistent with the tenets of general motor learning.

ACCOMMODATIVE FACILITY TRAINING WITH A LONG TERM FOLLOW UP IN A SAMPLE OF SCHOOL AGED CHILDREN SHOWING ACCOMMODATIVE DYSFUNCTION.

Abstract

The primary aim of this project was to study the effect of flip lens-training on the accommodative function in a group of children with accommodative dysfunction and subjective symptoms such as asthenopia, headache, blurred vision, and avoidance of near activity. We also wanted to measure the accommodative facility among the children in comparison with a control group. Another aim of the study was whether flip lens-training increased accommodative facility, and to find out if it also had a positive effect on their asthenopia and related problems also in long term. Following the training period the accommodative facility and accommodative function significantly increased and two years after finishing the training period no child had regained any subjective symptoms and the objective findings were almost the same as at the end of facility training period. These results suggest that accommodative facility training is an efficient method built on loss of symptoms among children with accommodative infacility.

THE EFFECTS OF ACCOMMODATIVE FACILITY TRAINING ON A GROUP OF CHILDREN WITH IMPAIRED RELATIVE ACCOMMODATION–A COMPARISON BETWEEN DIOPTRIC TREATMENT AND SHAM TREATMENT.

Abstract

The effects of accommodative facility training were evaluated by comparing training with plano lenses and +/-2.00 D lens flipper sets. Thirteen children with symptoms and signs of accommodative dysfunction were included in the study. Seven started with 2 weeks of plano lens training before proceeding to traditional dioptric flipper training; later, one patient from this group was lost to follow-up. The remaining six children used powered flipper training from the start. The positive (PRA) and negative relative accommodation (NRA) were examined every second week. During the initial training period both the PRA and the NRA decreased in the sham treatment group (P = 0.010 and P= 0.102, respectively), while the PRA and the NRA increased during the dioptric training in both groups (P = 0.102 and P = 0.033, respectively). The result of this study indicates that accommodative facility training has a real effect on the amplitude of relative accommodation in patients with impaired relative accommodation.

EFFECT OF OCULOMOTOR REHABILITATION ON ACCOMODATIVE RESPOSIVITY IN MILD TRAUMATIC BRAIN INJURY.

Abstract

Accommodative dysfunction is a common oculomotor sequelae of mild traumatic brain injury (mTBI). This study evaluated a range of dynamic (objective) and static (subjective) measures of accommodation in 12 nonstrabismic individuals with mTBI and near vision-related symptoms before and after oculomotor training (OMT) and placebo (P) training (6 wk, two sessions per week, 3 h of training each). Following OMT, the dynamics of accommodation improved markedly. Clinically, there was a significant increase in the maximum accommodative amplitude both monocularly and binocularly. In addition, the near vision symptoms reduced along with improved visual attention. None of the measures were found to change significantly following P training. These results provide evidence for a significant positive effect of the accommodatively based OMT on accommodative responsivity. Such improvement is suggestive of oculomotor learning, demonstrating considerable residual brain-visual system plasticity in the adult compromised brain.

VISUAL TRAINING IMPROVES UNDERWATER VISION IN CHILDREN.

Abstract

Children in a tribe of sea-gypsies from South-East Asia have been found to have superior underwater vision compared to European children. In this study, we show that the improved underwater vision of these Moken children is not due to better contrast sensitivity in general. We also show that European children can achieve the same underwater acuity as the Moken children. After 1 month of underwater training (11 sessions) followed by 4 months with no underwater activities, European children showed improved underwater vision and distinct bursts of pupil constriction. When tested 8 months after the last training session in an outdoor pool in bright sunlight-comparable to light environments in South-East Asia-the children had attained the same underwater acuity as the sea-gypsy children. The achieved performance can be explained by the combined effect of pupil constriction and strong accommodation.

RANDOMIZED CLINICAL TRIAL OF TREATMENTS FOR SYMPTOMATIC CONVERGENCE INSUFFICIENCY IN CHILDREN.

Abstract

OBJECTIVE:

To compare home-based pencil push-ups (HBPP), home-based computer vergence/accommodative therapy and pencil push-ups (HBCVAT+), office-based vergence/accommodative therapy with home reinforcement (OBVAT), and office-based placebo therapy with home reinforcement (OBPT) as treatments for symptomatic convergence insufficiency.

METHODS:

In a randomized clinical trial, 221 children aged 9 to 17 years with symptomatic convergence insufficiency were assigned to 1 of 4 treatments.

MAIN OUTCOME MEASURES:

Convergence Insufficiency Symptom Survey score after 12 weeks of treatment. Secondary outcomes were near point of convergence and positive fusional vergence at near.

RESULTS:

After 12 weeks of treatment, the OBVAT group’s mean Convergence Insufficiency Symptom Survey score (15.1) was statistically significantly lower than those of 21.3, 24.7, and 21.9 in the HBCVAT+, HBPP, and OBPT groups, respectively (P < .001). The OBVAT group also demonstrated a significantly improved near point of convergence and positive fusional vergence at near compared with the other groups (P <or= .005 for all comparisons). A successful or improved outcome was found in 73%, 43%, 33%, and 35% of patients in the OBVAT, HBPP, HBCVAT+, and OBPT groups, respectively.

CONCLUSIONS:

Twelve weeks of OBVAT results in a significantly greater improvement in symptoms and clinical measures of near point of convergence and positive fusional vergence and a greater percentage of patients reaching the predetermined criteria of success compared with HBPP, HBCVAT+, and OBPT. Application to Clinical Practice Office-based vergence accommodative therapy is an effective treatment for children with symptomatic convergence insufficiency.

A RANDOMIZED CLINICAL TRIAL OF TREATMENTS FOR CONVERGENCE INSUFFICIENCY IN CHILDREN.

Abstract

OBJECTIVE:

To compare vision therapy/orthoptics, pencil push-ups, and placebo vision therapy/orthoptics as treatments for symptomatic convergence insufficiency in children 9 to 18 years of age.

METHODS:

In a randomized, multicenter clinical trial, 47 children 9 to 18 years of age with symptomatic convergence insufficiency were randomly assigned to receive 12 weeks of office-based vision therapy/orthoptics, office-based placebo vision therapy/orthoptics, or home-based pencil push-ups therapy.

MAIN OUTCOME MEASURES:

The primary outcome measure was the symptom score on the Convergence Insufficiency Symptom Survey. Secondary outcome measures were the near point of convergence and positive fusional vergence at near.

RESULTS:

Symptoms, which were similar in all groups at baseline, were significantly reduced in the vision therapy/orthoptics group (mean symptom score decreased from 32.1 to 9.5) but not in the pencil push-ups (mean symptom score decreased from 29.3 to 25.9) or placebo vision therapy/orthoptics groups (mean symptom score decreased from 30.7 to 24.2). Only patients in the vision therapy/orthoptics group demonstrated both statistically and clinically significant changes in the clinical measures of near point of convergence (from 13.7 cm to 4.5 cm; P < .001) and positive fusional vergence at near (from 12.5 prism diopters to 31.8 prism diopters; P < .001).

CONCLUSIONS:

In this pilot study, vision therapy/orthoptics was more effective than pencil push-ups or placebo vision therapy/orthoptics in reducing symptoms and improving signs of convergence insufficiency in children 9 to 18 years of age. Neither pencil push-ups nor placebo vision therapy/orthoptics was effective in improving either symptoms or signs associated with convergence insufficiency.

A RANDOMIZED CLINICAL TRIAL OF VISION THERAPY/ORTHOPTICS VERSUS PENCIL PUSHUPS FOR THE TREATMENT OF CONVERGENCE INSUFFICIENCY IN YOUNG ADULTS.

Abstract

PURPOSE:

The purpose of this article is to compare vision therapy/orthoptics, pencil pushups, and placebo vision therapy/orthoptics as treatments for symptomatic convergence insufficiency in adults 19 to 30 years of age.

METHODS:

In a randomized, multicenter clinical trial, 46 adults 19 to 30 years of age with symptomatic convergence insufficiency were randomly assigned to receive 12 weeks of office-based vision therapy/orthoptics, office-based placebo vision therapy/orthoptics, or home-based pencil pushups. The primary outcome measure was the symptom score on the Convergence Insufficiency Symptom Survey. Secondary outcome measures were the near point of convergence and positive fusional vergence at near.

RESULTS:

Only patients in the vision therapy/orthoptics group demonstrated statistically and clinically significant changes in the near point of convergence (12.8 cm to 5.3 cm, p = 0.002) and positive fusional vergence at near (11.3Delta to 29.7Delta, p = 0.001). Patients in all three treatment arms demonstrated statistically significant improvement in symptoms with 42% in office-based vision therapy/orthoptics, 31% in office-based placebo vision therapy/orthoptics, and 20% in home-based pencil pushups achieving a score <21 (our predetermined criteria for elimination of symptoms) at the 12-week visit.

DISCUSSION:

In this study, vision therapy/orthoptics was the only treatment that produced clinically significant improvements in the near point of convergence and positive fusional vergence. However, over half of the patients in this group (58%) were still symptomatic at the end of treatment, although their symptoms were significantly reduced. All three groups demonstrated statistically significant changes in symptoms with 42% in office-based vision therapy/orthoptics, 31% in office-based placebo vision therapy/orthoptics, and 20% in home-based pencil push-ups meeting our criteria for elimination of symptoms.

NON-SURGICAL INTERVENTIONS FOR CONVERGENCE INSUFFICIENCY.

Abstract

BACKGROUND:

Convergence insufficiency is a common eye muscle co-ordination problem in which the eyes have a strong tendency to drift outward (exophoria) when reading or doing close work. Symptoms may include eye strain, headaches, double vision, print moving on the page, frequent loss of place when reading, inability to concentrate, and short attention span.

OBJECTIVES:

To systematically assess and synthesize evidence from randomized controlled trials (RCTs) on the effectiveness of non-surgical interventions for convergence insufficiency.

SEARCH STRATEGY:

We searched The Cochrane Library, MEDLINE, EMBASE, Science Citation Index, the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com) and ClinicalTrials.gov (www.clinicaltrials.gov ) on 7 October 2010. We manually searched reference lists and optometric journals.

SELECTION CRITERIA:

We included RCTs examining any form of non-surgical intervention against placebo, no treatment, sham treatment, or each other.

DATA COLLECTION AND ANALYSIS:

Two authors independently assessed eligibility, risk of bias, and extracted data. We performed meta-analyses when appropriate.

MAIN RESULTS:

We included six trials (three in children, three in adults) with a total of 475 participants. We graded four trials at low risk of bias.Evidence from one trial (graded at low risk of bias) suggests that base-in prism reading glasses was no more effective than placebo reading glasses in improving clinical signs or symptoms in children. Evidence from one trial (graded at high risk of bias) suggests that base-in prism glasses using a progressive addition lens design was more effective than progressive addition lens alone in decreasing symptoms in adults. At three weeks of therapy, the mean difference in Convergence Insufficiency Symptoms Survey (CISS) score was -10.24 points (95% confidence interval (CI) -15.45 to -5.03). Evidence from two trials (graded at low risk of bias) suggests that outpatient (or office-based as used in the US) vision therapy/orthoptics was more effective than home-based convergence exercises (or pencil push-ups as used in the US) in children. At 12 weeks of therapy, the mean difference in change in near point of convergence, positive fusional vergence, and CISS score from baseline was 3.99 cm (95% CI 2.11 to 5.86), 13.13 diopters (95% CI 9.91 to 16.35), and 9.86 points (95% CI 6.70 to 13.02), respectively.In a young adult population, evidence from one trial (graded at low risk of bias) suggests outpatient vision therapy/orthoptics was more effective than home-based convergence exercises in improving positive fusional vergence at near (7.7 diopters, 95% CI 0.82 to 14.58), but not the other outcomes.Evidence from one trial (graded at low risk of bias) comparing four interventions, also suggests that outpatient vision therapy/orthoptics was more effective than home-based computer vision therapy/orthoptics in children. At 12 weeks, the mean difference in change in near point of convergence, positive fusional vergence, and CISS score from baseline was 2.90 cm (95% CI 0.96 to 4.84), 7.70 diopters (95% CI 3.94 to 11.46), and 8.80 points (95% CI 5.26 to 12.34), respectively. Evidence was less consistent for other pair-wise comparisons.

AUTHORS’ CONCLUSIONS:

Current research suggests that outpatient vision therapy/orthoptics is more effective than home-based convergence exercises or home-based computer vision therapy/orthoptics for children. In adult population, evidence of the effectiveness of various non-surgical interventions is less consistent.

IMPROVEMENT IN ACADEMIC BEHAVIORS AFTER SUCCESSFUL TREATMENT OF CONVERGENCE INSUFFICIENCY.

Abstract

PURPOSE:

To determine whether treatment of symptomatic convergence insufficiency (CI) has an effect on Academic Behavior Survey (ABS) scores.

METHODS:

The ABS is a six-item survey developed by the Convergence Insufficiency Treatment Trial Group that quantifies the frequency of adverse school behaviors and parental concern about school performance on an ordinal scale from 0 (never) to 4 (always) with total scores ranging from 0 to 24. The ABS was administered at baseline and after 12 weeks of treatment to the parents of 218 children aged 9 to 17 years with symptomatic CI, who were enrolled in the Convergence Insufficiency Treatment Trial and randomized into (1) home-based pencil push-ups; (2) home-based computer vergence/accommodative therapy and pencil push-ups; (3) office-based vergence/accommodative therapy with home reinforcement; and (4) office-based placebo therapy with home reinforcement. Participants were classified as successful (n = 42), improved (n = 60), or non-responder (n = 116) at the completion of 12 weeks of treatment using a composite measure of the symptom score, nearpoint of convergence, and positive fusional vergence. Analysis of covariance methods were used to compare the mean change in ABS between response to treatment groups while controlling for the ABS score at baseline.

RESULTS:

The mean ABS score for the entire group at baseline was 12.85 (SD = 6.3). The mean ABS score decreased (improved) in those categorized as successful, improved, and non-responder by 4.0, 2.9, and 1.3 points, respectively. The improvement in the ABS score was significantly related to treatment outcome (p < 0.0001), with the ABS score being significantly lower (better) for children who were successful or improved after treatment as compared to children who were non-responders (p = 0.002 and 0.043, respectively).

CONCLUSIONS:

A successful or improved outcome after CI treatment was associated with a reduction in the frequency of adverse academic behaviors and parental concern associated with reading and school work as reported by parents.

EFFECTIVENESS OF VISION THERAPY IN SCHOOL CHILDREN WITH SYMPTOMATIC CONVERGENCE INSUFFICIENCY.

Abstract

PURPOSE:

To determine the effectiveness of vision therapy among Korean elementary school children with convergence insufficiency.

METHODS:

A total of 235 elementary schoolchildren, 10.13 ± 2.45 years of age, were subjected to thorough eye examination including binocular vision testing. Of them, 32 individuals with symptomatic convergence insufficiency without strabismus, amblyopia, and ocular disease were chosen to receive vision therapy via brock string, barrel card, mirror stereoscope, prism goggles, and aperture rule for a duration of 8 weeks.

RESULTS:

The results showed that most of the participants had severe problems in near point of convergence. After the vision therapy, the average near point of convergence improved by approximately 5.48 ± 0.96 cm in all participants. Moreover, vision therapy had an effect on increasing near positive fusional vergence and decreasing exophoria. Negative relative accommodation improved to 2.54 ± 0.51 and positive relative accommodation improved to -3.10 ± 1.08 diopters. After treatment, near phoria was 4.19 ± 1.66 and distance phoria was 1.61 ± 0.71 prism diopters.

CONCLUSION:

Among convergence insufficiency symptoms, the following improved in particular: near point of convergence, exophoria, and near positive fusional vergence. These findings suggest that vision therapy is very effective to recover from symptomatic convergence insufficiency.

OBJECTIVE ASSESSMENT OF DISPARITY VERGENCE AFTER TREATMENT OF SYMPTOMATIC CONVERGENCE INSUFFICIENCY IN CHILDREN.

Abstract

SIGNIFICANCE:

This first report of the use of objective measures of disparity vergence as outcome measures for symptomatic convergence insufficiency in children provides additional information that is not accessible with clinical tests. The study results also demonstrate that objective measures of vergence could be used in future randomized clinical trials of binocular vision disorders with children.

PURPOSE:

This study was designed to evaluate changes in objective measures of disparity vergence after office-based vergence/accommodative therapy (OBVAT) for convergence insufficiency in children 12 to 17 years old.

METHODS:

In this prospective trial, we recruited 10 participants with normal binocular vision and 12 with convergence insufficiency. All participants with convergence insufficiency were treated with 12 weeks of OBVAT. The primary outcome measure was average peak velocity for 4° symmetrical convergence steps. Other objective outcome measures of disparity vergence included time to peak velocity, latency, and accuracy. Changes in clinical measures (near point of convergence, positive fusional vergence at near) and symptoms were evaluated.

RESULTS:

There was a statistically significant increase in peak velocity and more accurate response amplitude to 4° symmetrical convergence step stimuli after OBVAT compared with baseline measurements. Near point of convergence, positive fusional vergence, and symptoms also statistically significantly improved after OBVAT. Ten of the 12 participants met clinical success criteria.

CONCLUSIONS:

In this prospective study on the treatment of symptomatic convergence insufficiency in children in which both clinical and objective eye movement measurements were used to evaluate the results of treatment, significant changes were found in symptoms and both clinical and objective measures of disparity vergence after completion of OBVAT in children with symptomatic convergence insufficiency.

EFFICACY OF TREATMENT FOR CONVERGENCE INSUFFICIENCY USING VISION THERAPY.

Abstract

PURPOSE:

The purpose of this study was to determine if vision therapy (VT), as practised within the constraints of UK optometric practice, employing graded routine eye exercises, is as an effective method for treatment of convergence insufficiency (CI) as previously published data suggest. The study also evaluates the associated symptoms before and after therapy.

METHODS:

As many optometrists diagnose CI solely on the basis of near point of convergence (NPC) and treat only when symptoms are present (Letourneau et al., 1979; Rouse et al., 1997), in this study CI was defined as NPC of 10 cm or greater (either with or without the presence of asthenopic symptoms for near work) accompanied by exophoria greater at near than at distance. The effect of treatment by optometric vision therapy (OVT) on the NPC and number of symptoms was investigated for 92 patients by retrospectively reviewing the clinical records. Success was defined as the restoration of NPC to normal values and significant reduction in the presenting symptoms.

RESULTS:

The effect of treatment on the NPC was shown to be highly significant (t = 14.61, p < 0.001). Although treatment times were slightly longer, the success rates were higher than reported by other authors. Post-treatment values for NPC were: <10 cm (98.9%), <8.5 cm (95.7%) and <6.5 cm (80.4%). Longer treatment times were noted for patients who complained that the text appeared to move (chi2, p = 0.007).

CONCLUSION:

Vision therapy is an effective method for treatment of CI.

A PILOT STUDY OF DISPARITY VERGENCE AND NEAR DISSOCIATED PHORIA IN CONVERGENCE INSUFFICIENCY PATIENTS BEFORE VS. AFTER VERGENCE THERAPY.

Abstract

PURPOSE:

This study examined the relationship between the near dissociated phoria and disparity vergence eye movements. Convergence insufficiency (CI) patients before vergence therapy were compared to: (1) the same patients after vergence therapy; and (2) binocularly normal controls (BNC).

METHODS:

Sixteen subjects were studied-twelve BNC and four with CI. Measurements from the CI subjects were obtained before and after 18 h of vergence eye movement therapy. The near dissociated phoria was measured using the flashed Maddox rod technique. Vergence responses were stimulated from 4° symmetrical disparity vergence step stimuli. The peak velocity of the vergence response and the magnitude of the fusion initiating component (FIC) from an independent component analysis (ICA) were calculated. A linear regression analysis was conducted studying the vergence peak velocity as a function of the near dissociated phoria where the Pearson correlation coefficient was computed.

RESULTS:

Before vergence therapy, the average with one standard deviation FIC magnitude of convergence responses from CI subjects was 0.29° ± 0.82 and significantly less than the FIC magnitude of 1.85° ± 0.84 for BNC (p < 0.02). A paired t-test reported that the FIC and near dissociated phoria before vergence therapy for CI subjects significantly increased to 1.49° ± 0.57 (p < 0.04) and became less exophoric to 3.5Δ ± 1.9 exo (p < 0.02) after vergence therapy. A significant correlation (r = 0.87; p < 0.01) was observed between the near dissociated phoria and the vergence ratio of convergence peak velocity divided by divergence peak velocity.

CONCLUSION:

The results have clinical translational impact in understanding the mechanism by which vergence therapy may be changing the vergence system leading to a sustained reduction in visual symptoms.

Vision therapy in adults with convergence Insufficiency: clinical and functional Magnetic resonance imaging measures.

VISION THERAPY IN ADULTS WITH CONVERGENCE INSUFFICIENCY: CLINICAL AND FUNCTIONAL MAGNETIC RESONANCE IMAGING MEASURES.

Abstract

PURPOSE:

This research quantified clinical measurements and functional neural changes associated with vision therapy in subjects with convergence insufficiency (CI).

METHODS:

Convergence and divergence 4° step responses were compared between 13 control adult subjects with normal binocular vision and four CI adult subjects. All CI subjects participated in 18 h of vision therapy. Clinical parameters quantified throughout the therapy included: nearpoint of convergence, recovery point of convergence, positive fusional vergence at near, near dissociated phoria, and eye movements that were quantified using peak velocity. Neural correlates of the CI subjects were quantified with functional magnetic resonance imaging scans comparing random vs. predictable vergence movements using a block design before and after vision therapy. Images were quantified by measuring the spatial extent of activation and the average correlation within five regions of interests (ROI). The ROIs were the dorsolateral prefrontal cortex, a portion of the frontal lobe, part of the parietal lobe, the cerebellum, and the brain stem. All measurements were repeated 4 months to 1 year post-therapy in three of the CI subjects.

RESULTS:

Convergence average peak velocities to step stimuli were significantly slower (p = 0.016) in CI subjects compared with controls; however, significant differences in average peak velocities were not observed for divergence step responses (p = 0.30). The investigation of CI subjects participating in vision therapy showed that the nearpoint of convergence, recovery point of convergence, and near dissociated phoria significantly decreased. Furthermore, the positive fusional vergence, average peak velocity from 4° convergence steps, and the amount of functional activity within the frontal areas, cerebellum, and brain stem significantly increased. Several clinical and cortical parameters were significantly correlated.

CONCLUSIONS:

Convergence peak velocity was significantly slower in CI subjects compared with controls, which may result in asthenopic complaints reported by the CI subjects. Vision therapy was associated with and may have evoked clinical and cortical activity changes.

POST-THERAPY FUNCTIONAL MAGNETIC RESONANCE IMAGING  IN ADULTS WITH SYMPTOMATIC CONVERGENCE INSUFFICIENCY.

Abstract

SIGNIFICANCE:

Prior studies have demonstrated the effectiveness of vergence-accommodative therapy in the treatment of convergence insufficiency (CI). These results show the changes in brain activation following therapy through the use of functional magnetic resonance imaging (fMRI).

PURPOSE:

The purpose of this study was to investigate changes in brain activation following office-based vergence-accommodative therapy versus placebo therapy for CI using the blood oxygenation level-dependent signal from fMRI.

METHODS:

Adults (n = 7, aged 18 to 30 years) with symptomatic CI were randomized to 12 weeks of vergence-accommodative therapy (n = 4) or placebo therapy (n = 3). Vergence eye movements were performed during baseline and outcome fMRI scans.

RESULTS:

Before therapy, activation (z score ≥ 2.3) was observed in the occipital lobe and areas of the brain devoted to attention, with the largest areas of activation found in the occipital lobe. After vergence-accommodative therapy, activation in the occipital lobe decreased in spatial extent but increased in the level of activation in the posterior, inferior portion of the occipital lobe. A new area of activation appeared in the regions of the lingual gyrus, which was not seen after placebo therapy. A significant decrease in activation was also observed in areas of the brain devoted to attention after vergence-accommodative therapy and to a lesser extent after placebo therapy.

CONCLUSIONS:

Observed activation pre-therapy consistent with top-down processing suggests that convergence requires conscious effort in symptomatic CI. Decreased activation in these areas after vergence-accommodative therapy was associated with improvements in clinical signs such as fusional vergence after vergence-accommodative therapy. The increase in blood oxygen level-dependent response in the occipital areas following vergence-accommodative therapy suggests that disparity processing for both depth and vergence may be enhanced following vergence-accommodative therapy.

EVALUATION OF BINOCULAR VISION THERAPY EFFICACY BY 3D VIDEO-OCULOGRAPHY MEASUREMENT OF BINOCULAR ALIGNMENT AND MOTILITY.

Abstract

OBJECTIVE:

To evaluate two cases of intermittent exotropia treated by vision therapy the efficacy of the treatment by complementing the clinical examination with a 3D videooculography to register and to evidence the potential applicability of this technology for such purpose.

METHODS:

We report the binocular alignment changes occurring after vision therapy in a woman of 36 years with an intermittent exotropia of 25 prism diopters at far and 18 PD at near and a child of 10 years with 8 PD of intermittent exotropia in primary position associated to 6 PD of left eye hypotropia. Both patients presented good visual acuity with correction in both eyes. Instability of ocular deviation was evident by VOG analysis, revealing also the presence of vertical and torsional components. Binocular vision therapy was prescribed and performed including different types of vergence, accommodation, and consciousness of diplopia training.

RESULTS:

After therapy, excellent ranges of fusional vergence and a to-the-nose near point of convergence were obtained.The 3D VOG examination confirmed the compensation of the deviation with a high level of stability of binocular alignment. Significant improvement could be observed after therapy in the vertical and torsional components that were found to become more stable. Patients were very satisfied with the outcome obtained by vision therapy.

CONCLUSION:

3D-VOG is a useful technique for providing an objective register of the compensation of the ocular deviation and the stability of the binocular alignment achieved after vision therapy in cases of intermittent exotropia, providing a detailed analysis of vertical and torsional improvements.

REDUCTION OF SYMPTOMS IN BINOCULAR ANOMALIES USING COMPUTERIZED HOME THERAPY-HTS.

Abstract

BACKGROUND:

Asthenopic symptoms often are associated with various accommodative/vergence disorders. Recent studies have found that symptoms associated with convergence insufficiency are reduced by in-office vision therapy with supplemental home therapy. No studies have used standardized symptom questionnaires to evaluate the effectiveness of either in-office or home-based vision therapy in binocular anomalies other than convergence insufficiency. This retrospective study was designed to evaluate the changes in symptoms using an automated, home computer vision therapy program (HTS) in accommodative/vergence disorders.

METHODS:

A retrospective study of 43 prepresbyopic patients who completed the HTS was performed. Before and immediately after treatment all patients in this study completed a 15-question symptom questionnaire (Convergence Insufficiency Symptom Survey). Treatment consisted of various accommodative and vergence activities.

RESULTS:

Initial symptoms scores on the scaled questionnaire were 32.8 (SD = 8.1); after therapy they were 20.6 (SD = 11.5). These changes were both clinically and statistically significant. Forty percent were «normalized» and 55% improved. Convergence amplitude improved from 22Delta to 53Delta after treatment, and divergence amplitudes improved from 15Delta to 25Delta. These findings were clinically significant. Lastly, more than 75% of the patients finished the program by 40 sessions (equivalent to 8 weeks).

CONCLUSION:

Automated vision therapy delivered by the HTS system improved convergence and divergence amplitudes with a concomitant reduction in symptoms. The HTS system should be used on those patients with symptoms associated with an accommodative/vergence anomaly when in-office vision therapy supplemented with home therapy is not practical.

EYE MOVEMENT TRAINING AND SUGGESTED GAZE STRATEGIES IN TUNNEL VISION – A RANDOMIZED AND CONTROLLED PILOT STUDY.

Abstract

PURPOSE:

Degenerative retinal diseases, especially retinitis pigmentosa (RP), lead to severe peripheral visual field loss (tunnel vision), which impairs mobility. The lack of peripheral information leads to fewer horizontal eye movements and, thus, diminished scanning in RP patients in a natural environment walking task. This randomized controlled study aimed to improve mobility and the dynamic visual field by applying a compensatory Exploratory Saccadic Training (EST).

METHODS:

Oculomotor responses during walking and avoiding obstacles in a controlled environment were studied before and after saccade or reading training in 25 RP patients. Eye movements were recorded using a mobile infrared eye tracker (Tobii glasses) that measured a range of spatial and temporal variables. Patients were randomly assigned to two training conditions: Saccade (experimental) and reading (control) training. All subjects who first performed reading training underwent experimental training later (waiting list control group). To assess the effect of training on subjects, we measured performance in the training task and the following outcome variables related to daily life: Response Time (RT) during exploratory saccade training, Percent Preferred Walking Speed (PPWS), the number of collisions with obstacles, eye position variability, fixation duration, and the total number of fixations including the ones in the subjects’ blind area of the visual field.

RESULTS:

In the saccade training group, RTs on average decreased, while the PPWS significantly increased. The improvement persisted, as tested 6 weeks after the end of the training. On average, the eye movement range of RP patients before and after training was similar to that of healthy observers. In both, the experimental and reading training groups, we found many fixations outside the subjects’ seeing visual field before and after training. The average fixation duration was significantly shorter after the training, but only in the experimental training condition.

CONCLUSIONS:

We conclude that the exploratory saccade training was beneficial for RP patients and resulted in shorter fixation durations after the training. We also found a significant improvement in relative walking speed during navigation in a real-world like controlled environment.

COMPARING EXPLORATIVE SACCADE AND FLICKER TRAINING IN HEMIANOPIA: A RANDOMIZED CONTROLLED STUDY.

Abstract

OBJECTIVE:

Patients with homonymous hemianopia are disabled on everyday exploratory activities. We examined whether explorative saccade training (EST), compared with flicker-stimulation training (FT), would selectively improve saccadic behavior on the patients’ blind side and benefit performance on natural exploratory tasks.

METHODS:

Twenty-eight hemianopic patients were randomly assigned to distinct groups performing for 6 weeks either EST (a digit-search task) or FT (blind-hemifield stimulation by flickering letters). Outcome variables (response times [RTs] during natural search, number of fixations during natural scene exploration, fixation stability, visual fields, and quality-of-life scores) were collected before, directly after, and 6 weeks after training.

RESULTS:

EST yielded a reduced (post/pre, 47%) digit-search RT for the blind side. Natural search RT decreased (post/pre, 23%) on the blind side but not on the seeing side. After FT, both sides’ RT remained unchanged. Only with EST did the number of fixations during natural scene exploration increase toward the blind and decrease on the seeing side (follow-up/pre difference, 238%). Even with the target located on the seeing side, after EST more fixations occurred toward the blind side. The EST group showed decreased (post/pre, 43%) fixation stability and increased (post/pre, 482%) asymmetry of fixations toward the blind side. Visual field size remained constant after both treatments. EST patients reported improvements in social domain.

CONCLUSIONS:

Explorative saccade training selectively improves saccadic behavior, natural search, and scene exploration on the blind side. Flicker-stimulation training does not improve saccadic behavior or visual fields. The findings show substantial benefits of compensatory exploration training, including subjective improvements in mastering daily-life activities, in a randomized controlled trial.

THERAPIST-ASSISTED VISION THERAPY  IMPROVES OUTCOME  FOR STROKE PATIENTS WITH HOMONYMOUS HEMIANOPIA ALONE OR COMBINED WITH OCULOMOTOR DYSFUNCTION.

Abstract

OBJECTIVE:

To improve visual performance and perception in stroke patients suffering from visual impairments by the use of therapist-assisted vision therapy.

METHODS:

This study was an interventional efficacy open-label investigation. The vision therapy was designed to enhance binocular vision, and saccadic ability, and vergence ranges maximally, and for patients with hemianopia also to improve peripheral awareness. The vision training consisted of one lesson a week for 12 weeks carried out by an optometrist and a vision therapist. Between lessons, patients were to train at home for a minimum of 15-20 min daily.

RESULTS:

Twenty-four patients completed the course. Significant improvements in visual performance were measured for all test parameters from the baseline to the evaluation after the last lesson of vision training. The COPM results improved both in terms of satisfaction with the completion of a task and with the way the task was carried out (p = 0.001). Groffman tracing test results improved from median 7.5 to 16 (p = 0.002), reading speed in words increased (p = 0.0004), and peripheral awareness of visual markers improved (p = 0.002).

CONCLUSION:

Therapist-assisted vision therapy increased peripheral visual awareness. Furthermore, patients felt safer in the traffic and in outdoor activities. Reading speed significantly increased, and the ability to keep a moving object in focus improved.

A RANDOMIZED TRIAL OF A BINOCULAR iPad GAME VERSUS PART-TIME PATCHING IN CHILDREN AGED 13 TO 16 YEARS WITH AMBLYOPIA.

Abstract

PURPOSE:

To compare visual acuity (VA) improvement in teenagers with amblyopia treated with a binocular iPad game vs part-time patching.

METHODS:

One hundred participants aged 13 to <17 years (mean 14.3 years) with amblyopia (20/40 to 20/200, mean ∼20/63) resulting from strabismus, anisometropia, or both were enrolled into a randomized clinical trial. Participants were randomly assigned to treatment for 16 weeks of either a binocular iPad game prescribed for 1 hour per day (n = 40) or patching of the fellow eye prescribed for 2 hours per day (n = 60). The main outcome measure was change in amblyopic eye VA from baseline to 16 weeks.

RESULTS:

Mean amblyopic eye VA improved from baseline by 3.5 letters (2-sided 95% confidence interval [CI]: 1.3-5.7 letters) in the binocular group and by 6.5 letters (2-sided 95% CI: 4.4-8.5 letters) in the patching group. After adjusting for baseline VA, the difference between the binocular and patching groups was -2.7 letters (95% CI: -5.7 to 0.3 letters, P = .082) or 0.5 lines, favoring patching. In the binocular group, treatment adherence data from the iPad device indicated that only 13% of participants completed >75% of prescribed treatment.

CONCLUSIONS:

In teenagers aged 13 to <17 years, improvement in amblyopic eye VA with the binocular iPad game used in this study was not found to be better than patching, and was possibly worse. Nevertheless, it remains unclear whether the minimal treatment response to binocular treatment was owing to poor treatment adherence or lack of treatment effect.

THE ROLE OF INTERACTIVE BINOCULAR TREATMENT SYSTEM IN AMBLYOPIA THERAPY.

Abstract

PURPOSE:

To determine the role of Interactive Binocular Treatment (I-BiT™) as a complementary method of patching in amblyopia therapy.

METHODS:

In this randomized clinical trial study, 50 unilateral amblyopic children (25 male/25 female) between 3 and 10 years with either best corrected visual acuity (BCVA) ≤20/30 in the amblyopic eye or a difference of BCVA ≥ 2 lines between the two eyes were included. They were randomly classified into the case and control groups (25 in each). Patching was recommended in both groups, and cases also received I-BiT™. Cases were asked to play I-BiT™ games through appropriate glasses with conjugate colored filters. Moving and fixed targets were shown to the amblyopic and non-amblyopic eyes, respectively. Playing games was continued 20 min in each session for 5 days a week within one month (total time: 6.6 h). Patching was continued for one month more in both groups to evaluate the continuous effect of I-BiT™. BCVA was measured at baseline, one month after beginning I-BiT™, and one month after cessation of I-BiT™.

RESULTS:

BCVA of amblyopic eyes in cases and controls were 0.34 ± 0.14 and 0.33 ± 0.17LogMAR at baseline which improved to 0.17 ± 0.14 and 0.26 ± 0.17 at one month, respectively. The difference was significant in each group (p < 0.001 for cases and p = 0.024 for controls) with more improvement in the case group (p < 0.001). One month after cessation of I-BiT™, BCVA difference between the two groups was not statistically significant. There was no case with recurrence of amblyopia.

CONCLUSION:

Based on our results, I-BiT™ seems to be effective in amblyopia therapy accompanied with patching. We recommend comparing I-BiT™ alone with patching in further studies. ClinicalTrials.gov Identifier: NCT02740725.

BINOCULAR THERAPY FOR CHILDHOOD AMBLYOPIA IMPROVES VISION WITHOUT BREAKING INTEROCULAR SUPPRESSION.

Abstract

Purpose:

Amblyopia is a common developmental visual impairment characterized by a substantial difference in acuity between the two eyes. Current monocular treatments, which promote use of the affected eye by occluding or blurring the fellow eye, improve acuity, but are hindered by poor compliance. Recently developed binocular treatments can produce rapid gains in visual function, thought to be as a result of reduced interocular suppression. We set out to develop an effective home-based binocular treatment system for amblyopia that would engage high levels of compliance but that would also allow us to assess the role of suppression in children’s response to binocular treatment.

Methods:

Balanced binocular viewing therapy (BBV) involves daily viewing of dichoptic movies (with «visibility» matched across the two eyes) and gameplay (to monitor compliance and suppression). Twenty-two children (3-11 years) with anisometropic (n = 7; group 1) and strabismic or combined mechanism amblyopia (group 2; n = 6 and 9, respectively) completed the study. Groups 1 and 2 were treated for a maximum of 8 or 24 weeks, respectively.

Results:

The treatment elicited high levels of compliance (on average, 89.4% ± 24.2% of daily dose in 68.23% ± 12.2% of days on treatment) and led to a mean improvement in acuity of 0.27 logMAR (SD 0.22) for the amblyopic eye. Importantly, acuity gains were not correlated with a reduction in suppression.

Conclusions:

BBV is a binocular treatment for amblyopia that can be self-administered at home (with remote monitoring), producing rapid and substantial benefits that cannot be solely mediated by a reduction in interocular suppression.

RESTORATION OF BINOCULAR VISION IN AMBLYOPIA.

Abstract

PURPOSE:

To develop a treatment for amblyopia based on re-establishing binocular vision.

METHODS:

A novel procedure is outlined for measuring and reducing the extent to which the fixing eye suppresses the fellow amblyopic eye in adults with amblyopia. We hypothesize that suppression renders a structurally binocular system, functionally monocular.

RESULTS:

We demonstrate that strabismic amblyopes can combine information normally between their eyes under viewing conditions where suppression is reduced by presenting stimuli of different contrast to each eye. Furthermore, we show that prolonged periods of binocular combination leads to a strengthening of binocular vision in strabismic amblyopes and eventual combination of binocular information under natural viewing conditions (stimuli of the same contrast in each eye). Concomitant improvement in monocular acuity of the amblyopic eye occurs with this reduction in suppression and strengthening of binocular fusion. Additionally, stereoscopic function was established in the majority of patients tested. We have implemented this approach on a headmounted device as well as on a handheld iPod.

CONCLUSION:

This provides the basis for a new treatment of amblyopia, one that is purely binocular and aimed at reducing suppression as a first step.

DICHOPTIC TRAINING ENABLES THE ADULT AMBLYOPTIC BRAIN TO LEARN.

Abstract

Adults with amblyopia, a common visual cortex disorder caused primarily by binocular disruption during an early critical period, do not respond to conventional therapy involving occlusion of one eye. But it is now clear that the adult human visual cortex has a significant degree of plasticity, suggesting that something must be actively preventing the adult brain from learning to see through the amblyopic eye. One possibility is an inhibitory signal from the contralateral eye that suppresses cortical inputs from the amblyopic eye. Such a gating mechanism could explain the apparent lack of plasticity within the adult amblyopic visual cortex. Here we provide direct evidence that alleviating suppression of the amblyopic eye through dichoptic stimulus presentation induces greater levels of plasticity than forced use of the amblyopic eye alone. This indicates that suppression is a key gating mechanism that prevents the amblyopic brain from learning to see.

FINE MOTOR SKILLS OF CHILDREN WITH AMBLYOPIA IMPROVE FOLLOWING BINOCULAR TREATMENT.

Abstract

PURPOSE:

The purpose of this study was to determine whether reduced fine motor skills in children with amblyopia improve after binocular treatment and whether improvements are sustained once treatment has ceased.

METHODS:

Fine motor skills (FMS [Bruininks-Oseretsky Test of Motor Proficiency]), visual acuity (VA [Early Treatment of Diabetic Retinopathy Study chart]) and level of binocular function (BF [Randot preschool stereoacuity and Worth 4 Dot]) were measured in children with amblyopia (n = 20; age: 8.5 ± 1.3 years; 11 anisometropic; 5 strabismic; 4 mixed) and in a group of visually normal children (n = 10; age: 9.63 ± 1.6 years). Eighteen children with amblyopia subsequently completed 5 weeks of binocular treatment provided by home-based dichoptic iPod game play. FMS, VA, and BF were retested at the end of treatment and 12 weeks after treatment cessation. All visually normal children also completed FMS measurements at baseline and 5 weeks later to assess test-retest variability of the FMS scores.

RESULTS:

Prior to treatment, FMS scores in children with amblyopia were poorer than those in children with normal vision (P < 0.05). In the children with amblyopia, binocular treatment significantly improved FMS scores (P < 0.05). Better baseline amblyopic eye VA and BF were associated with greater improvements in FMS score. Improvements were still evident at 12 weeks post treatment. In the visually normal children, FMS scores remained stable across the two test sessions.

CONCLUSIONS:

Binocular treatment provided by dichoptic iPod game play improved FMS performance in children with amblyopia, particularly in those with less severe amblyopia. Improvements were maintained at 3 months following cessation of treatment.

IMPROVED BINOCULAR OUTCOMES FOLLOWING BINOCULAR TREATMENT FOR CHILDHOOD AMBLYOPIA.

Abstract

Purpose:

Childhood amblyopia can be treated with binocular games or movies that rebalance contrast between the eyes, which is thought to reduce depth of interocular suppression so the child can experience binocular vision. While visual acuity gains have been reported following binocular treatment, studies rarely report gains in binocular outcomes (i.e., stereoacuity, suppression) in amblyopic children. Here, we evaluated binocular outcomes in children who had received binocular treatment for childhood amblyopia.

Methods:

Data for amblyopic children enrolled in two ongoing studies were pooled. The sample included 41 amblyopic children (6 strabismic, 21 anisometropic, 14 combined; age 4-10 years; ≤4 prism diopters [PD]) who received binocular treatment (20 game, 21 movies; prescribed 9-10 hours treatment). Amblyopic eye visual acuity and binocular outcomes (Randot Preschool Stereoacuity, extent of suppression, and depth of suppression) were assessed at baseline and at 2 weeks.

Results:

Mean amblyopic eye visual acuity (P < 0.001) and mean stereoacuity improved (P = 0.045), and mean extent (P = 0.005) and depth of suppression (P = 0.003) were reduced from baseline at the 2-week visit (87% game adherence, 100% movie adherence). Depth of suppression was reduced more in children aged <8 years than in those aged ≥8 years (P = 0.004). Worse baseline depth of suppression was correlated with a larger depth of suppression reduction at 2 weeks (P = 0.001).

Conclusions:

After 2 weeks, binocular treatment in amblyopic children improved visual acuity and binocular outcomes, reducing the extent and depth of suppression and improving stereoacuity. Binocular treatments that rebalance contrast to overcome suppression are a promising additional option for treating amblyopia.

BINOCULAR iPad TREATMENT FOR AMBLYOPIA IN PRESCHOOL CHILDREN.

Abstract

BACKGROUND:

Recent experimental evidence supports a role for binocular visual experience in the treatment of amblyopia. The purpose of this study was to determine whether repeated binocular visual experience with dichoptic iPad games could effectively treat amblyopia in preschool children.

METHODS:

A total of 50 consecutive amblyopic preschool children 3-6.9 years of age were assigned to play sham iPad games (first 5 children) or binocular iPad games (n = 45) for at least 4 hours per week for 4 weeks. Thirty (67%) children in the binocular iPad group and 4 (80%) in the sham iPad group were also treated with patching at a different time of day. Visual acuity and stereoacuity were assessed at baseline, at 4 weeks, and at 3 months after the cessation of game play.

RESULTS:

The sham iPad group had no significant improvement in visual acuity (t4 = 0.34, P = 0.75). In the binocular iPad group, mean visual acuity (plus or minus standard error) improved from 0.43 ± 0.03 at baseline to 0.34 ± 0.03 logMAR at 4 weeks (n = 45; paired t44 = 4.93; P < 0.0001). Stereoacuity did not significantly improve (t44 = 1.35, P = 0.18). Children who played the binocular iPad games for ≥8 hours (≥50% compliance) had significantly more visual acuity improvement than children who played 0-4 hours (t43 = 4.21, P = 0.0001).

CONCLUSIONS:

Repeated binocular experience, provided by dichoptic iPad game play, was more effective than sham iPad game play as a treatment for amblyopia in preschool children.

Copyright © 2015 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

A DICHOPTIC CUSTOM-MADE ACTION VIDEO GAME AS A TREATMENT FOR ADULT AMBLYOPIA.

Abstract

Previous studies have employed different experimental approaches to enhance visual function in adults with amblyopia including perceptual learning, videogame play, and dichoptic training. Here, we evaluated the efficacy of a novel dichoptic action videogame combining all three approaches. This experimental intervention was compared to a conventional, yet unstudied method of supervised occlusion while watching movies. Adults with unilateral amblyopia were assigned to either play the dichoptic action game (n=23; ‘game’ group), or to watch movies monocularly while the fellow eye was patched (n=15; ‘movies’ group) for a total of 40hours. Following training, visual acuity (VA) improved on average by ≈0.14logMAR (≈28%) in the game group, with improvements noted in both anisometropic and strabismic patients. This improvement is similar to that obtained following perceptual learning, video game play or dichoptic training. Surprisingly, patients with anisometropic amblyopia in the movies group showed similar improvement, revealing a greater impact of supervised occlusion in adults than typically thought. Stereoacuity, reading speed, and contrast sensitivity improved more for game group participants compared with movies group participants. Most improvements were largely retained following a 2-month no-contact period. This novel video game, which combines action gaming, perceptual learning and dichoptic presentation, results in VA improvements equivalent to those previously documented with each of these techniques alone. Our game intervention led to greater improvement than control training in a variety of visual functions, thus suggesting that this approach has promise for the treatment of adult amblyopia.

THE EFFECT OF BANGERTER FILTERS ON BINOCULAR FUNCTION IN OBSERVERS WITH AMBLYOPIA.

Abstract

PURPOSE:

We assessed whether partial occlusion of the nonamblyopic eye with Bangerter filters can immediately reduce suppression and promote binocular summation of contrast in observers with amblyopia.

METHODS:

In Experiment 1, suppression was measured for 22 observers (mean age, 20 years; range, 14-32 years; 10 females) with strabismic or anisometropic amblyopia and 10 controls using our previously established «balance point» protocol. Measurements were made at baseline and with 0.6-, 0.4-, and 0.2-strength Bangerter filters placed over the nonamblyopic/dominant eye. In Experiment 2, psychophysical measurements of contrast sensitivity were made under binocular and monocular viewing conditions for 25 observers with anisometropic amblyopia (mean age, 17 years; range, 11-28 years; 14 females) and 22 controls (mean age, 24 years; range, 22-27; 12 female). Measurements were made at baseline, and with 0.4- and 0.2-strength Bangerter filters placed over the nonamblyopic/dominant eye. Binocular summation ratios (BSRs) were calculated at baseline and with Bangerter filters in place.

RESULTS:

Experiment 1: Bangerter filters reduced suppression in observers with amblyopia and induced suppression in controls (P = 0.025). The 0.2-strength filter eliminated suppression in observers with amblyopia and this was not a visual acuity effect. Experiment 2: Bangerter filters were able to induce normal levels of binocular contrast summation in the group of observers with anisometropic amblyopia for a stimulus with a spatial frequency of 3 cycles per degree (cpd, P = 0.006). The filters reduced binocular summation in controls.

CONCLUSIONS:

Bangerter filters can immediately reduce suppression and promote binocular summation for mid/low spatial frequencies in observers with amblyopia.

 

[COMPUTERIZED OCULOMOTOR TRAINING IN DYSLEXIA: A RANDOMIZED, CROSSOVER CLINICAL TRIAL IN PEDIATRIC POPULATION].

Abstract

OBJECTIVE:

Several studies have reported abnormal oculomotor capacities leading to reading/writing difficulties among dyslexic children. However, no randomized clinical trial has been conducted to determine whether oculomotor training improves reading/writing skills of these children. The present study aims to evaluate the efficacy of computer-based oculomotor training among dyslexic children.

METHOD:

Crossover randomized trial with enrollment from January 12, 2015 to July 24, 2015, and follow-up to February 4, 2016. Eleven children (aged 7 to 12 years old) with dyslexia were included in a French psychiatric unit. The computer-based oculomotor training consisted of exercises focused on control of saccadic movements (reflexes and voluntary saccades), vergences and visual attention and memory. At baseline, 3 and 6 months, participants were assessed on reading and writing skills as well as phonological skills, visuo-attentional skills and verbal memory using the French batterie analytique du langage écrit (BALE). Saccadic and antisaccadic ocular movements (latencies and gains) were recorded using a specific device. Several Anova models were performed to test whether oculomotor training improves reading, writing and phonological, verbal memory and visuo-attentional skills. Our analyses were considered exploratory (alpha at 5%).

RESULTS:

No effect of oculomotor training was found on reading skills. However, oculomotor training was associated with a short-term effect (after 3 months of training) on several tests measuring phonological skills (syllabic suppression; P-value=0.022), visuo-attentional skills (search of anarchic verbal cues; P-value=0.035) and verbal memory (digit span backward; P-value=0.022) and with a long-term effect (3 months after the end of the 3 months of training) on a measure of writing skills (regular words; P-value=0.019). Finally, training was associated with an increase of saccadic latencies indicating an increase of visuo-attentional skills (P-value=0.026).

CONCLUSIONS:

Our results suggested that computer-based oculomotor training might be effective on writing skills and several cognitive skills among dyslexic children, but future clinical trials are needed to confirm our results.

RAPID IMPROVEMENT OF READING PERFORMANCE IN CHILDREN WITH DYSLEXIA BY ALTERING THE READING STRATEGY: A NOVEL APPROACH TO DIAGNOSES AND THERAPY OF READING DEFICIENCIES.

Abstract

BACKGROUND:

Reading disability is termed «dyslexia» if it is much lower than other cognitive abilities according to the intelligence quotient (IQ). This means that dyslexia is caused by an impairment of abilities other than those which the IQ requires. Therefore, reading performance should improve immediately if these impairments are either eliminated or compensated.

OBJECTIVE:

The experiments explore conditions under which these impairments are compensated and dyslexic children’s poor reading ability immediately improve.

METHODS:

Experiment 1 examined if reducing the number of letters in pseudowords, prolonging the time interval during which the gaze is directed to pseudowords, reducing the amplitude of saccades and prolonging the time interval that elapsed between the beginning of the presentation of a pseudoword and the beginning of the pronunciation of that word influences childrens’ reading performance. A group of 100 German children (71 boys and 29 girls) aged 8 to 13 years, who suffered from dyslexia according to the Zuerich Reading Test, were divided into a training group (n = 50) and an age-matched control group (n = 50) and tested. Both groups participated in experiment 1. Only the children in the training group participated in experiment 2, in which the children learned a compensatory reading strategy. The age – matched control group did not learn the compensatory reading strategy. In the training group, reading performance was tested before and after having learned the new reading strategy.

RESULTS:

Conditions were found under which all children were able to read 95% of the pseudowords correctly. After having learned a compensatory reading strategy, a mean 58.9% decrease in words read incorrectly was found after a single training session. The difference between the number of reading mistakes before and after the training session was highly significant (Wicoxon Test: p <  0.00001). The effect size showed that the compensatory reading strategy was highly effective (Hedges g = 1.7). The reading ability of an age-matched dyslexic control group showed no improvement.

CONCLUSIONS:

Dyslexic subjects’ reading performance improves significantly when they learn a new reading strategy.

EFFICACY OF VISION THERAPY IN CHILDREN WITH LEARNING DISABILITY AND ASSOCIATED BINOCULAR VISION ANOMALIES.

Abstract

Purpose

To report the frequency of binocular vision (BV) anomalies in children with specific learning disorders (SLD) and to assess the efficacy of vision therapy (VT) in children with a non-strabismic binocular vision anomaly (NSBVA).

Methods

The study was carried out at a centre for learning disability (LD). Comprehensive eye examination and binocular vision assessment was carried out for 94 children (mean (SD) age: 15 (2.2) years) diagnosed with specific learning disorder. BV assessment was done for children with best corrected visual acuity of ≥6/9 – N6, cooperative for examination and free from any ocular pathology. For children with a diagnosis of NSBVA (n = 46), 24 children were randomized to VT and no intervention was provided to the other 22 children who served as experimental controls. At the end of 10 sessions of vision therapy, BV assessment was performed for both the intervention and non-intervention groups.

Results

Binocular vision anomalies were found in 59 children (62.8%) among which 22% (n = 13) had strabismic binocular vision anomalies (SBVA) and 78% (n = 46) had a NSBVA. Accommodative infacility (AIF) was the commonest of the NSBVA and found in 67%, followed by convergence insufficiency (CI) in 25%. Post-vision therapy, the intervention group showed significant improvement in all the BV parameters (Wilcoxon signed rank test, p < 0.05) except negative fusional vergence.

Conclusion

Children with specific learning disorders have a high frequency of binocular vision disorders and vision therapy plays a significant role in improving the BV parameters. Children with SLD should be screened for BV anomalies as it could potentially be an added hindrance to the reading difficulty in this special population.

ACTION VIDEO GAMES IMPROVE READING ABILITIES AND VISUAL-TO-AUDITORY ATTENTIONAL SHIFTING IN ENGLISH-SPEAKING CHILDREN WITH DYSLEXIA. 

Abstract

Dyslexia is characterized by difficulties in learning to read and there is some evidence that action video games (AVG), without any direct phonological or orthographic stimulation, improve reading efficiency in Italian children with dyslexia. However, the cognitive mechanism underlying this improvement and the extent to which the benefits of AVG training would generalize to deep English orthography, remain two critical questions. During reading acquisition, children have to integrate written letters with speech sounds, rapidly shifting their attention from visual to auditory modality. In our study, we tested reading skills and phonological working memory, visuo-spatial attention, auditory, visual and audio-visual stimuli localization, and cross-sensory attentional shifting in two matched groups of English-speaking children with dyslexia before and after they played AVG or non-action video games. The speed of words recognition and phonological decoding increased after playing AVG, but not non-action video games. Furthermore, focused visuo-spatial attention and visual-to-auditory attentional shifting also improved only after AVG training. This unconventional reading remediation program also increased phonological short-term memory and phoneme blending skills. Our report shows that an enhancement of visuo-spatial attention and phonological working memory, and an acceleration of visual-to-auditory attentional shifting can directly translate into better reading in English-speaking children with dyslexia.

IMPROVING ACTION VIDEO GAMES ABILITIES INCREASES THE PHONOLOGICAL DECODING SPEED AND PHONOLOGICAL SHORT-TERM MEMORY IN CHILDREN WITH DEVELOPMENTAL DYSLEXIA.

Abstract

Learning to read is extremely difficult for about 10% of the children because they are affected by a heritable neurobiological disorder called developmental dyslexia (DD). The causal role of cognitive deficits typically associated to DD can be investigated through intervention studies. It has been demonstrated that visual-attention and reading speed could be simultaneously improved by using action video game (AVG) training both in shallow and deep alphabetic orthographies. Here, in a clinical study we showed that after this general-domain behavioral intervention both the phonological decoding speed and phonological short-term memory were increased only in DD children in which their video game score was improved. These findings confirm that an AVG training enhances the efficiency of both visual and auditory processing. The plasticity of the multi-sensory attentional network could explain the reading and reading-related improvements induced by the AVG training in children with DD.

ACTION VIDEO GAMES MAKE DYSLEXIC CHILDREN READ BETTER.

Abstract

Learning to read is extremely difficult for about 10% of children; they are affected by a neurodevelopmental disorder called dyslexia [1, 2]. The neurocognitive causes of dyslexia are still hotly debated [3-12]. Dyslexia remediation is far from being fully achieved [13], and the current treatments demand high levels of resources [1]. Here, we demonstrate that only 12 hr of playing action video games-not involving any direct phonological or orthographic training-drastically improve the reading abilities of children with dyslexia. We tested reading, phonological, and attentional skills in two matched groups of children with dyslexia before and after they played action or nonaction video games for nine sessions of 80 min per day. We found that only playing action video games improved children’s reading speed, without any cost in accuracy, more so than 1 year of spontaneous reading development and more than or equal to highly demanding traditional reading treatments. Attentional skills also improved during action video game training. It has been demonstrated that action video games efficiently improve attention abilities [14, 15]; our results showed that this attention improvement can directly translate into better reading abilities, providing a new, fast, fun remediation of dyslexia that has theoretical relevance in unveiling the causal role of attention in reading acquisition.

ASSESMENT OF NEURO-OPTOMETRIC REHABILITATION USING THE DEVELOPMENTAL EYE MOVEMENT (DEM) TEST IN ADULTS WITH ACQUIRED BRAIN INJURY.

Abstract

PURPOSE:

This pilot study sought to determine the efficacy of using the Developmental Eye Movement (DEM) test in the adult, acquired brain injury (ABI) population to quantify clinically the effects of controlled, laboratory-performed, oculomotor-based vision therapy/vision rehabilitation.

METHODS:

Nine adult subjects with mild traumatic brain injury (mTBI) and five with stroke were assessed before and after an eight-week, computer-based, versional oculomotor (fixation, saccades, pursuit, and simulated reading) training program (9.6h total). The protocol incorporated a cross-over, interventional design with and without the addition of auditory feedback regarding two-dimensional eye position. The clinical outcome measure was the Developmental Eye Movement (DEM) test score (ratio, errors) taken before, midway, and immediately following training.

RESULTS:

For the DEM ratio parameter, improvements were found in 80-89% of the subjects. For the DEM error parameter, improvements were found in 100% of the subjects. Incorporation of the auditory feedback component revealed a trend toward enhanced performance. The findings were similar for both DEM parameters, as well as for incorporation of the auditory feedback, in both diagnostic groups.

DISCUSSION:

The results of the present study demonstrated considerable improvements in the DEM test scores following the oculomotor-based training, thus reflecting more time-optimal and accurate saccadic tracking after the training. The DEM test should be considered as another clinical test of global saccadic tracking performance in the ABI population.

EFFECT OF OCULOMOTOR VISION REHABILITATION ON THE VISUAL-EVOKED POTENTIAL AND VISUAL ATTENTION IN MILD TRAUMATIC  BRAIN INJURY.

Abstract

PRIMARY OBJECTIVE:

The purpose of the experiment was to investigate the effect of oculomotor vision rehabilitation (OVR) on the visual-evoked potential (VEP) and visual attention in the mTBI population.

RESEARCH DESIGN AND METHODS:

Subjects (n = 7) were adults with a history of mild traumatic brain injury (mTBI). Each received 9 hours of OVR over a 6-week period. The effects of OVR on VEP amplitude and latency, the attention-related alpha band (8-13 Hz) power (µV(2)) and the clinical Visual Search and Attention Test (VSAT) were assessed before and after the OVR.

RESULTS:

After the OVR, the VEP amplitude increased and its variability decreased. There was no change in VEP latency, which was normal. Alpha band power increased, as did the VSAT score, following the OVR.

CONCLUSIONS:

The significant changes in most test parameters suggest that OVR affects the visual system at early visuo-cortical levels, as well as other pathways which are involved in visual attention.

VISION THERAPY FOR BINOCULAR DYSFUNCTION POST BRAIN INJURY.

Abstract

PURPOSE:

To prospectively evaluate the effectiveness of home-based computer vergence therapy for the treatment of binocular vision disorders in adults at least 3 months after an acquired brain injury.

METHODS:

Eligibility criteria included presence of binocular dysfunction characterized by receded near point of convergence (≥6 cm break), insufficient positive fusional vergence at near (failing Sheard’s criterion or <15△ blur or break), insufficient negative fusional vergence at near (<12△ blur or break), and/or reduced vergence facility at near (<15 cycles per minute with 12△BO/3△BI). Participants were prescribed 12 weeks of home-based computer vergence therapy. Phoria (cover test), negative fusional vergence, positive fusional vergence, near point of convergence, vergence facility, and symptoms (convergence insufficiency symptom survey [CISS]) were assessed at baseline and after 4, 8, and 12 weeks of prescribed therapy. ANOVA was used to evaluate change in each measure. Percentage successful was also determined.

RESULTS:

Nineteen participants were enrolled (mean age 45.4 ± 12.9 years); six participants were lost to follow-up. Baseline findings were orthophoria at distance, 7.2△ exophoria at near, near point of convergence break = 17.5 cm, near point of convergence recovery = 21.8 cm, negative fusional vergence = 12.3△, positive fusional vergence blur = 8.4△, vergence facility = 3.9 cycles per minute, and CISS = 32.1. ANOVA showed a statistically significant improvement for near point of convergence break (p = 0.002) and recovery (p < 0.001), positive fusional vergence blur (p < 0.0001), break (p < 0.0001), and recovery (p < 0.0001), negative fusional vergence blur (p = 0.037), break (p = 0.003), and recovery (p = 0.006), vergence facility (p < 0.0001), and CISS (p = 0.0001). The percentage of patients who were classified as «successful» or «improved» was 69% for near point of convergence (<6 cm or decrease of ≥4 cm), 77% for positive fusional vergence (>15△ and passing Sheard’s criterion or increase of ≥10△), 77% for negative fusional vergence (≥12△ or increase of ≥6△), 62% for positive fusional vergence and near point of convergence composite, and 92% for vergence facility (15 cycles per minute or increase of 3 cycles per minute).

CONCLUSIONS:

The majority of participants who completed the study experienced meaningful improvements in signs and symptoms.

EFFECT OF OCULOMOTOR REHABILITATION ON ACCOMMODATIVE RESPONSIVITY IN MILD TRAUMATIC BRAIN INJURY.

Abstract

Accommodative dysfunction is a common oculomotor sequelae of mild traumatic brain injury (mTBI). This study evaluated a range of dynamic (objective) and static (subjective) measures of accommodation in 12 nonstrabismic individuals with mTBI and near vision-related symptoms before and after oculomotor training (OMT) and placebo (P) training (6 wk, two sessions per week, 3 h of training each). Following OMT, the dynamics of accommodation improved markedly. Clinically, there was a significant increase in the maximum accommodative amplitude both monocularly and binocularly. In addition, the near vision symptoms reduced along with improved visual attention. None of the measures were found to change significantly following P training. These results provide evidence for a significant positive effect of the accommodatively based OMT on accommodative responsivity. Such improvement is suggestive of oculomotor learning, demonstrating considerable residual brain-visual system plasticity in the adult compromised brain.

VISUAL FIELD OF RECOVERY AFTER VISION RESTORATION THERAPY (VRT) IS INDEPENDENT OF EYE MOVEMENTS: AN EYE TRACKER STUDY.

Abstract

AIM:

It has been argued that patients with visual field defects compensate for their deficit by making more frequent eye movements toward the hemianopic field and that visual field enlargements found after vision restoration therapy (VRT) may be an artefact of such eye movements. In order to determine if this was correct, we recorded eye movements in hemianopic subjects before and after VRT.

METHODS:

Visual fields were measured in subjects with homonymous visual field defects (n=15) caused by trauma, cerebral ischemia or haemorrhage (lesion age >6 months). Visual field charts were plotted using both high-resolution perimetry (HRP) and conventional perimetry before and after a 3-month period of VRT, with eye movements being recorded with a 2D-eye tracker. This permitted quantification of eye positions and measurements of deviation from fixation.

RESULTS:

VRT lead to significant visual field enlargements as indicated by an increase of stimulus detection of 3.8% when tested using HRP and about 2.2% (OD) and 3.5% (OS) fewer misses with conventional perimetry. Eye movements were expressed as the standard deviations (S.D.) of the eye position recordings from fixation. Before VRT, the S.D. was +/-0.82 degrees horizontally and +/-1.16 degrees vertically; after VRT, it was +/-0.68 degrees and +/-1.39 degrees , respectively. A cluster analysis of the horizontal eye movements before VRT showed three types of subjects with (i) small (n=7), (ii) medium (n=7) or (iii) large fixation instability (n=1). Saccades were directed equally to the right or the left side; i.e., with no preference toward the blind hemifield. After VRT, many subjects showed a smaller variability of horizontal eye movements. Before VRT, 81.6% of the recorded eye positions were found within a range of 1 degrees horizontally from fixation, whereas after VRT, 88.3% were within that range. In the 2 degrees range, we found 94.8% before and 98.9% after VRT. Subjects moved their eyes 5 degrees or more 0.3% of the time before VRT versus 0.1% after VRT. Thus, in this study, subjects with homonymous visual field defects who were attempting to fixate a central target while their fields were being plotted, typically showed brief horizontal shifts with no preference toward or away from the blind hemifield. These eye movements were usually less than 1 degrees from fixation. Large saccades toward the blind field after VRT were very rare.

CONCLUSION:

VRT has no effect on either the direction or the amplitude of horizontal eye movements during visual field testing. These results argue against the theory that the visual field enlargements are artefacts induced by eye movements.

OBJECTIVE ASSESSMENT OF VERGENCE AFTER TREATMENT OF CONCUSSION-RELATED CI: A PILOT STUDY.

Abstract

PURPOSE:

To evaluate changes in objective measures of disparity vergence after office-based vision therapy (OBVT) for concussion-related convergence insufficiency (CI) and determine the feasibility of using this objective assessment as an outcome measure in a clinical trial.

METHODS:

This was a prospective, observational trial. All participants were treated with weekly OBVT with home reinforcement. Participants included two adolescents and three young adults with concussion-related, symptomatic CI. The primary outcome measure was average peak velocity for 4° symmetrical convergence steps. Other objective outcome measures of disparity vergence included time to peak velocity, latency, accuracy, settling time, and main sequence. We also evaluated saccadic eye movements using the same outcome measures. Changes in clinical measures (near point of convergence, positive fusional vergence at near, Convergence Insufficiency Symptom Survey [CISS] score) were evaluated.

RESULTS:

There were statistically significant and clinically meaningful changes in all clinical measures for convergence. Four of the five subjects met clinical success criteria. For the objective measures, we found a statistically significant increase in peak velocity, response accuracy to 4° symmetrical convergence and divergence step stimuli, and the main sequence ratio for convergence step stimuli. Objective saccadic eye movements (5 and 10°) appeared normal pre-OBVT and did not show any significant change after treatment.

CONCLUSIONS:

This is the first report of the use of objective measures of disparity vergence as outcome measures for concussion-related convergence insufficiency. These measures provide additional information that is not accessible with clinical tests about underlying physiological mechanisms leading to changes in clinical findings and symptoms. The study results also demonstrate that patients with concussion can tolerate the visual demands (over 200 vergence and versional eye movements) during the 25-minute testing time and suggest that these measures could be used in a large-scale randomized clinical trial of concussion-related CI as outcome measures.

ALTERED CONNECTIVITY OF THE DORSAL AND VENTRAL VISUAL REGIONS IN DYSLEXIC CHILDREN: A RESTING-STATE fMRI STUDY.

Abstract

While there is emerging evidence from behavioral studies that visual attention skills are impaired in dyslexia, the corresponding neural mechanism (i.e., deficits in the dorsal visual region) needs further investigation. We used resting-state fMRI to explore the functional connectivity (FC) patterns of the left intraparietal sulcus (IPS) and the visual word form area (VWFA) in dyslexic children (N = 21, age mean = 12) and age-matched controls (N = 26, age mean = 12). The results showed that the left IPS and the VWFA were functionally connected to each other in both groups and that both were functionally connected to left middle frontal gyrus (MFG). Importantly, we observed significant group differences in FC between the left IPS and the left MFG and between the VWFA and the left MFG. In addition, the strengths of the identified FCs were significantly correlated with the score of fluent reading, which required obvious eye movement and visual attention processing, but not with the lexical decision score. We conclude that dyslexics have deficits in the network composed of the prefrontal, dorsal visual and ventral visual regions and may have a lack of modulation from the left MFG to the dorsal and ventral visual regions.

FREQUENCY OF VISUAL DEFICITS IN CHILDREN WITH DEVELOPMENTAL DYSLEXIA.

Abstract

Importance:

Developmental dyslexia (DD) is a specific learning disability of neurobiological origin whose core cognitive deficit is widely believed to involve language (phonological) processing. Although reading is also a visual task, the potential role of vision in DD has been controversial, and little is known about the integrity of visual function in individuals with DD.

Objective:

To assess the frequency of visual deficits (specifically vergence, accommodation, and ocular motor tracking) in children with DD compared with a control group of typically developing readers.

Design, Setting, and Participants:

A prospective, uncontrolled observational study was conducted from May 28 to October 17, 2016, in an outpatient ophthalmology ambulatory clinic among 29 children with DD and 33 typically developing (TD) children.

Main Outcomes and Measures:

Primary outcomes were frequencies of deficits in vergence (amplitude, fusional ranges, and facility), accommodation (amplitude, facility, and accuracy), and ocular motor tracking (Developmental Eye Movement test and Visagraph eye tracker).

Results:

Among the children with DD (10 girls and 19 boys; mean [SD] age, 10.3 [1.2] years) and the TD group (21 girls and 12 boys; mean [SD] age, 9.4 [1.4] years), accommodation deficits were more frequent in the DD group than the TD group (16 [55%] vs 3 [9%]; difference = 46%; 95% CI, 25%-67%; P < .001). For ocular motor tracking, 18 children in the DD group (62%) had scores in the impaired range (in the Developmental Eye Movement test, Visagraph, or both) vs 5 children in the TD group (15%) (difference, 47%; 95% CI, 25%-69%; P < .001). Vergence deficits occurred in 10 children in the DD group (34%) and 5 children in the TD group (15%) (difference, 19%; 95% CI, -2.2% to 41%; P = .08). In all, 23 children in the DD group (79%) and 11 children in the TD group (33%) had deficits in 1 or more domain of visual function (difference, 46%; 95% CI, 23%-69%; P < .001).

Conclusions and Relevance:

These findings suggest that deficits in visual function are far more prevalent in school-aged children with DD than in TD readers, but the possible cause and clinical relevance of these deficits are uncertain. Further study is needed to determine the extent to which treating these deficits can improve visual symptoms and/or reading parameters.

DEVELOPMENTAL DYSLEXIA AND VISION

Abstract

Developmental dyslexia affects almost 10% of school-aged children and represents a significant public health problem. Its etiology is unknown. The consistent presence of phonological difficulties combined with an inability to manipulate language sounds and the grapheme–phoneme conversion is widely acknowledged. Numerous scientific studies have also documented the presence of eye movement anomalies and deficits of perception of low contrast, low spatial frequency, and high frequency temporal visual information in dyslexics. Anomalies of visual attention with short visual attention spans have also been demonstrated in a large number of cases. Spatial orientation is also affected in dyslexics who manifest a preference for spatial attention to the right. This asymmetry may be so pronounced that it leads to a veritable neglect of space on the left side. The evaluation of treatments proposed to dyslexics whether speech or oriented towards the visual anomalies remains fragmentary. The advent of new explanatory theories, notably cerebellar, magnocellular, or proprioceptive, is an incentive for ophthalmologists to enter the world of multimodal cognition given the importance of the eye’s visual input.

SELF-REPORTED VISUAL SYMPTOMS IN CHILDREN WITH  DEVELOPMENTAL DYSLEXIA.

Abstract

Although there are many anecdotal reports of children with developmental dyslexia complaining of vision symptoms when reading, empirical studies are lacking. The primary aim of the present study was to document self-reported vision-related symptoms in children with developmental dyslexia and typically reading peers. We also explored whether vision symptoms were correlated with sensorimotor measures of vergence, accommodation and ocular motor tracking skills. Using a prospective group comparison observational design, we assessed 28 children with developmental dyslexia (DD) and 33 typically reading children (TR) 7-11 years of age. Participants completed psychoeducational testing, a comprehensive sensorimotor eye examination, and the Convergence Insufficiency Symptom Survey (CISS), which includes 9 items pertaining to vision-related symptoms (CISS-V) and 6 that could have cognitive influence (CISS-C). CISS-V were significantly greater in DD than TR children. Ocular motor tracking, assessed by an infra-red limbal eye tracker while reading text, was most clearly associated with the visual symptoms, but only within the DD group. Vision-related symptom surveys followed by a comprehensive eye examination with detailed evaluation of sensorimotor functioning for those who report a high prevalence of symptoms may be clinically relevant for children with DD.

HOW THE ASPECTS CAN BE CRUCIAL IN READING ACQUISITION? THE INTRIGUING CASE OF CROWDING AND DEVELOPMENTAL DYSLEXIA.

Abstract

Developmental dyslexia (DD) is the most common neurodevelopmental disorder (about 10% of children across cultures) characterized by severe difficulties in learning to read. According to the dominant view, DD is considered a phonological processing impairment that might be linked to a cross-modal, letter-to-speech sound integration deficit. However, new theories-supported by consistent data-suggest that mild deficits in low-level visual and auditory processing can lead to DD. This evidence supports the probabilistic and multifactorial approach for DD. Among others, an interesting visual deficit that is often associated with DD is excessive visual crowding. Crowding is defined as difficulty in the ability to recognize objects when surrounded by similar items. Crowding, typically observed in peripheral vision, could be modulated by attentional processes. The direct consequence of stronger crowding on reading is the inability to recognize letters when they are surrounded by other letters. This problem directly translates to reading at a slower speed and being more prone to making errors while reading. Our aim is to review the literature supporting the important role of crowding in DD. Moreover, we are interested in proposing new possible studies in order to clarify whether the observed excessive crowding could be a cause rather than an effect of DD. Finally, we also suggest possible remediation and even prevention programs that could be based on reducing the crowding in children with or at risk for DD without involving any phonological or orthographic training.

PERCEPTUAL LEARNING AS A POSSIBLE NEW APPROACH FOR REMEDIATION AND PREVENTION OF DEVELOPMENTAL DYSLEXIA.

Abstract

Learning to read is extremely difficult for about 10% of children across cultures because they are affected by developmental dyslexia (DD). According to the dominant view, DD is considered an auditory-phonological processing deficit. However, accumulating evidence from developmental and clinical vision science, suggests that the basic cross-modal letter-to-speech sound integration deficit in DD might arise from a mild atypical development of the magnocellular-dorsal pathway which also contains the main fronto-parietal attentional network. Letters have to be precisely selected from irrelevant and cluttering letters by rapid orienting of visual attention before the correct letter-to-speech sound integration applies. Our aim is to review the literature supporting a possible role of perceptual learning (PL) in helping to solve the puzzle called DD. PL is defined as improvement of perceptual skills with practice. Based on the previous literature showing how PL is able to selectively change visual abilities, we here propose to use PL to improve the impaired visual functions characterizing DD and, in particular, the visual deficits that could be developmentally related to an early magnocellular-dorsal pathway and selective attention dysfunction. The crucial visual attention deficits that are causally linked to DD could be, indeed, strongly reduced by training the magnocellular-dorsal pathway with the PL, and learning to read for children with DD would not be anymore such a difficult task. This new remediation approach – not involving any phonological or orthographic training – could be also used to develop new prevention programs for pre-reading children at DD risk.

THE MAGNOCELLULAR  THEORY OF DEVELOPMENTAL DYSLEXIA.

Abstract

Low literacy is termed ‘developmental dyslexia’ when reading is significantly behind that expected from the intelligence quotient (IQ) in the presence of other symptoms–incoordination, left-right confusions, poor sequencing–that characterize it as a neurological syndrome. 5-10% of children, particularly boys, are found to be dyslexic. Reading requires the acquisition of good orthographic skills for recognising the visual form of words which allows one to access their meaning directly. It also requires the development of good phonological skills for sounding out unfamiliar words using knowledge of letter sound conversion rules. In the dyslexic brain, temporoparietal language areas on the two sides are symmetrical without the normal left-sided advantage. Also brain ‘warts’ (ectopias) are found, particularly clustered round the left temporoparietal language areas. The visual magnocellular system is responsible for timing visual events when reading. It therefore signals any visual motion that occurs if unintended movements lead to images moving off the fovea (‘retinal slip’). These signals are then used to bring the eyes back on target. Thus, sensitivity to visual motion seems to help determine how well orthographic skill can develop in both good and bad readers. In dyslexics, the development of the visual magnocellular system is impaired: development of the magnocellular layers of the dyslexic lateral geniculate nucleus (LGN) is abnormal; their motion sensitivity is reduced; many dyslexics show unsteady binocular fixation; hence poor visual localization, particularly on the left side (left neglect). Dyslexics’ binocular instability and visual perceptual instability, therefore, can cause the letters they are trying to read to appear to move around and cross over each other. Hence, blanking one eye (monocular occlusion) can improve reading. Thus, good magnocellular function is essential for high motion sensitivity and stable binocular fixation, hence proper development of orthographic skills. Many dyslexics also have auditory/phonological problems. Distinguishing letter sounds depends on picking up the changes in sound frequency and amplitude that characterize them. Thus, high frequency (FM) and amplitude modulation (AM) sensitivity helps the development of good phonological skill, and low sensitivity impedes the acquisition of these skills. Thus dyslexics’ sensitivity to FM and AM is significantly lower than that of good readers and this explains their problems with phonology. The cerebellum is the head ganglion of magnocellular systems; it contributes to binocular fixation and to inner speech for sounding out words, and it is clearly defective in dyslexics. Thus, there is evidence that most reading problems have a fundamental sensorimotor cause. But why do magnocellular systems fail to develop properly? There is a clear genetic basis for impaired development of magnocells throughout the brain. The best understood linkage is to the region of the Major Histocompatibility Complex (MHC) Class 1 on the short arm of chromosome 6 which helps to control the production of antibodies. The development of magnocells may be impaired by autoantibodies affecting the developing brain. Magnocells also need high amounts of polyunsaturated fatty acids to preserve the membrane flexibility that permits the rapid conformational changes of channel proteins which underlie their transient sensitivity. But the genes that underlie magnocellular weakness would not be so common unless there were compensating advantages to dyslexia. In developmental dyslexics there may be heightened development of parvocellular systems that underlie their holistic, artistic, ‘seeing the whole picture’ and entrepreneurial talents.

VISUAL SEARCH PERFORMANCE IN DYSLEXIA.

Abstract

According to the magnocellular theory of dyslexia, otherwise intelligent children may fail to learn to read because of abnormalities in the magnocellular layers of the lateral geniculate nucleus (mLGN). If this were the case, one would predict that dyslexic subjects who show a deficit on low-level psychophysical tasks which tax the magnocellular system would also have deficits on higher-level visual tasks which do not rely on the properties of mLGN cells but depend upon the functioning of areas whose main inputs originate in the mLGN. In other words, magnocellular deficits should be traceable at later stages of visual processing. One area where such later processing is thought to occur is the posterior parietal cortex, damage to which impairs function on some classes of visual search. To test this hypothesis, we tested two groups of dyslexic subjects and a group of non-dyslexic controls on a range of visual search tasks. One group of dyslexic subjects had elevated motion coherence thresholds, a sign of deficits at the early levels (e.g. mLGN) of visual processing, and the other group had normal motion coherence thresholds. If the magnocellular deficits extended to the parietal cortex, it follows that the subjects with elevated motion coherence thresholds should have deficit in visual search, whereas those with normal motion coherence thresholds should not. The dyslexics with a motion coherence deficit were also impaired on serial visual search tasks but not on a parallel search. The dyslexics with normal motion coherence performance were unimpaired on visual search. The deficit was expressed as an elevation in reaction times, but there was no difference between the groups either in error rates or in the way the tasks were ranked according to difficulty. The results suggest that those dyslexics who have visual problems related to magnocellular functions also have visual-attentional problems related to the functions of areas such as the parietal cortex, which are dominated by inputs originating in the magnocellular LGN.

A CASUAL LINK BETWEEN VISUAL SPATIAL ATTENTION AND READING ACQUISITION.

Abstract

Reading is a unique, cognitive human skill crucial to life in modern societies, but, for about 10% of the children, learning to read is extremely difficult. They are affected by a neurodevelopmental disorder called dyslexia. Although impaired auditory and speech sound processing is widely assumed to characterize dyslexic individuals, emerging evidence suggests that dyslexia could arise from a more basic cross-modal letter-to-speech sound integration deficit. Letters have to be precisely selected from irrelevant and cluttering letters by rapid orienting of visual attention before the correct letter-to-speech sound integration applies. Here we ask whether prereading visual parietal-attention functioning may explain future reading emergence and development. The present 3 year longitudinal study shows that prereading attentional orienting–assessed by serial search performance and spatial cueing facilitation–captures future reading acquisition skills in grades 1 and 2 after controlling for age, nonverbal IQ, speech-sound processing, and nonalphabetic cross-modal mapping. Our findings provide the first evidence that visual spatial attention in preschoolers specifically predicts future reading acquisition, suggesting new approaches for early identification and efficient prevention of dyslexia.

VISUAL SPATIAL ATTENTION AND SPEECH SEGMENTATION ARE BOTH IMPAIRED IN PRESCHOOLERS AT FAMILIAL RISK FOR DEVELOPMENTAL DYSLEXIA.

Abstract

Phonological skills are foundational of reading acquisition and impaired phonological processing is widely assumed to characterize dyslexic individuals. However, reading by phonological decoding also requires rapid selection of sublexical orthographic units through serial attentional orienting, and recent studies have shown that visual spatial attention is impaired in dyslexic children. Our study investigated these different neurocognitive dysfunctions, before reading acquisition, in a sample of preschoolers including children with (N=20) and without (N=67) familial risk for developmental dyslexia. Children were tested on phonological skills, rapid automatized naming, and visual spatial attention. At-risk children presented deficits in both visual spatial attention and syllabic segmentation at the group level. Moreover, the combination of visual spatial attention and syllabic segmentation scores was more reliable than either single measure for the identification of at-risk children. These findings suggest that both visuo-attentional and perisylvian-auditory dysfunctions might adversely affect reading acquisition, and may offer a new approach for early identification and remediation of developmental dyslexia.

THE ROLE OF VISUAL-SPATIAL ABILITIES IN DYSLEXIA: AGE DIFFERENCES IN CHILDREN’S READING?

Abstract

Reading is a highly complex process in which integrative neurocognitive functions are required. Visual-spatial abilities play a pivotal role because of the multi-faceted visual sensory processing involved in reading. Several studies show that children with developmental dyslexia (DD) fail to develop effective visual strategies and that some reading difficulties are linked to visual-spatial deficits. However, the relationship between visual-spatial skills and reading abilities is still a controversial issue. Crucially, the role that age plays has not been investigated in depth in this population, and it is still not clear if visual-spatial abilities differ across educational stages in DD. The aim of the present study was to investigate visual-spatial abilities in children with DD and in age-matched normal readers (NR) according to different educational stages: in children attending primary school and in children and adolescents attending secondary school. Moreover, in order to verify whether visual-spatial measures could predict reading performance, a regression analysis has been performed in younger and older children. The results showed that younger children with DD performed significantly worse than NR in a mental rotation task, a more-local visual-spatial task, a more-global visual-perceptual task and a visual-motor integration task. However, older children with DD showed deficits in the more-global visual-perceptual task, in a mental rotation task and in a visual attention task. In younger children, the regression analysis documented that reading abilities are predicted by the visual-motor integration task, while in older children only the more-global visual-perceptual task predicted reading performances. Present findings showed that visual-spatial deficits in children with DD were age-dependent and that visual-spatial abilities engaged in reading varied across different educational stages. In order to better understand their potential role in affecting reading, a comprehensive description and a multi-componential evaluation of visual-spatial abilities is needed with children with DD.

EXPLORING THE LINK BETWEEN VISUAL PERCEPTION, VISUAL-MOTOR INTEGRATION, AND READING IN NORMAL DEVELOPING AND IMPAIRED CHILDREN USING DTVP-2.

Abstract

Reading is known to be primarily a linguistic task. However, to successfully decode written words, children also need to develop good visual-perception skills. Furthermore, motor skills are implicated in letter recognition and reading acquisition. Three studies have been designed to determine the link between reading, visual perception, and visual-motor integration using the Developmental Test of Visual Perception version 2 (DTVP-2). Study 1 tests how visual perception and visual-motor integration in kindergarten predict reading outcomes in Grade 1, in typical developing children. Study 2 is aimed at finding out if these skills can be seen as clinical markers in dyslexic children (DD). Study 3 determines if visual-motor integration and motor-reduced visual perception can distinguish DD children according to whether they exhibit or not developmental coordination disorder (DCD). Results showed that phonological awareness and visual-motor integration predicted reading outcomes one year later. DTVP-2 demonstrated similarities and differences in visual-motor integration and motor-reduced visual perception between children with DD, DCD, and both of these deficits. DTVP-2 is a suitable tool to investigate links between visual perception, visual-motor integration and reading, and to differentiate cognitive profiles of children with developmental disabilities (i.e. DD, DCD, and comorbid children).

 

VISUAL IMPAIRMENT AND TRAITS OF AUTISM IN CHILDREN.

Abstract

Visual impairment present from birth or from an early childhood may lead to psychosocial and emotional disorders. 11-40% of children in the group with visual impairment show traits of autism. The aim of this paper was to present the selected examples of how visual impairment in children is related to the occurrence of autism and to describe the available tools for diagnosing autism in children with visual impairment. So far the relation between visual impairment in children and autism has not been sufficiently confirmed. Psychiatric and psychological diagnosis of children with visual impairment has some difficulties in differentiating between «blindism» and traits typical for autism resulting from a lack of standardized diagnostic tools used to diagnosing children with visual impairment. Another difficulty in diagnosing autism in children with visual impairment is the coexistence of other disabilities in case of most children with vision impairment. Additionally, apart from difficulties in diagnosing autistic disorders in children with eye dysfunctions there is also a question of what tools should be used in therapy and rehabilitation of patients.

VISION IN AUTISM SPECTRUM DISORDERS.

Abstract

Autism spectrum disorders (ASDs) are developmental disorders which are thought primarily to affect social functioning. However, there is now a growing body of evidence that unusual sensory processing is at least a concomitant and possibly the cause of many of the behavioural signs and symptoms of ASD. A comprehensive and critical review of the phenomenological, empirical, neuroscientific and theoretical literature pertaining to visual processing in ASD is presented, along with a brief justification of a new theory which may help to explain some of the data, and link it with other current hypotheses about the genetic and neural aetiologies of this enigmatic condition.

CONTRAST SENSITIVITY FOR MOTION DETECTION AND DIRECTION DISCRIMINATION IN ADOLESCENTS WITH AUTISM SPECTRUM DISORDERS AND THEIR SIBLINGS.

Abstract

The magnocellular (M) pathway hypothesis proposes that impaired visual motion perception observed in individuals with Autism Spectrum Disorders (ASD) might be mediated by atypical functioning of the subcortical M pathway, as this pathway provides the bulk of visual input to cortical motion detectors. To test this hypothesis, we measured luminance and chromatic contrast sensitivity, thought to tap M and Parvocellular (P) pathway processing, respectively. We also tested the hypothesis that motion processing is impaired in ASD using a novel paradigm that measures motion processing while controlling for detectabilty. Specifically, this paradigm compares contrast sensitivity for detection of a moving grating with contrast sensitivity for direction-of-motion discrimination of that same moving grating. Contrast sensitivities from adolescents with ASD were compared to typically-developing adolescents, and also unaffected siblings of individuals with ASD (SIBS). The results revealed significant group differences on P, but not M, pathway processing, with SIBS showing higher chromatic contrast sensitivity than both participants with ASD and TD participants. This atypicality, unique to SIBS, suggests the possible existence of a protective factor in these individuals against developing ASD. The results also revealed impairments in motion perception in both participants with ASD and SIBS, which may be an endophenotype of ASD. This impairment may be driven by impairments in motion detectors and/or by reduced input from neural areas that project to motion detectors, the latter possibility being consistent with the notion of reduced connectivity between neural areas in ASD.

REDUCED CHROMATIC DISCRIMINATION IN  CHILDREN WITH AUTISM SPECTRUM DISORDERS.

Abstract

Atypical perception in Autism Spectrum Disorders (ASD) is well documented (Dakin & Frith, 2005). However, relatively little is known about colour perception in ASD. Less accurate performance on certain colour tasks has led some to argue that chromatic discrimination is reduced in ASD relative to typical development (Franklin, Sowden, Burley, Notman & Alder, 2008). The current investigation assessed chromatic discrimination in children with high-functioning autism (HFA) and typically developing (TD) children matched on age and non-verbal cognitive ability, using the Farnsworth-Munsell 100 hue test (Experiment 1) and a threshold discrimination task (Experiment 2). In Experiment 1, more errors on the chromatic discrimination task were made by the HFA than the TD group. Comparison with test norms revealed that performance for the HFA group was at a similar level to typically developing children around 3 years younger. In Experiment 2, chromatic thresholds were elevated for the HFA group relative to the TD group. For both experiments, reduced chromatic discrimination in ASD was due to a general reduction in chromatic sensitivity rather than a specific difficulty with either red-green or blue-yellow subsystems of colour vision. The absence of group differences on control tasks ruled out an explanation in terms of general task ability rather than chromatic sensitivity. Theories to account for the reduction in chromatic discrimination in HFA are discussed, and findings are related to cortical models of perceptual processing in ASD.

IMPROVEMENT OF VERGENCE MOVEMENTS BY VISION THERAPY DECREASES K-ARS SCORES OF SYMPTOMATIC ADHD CHILDREN.

Abstract

[Purpose] To determine whether the improvement of vergence movements by vision therapy can decrease the K-ARS scores of symptomatic ADHD children. [Methods] Eighty-one out of 1,123 children surveyed using the K-ARS, a parents’-reported questionnaire, led to 16 of these 81 children being showed scores of ≥19, and measurement of binocular function diagnosed as having convergence insufficiency. The 16 children were divided equally into a control group and a vision therapy group. [Results] After vision therapy for 12 weeks, near point convergence (4.38±0.69 cm) significantly neared compared to the near point convergence before vision therapy (11.50±2.28 cm), and both the break point (32.38±2.53 Δ) and recovery point (19.75±2.11 Δ) of near positive fusional vergence significantly improved compared to their values before vision therapy (15.88±2.64 Δ, 6.38±6.70 Δ, respectively). Near exophoria after vision therapy (7.81±2.00 Δ BI) significantly decreased compared to its value before vision therapy (12.00±1.16 Δ BI). The K-ARS scores referring to symptomatic ADHD significantly decreased after vision therapy (17.13±2.84) compared to before vision therapy (23.25±1.49). [Conclusions] Convergence insufficiency symptoms are closely related to symptoms screened for ADHD, and vision therapy to improve vergence movements is an effective method of decreasing the K-ARS scores.

THE RELATIONSHIP BETWEEN CONVERGENCE INSUFFICIENCY  AND ADHD.

Abstract

BACKGROUND:

Children being evaluated for attention deficit hyperactivity disorder (ADHD) often have an eye exam as part of their evaluation. The symptoms of convergence insufficiency (CI) can make it difficult for a student to concentrate on extended reading and overlap with those of ADHD.

METHODS:

A retrospective review of 266 patients with CI presenting to an academic pediatric ophthalmology practice was performed. All patients included were diagnosed with CI by one author (DBG) and evaluated for the diagnosis of ADHD. A computerized review was also performed looking at the converse incidence of CI in patients carrying the diagnosis of ADHD.

RESULTS:

We reviewed 266 charts of patients with CI. Twenty-six patients (9.8%) were diagnosed with ADHD at some time in their clinical course. Of the patients with ADHD and CI, 20 (76.9%) were on medication for ADHD at the time of diagnosis for CI while 6 (23.1%) were either not on medication or the medication was discontinued several months before the diagnosis of CI. The review of computer records showed a 15.9% incidence of CI in the ADHD population.

CONCLUSION:

We report an apparent three-fold greater incidence of ADHD among patients with CI when compared with the incidence of ADHD in the general US population (1.8-3.3%). We also note a seeming three-fold greater incidence of CI in the ADHD population. This may simply represent an association and not be a causative relationship. Until further studies are performed, however, patients diagnosed with ADHD should be evaluated to identify the small subset that may have CI — a condition that responds well to treatment at home.

ADHD AND VISION PROBLEMS IN THE NATIONAL SURVEY OF CHILDREN’S HEALTH.

Abstract

PURPOSE:

To compare the prevalence of attention deficit/hyperactivity disorder (ADHD) in children with normal vision and with vision problems not correctable with glasses or contact lenses (vision problems) as determined by parent report in a nationwide telephone survey.

METHODS:

This cross-sectional study included 75,171 children without intellectual impairment aged 4 to 17 years participating in the 2011 to 2012 National Survey of Children’s Health, conducted by the U.S. Centers for Disease Control and Prevention. Demographic information and information regarding vision and ADHD status were obtained by parent interview. Questions asked whether they had ever been told by a doctor or health care provider that the child had a vision problem not correctable with glasses or contact lenses, ADHD, intellectual impairment, or one of 13 other common chronic conditions of childhood. A follow-up question asked about condition severity. The main outcome measure was current ADHD.

RESULTS:

The prevalence of current ADHD was greater (p < 0.0001) among children with vision problems (15.6%) compared with those with normal vision (8.3%). The odds of ADHD compared with those of children with normal vision were greatest for those with moderate vision problems (odds ratio [OR], 2.6; 95% confidence interval [95% CI], 1.7 to 4.4) and mild vision problems (OR, 1.8; 95% CI, 1.1 to 2.9). Children with severe vision problems had similar odds of ADHD to those of children with normal vision perhaps because of the small numbers in this group (OR, 1.6; 95% CI, 0.8 to 3.1). In multivariable analysis adjusting for confounding variables, vision problems remained independently associated with current ADHD (OR, 1.8; 95% CI, 1.2 to 2.7).

CONCLUSIONS:

In this large nationally representative sample, the prevalence of ADHD was greater among children with vision problems not correctable with glasses or contacts. The association between vision problems and ADHD remains even after adjusting for other factors known to be associated with ADHD.

ACADEMIC BEHAVIORS IN CHILDREN WITH CONVERGENCE INSUFFICIENCY WITH AND WITHOUT PARENT-REPORTED ADHD

Abstract

Purpose

To determine if children with symptomatic Convergence Insufficiency (CI) without the presence of parent reported Attention Deficit Hyperactivity Disorder (ADHD) have higher scores on the academic behavior survey (ABS).

Methods

The Academic Behavior Survey (ABS) is a 6-item survey that evaluates parent concern about school performance and the parents’ perceptions of the frequency of problem behaviors that their child may exhibit when reading or performing schoolwork (such as: difficulty completing work, avoidance, and inattention). Each item is scored on an ordinal scale from 0 (Never) to 4 (Always) with a total score ranging from 0 to 24. The survey was administered to the parents of 212 children 9-17 years old (mean age 11.8 yrs.) with symptomatic CI prior to enrolling into the Convergence Insufficiency Treatment Trial and to 49 children with normal binocular vision (NBV) (mean age 12.5 years). The parents reported whether the child had ADHD and this information was used to divide the symptomatic CI group into the CI with parent-report of ADHD or CI with parent-report of no ADHD groups.

Results

Sixteen percent of the CI group and 6% of the NBV group were classified as ADHD by parental report. An analysis of covariance showed that the total ABS score for the symptomatic CI with parent-report of ADHD group (15.6) was significantly higher than the symptomatic CI with parent-report of no ADHD group (11.7, p=0.001) and the NBV group (8.7, p<0.0001). Children with CI with parent-report of no ADHD scored significantly higher on the ABS than the NBV group (p=0.036).

Conclusions

Children with symptomatic CI with parent-report of no ADHD scored higher on the ABS when compared to children with NBV. Children with parent-report of ADHD or related learning problems may benefit from comprehensive vision evaluation to assess for the presence of CI.

 

INDUCED VERGENCE-ACCOMMODATION CONFLICT REDUCES COGNITIVE PERFORMANCE IN THE STROOP TEST.

Abstract

Interaction mechanisms between cognition and binocular motor control in reading saccades remain unclear. In this study we examine objectively saccades and fixations parameters during the Stroop test, involving three different levels of cognitive demand (reading, color denomination and interference). In addition, we experimentally induce accommodation and vergence conflicts during the different tasks. Twenty-one visually normal subjects (age 20.9 ± 1.45) performed the Stroop test in three different randomized conditions: a control normal viewing condition, a 16Δ base-out prism condition, and a −2.50D spherical lenses condition. Prisms and spherical lenses induced Vergence-Accommodation conflict. Eye movements were recorded with the Eyeseecam video-oculography device. The results show (1) longer fixation duration in the interference task than in the denomination task, and shorter fixation duration in the reading task; (2) a higher interference effect in the conflict induced conditions compared to the control condition; (3) a lower tolerance to prism induced conflict, with a higher destabilization of the binocular motor control of saccades and fixations. This suggests an interplay between vergence accommodation conflict and cognitive load: tolerance to the conflict seems to be lower in the more cognitively demanding interference Stroop task. The results consolidate the link between cognition and high quality of single binocular vision.

PREVALENCE AND CAUSES OF AMBLYOPIA IN AN  ADULT POPULATION.

Abstract

OBJECTIVE:

The study aimed to determine the prevalence, causes, and associations with amblyopia in a defined older population.

DESIGN:

In a population-based study, 3654 persons 49 years of age or older from an area west of Sydney, Australia, underwent a detailed eye examination and history, including objective and subjective refraction, cover testing, and retinal and lens photography. Amblyopia was diagnosed in eyes with reduced best-corrected visual acuity in the absence of any other cause.

RESULTS:

Amblyopia was diagnosed in 118 participants, or 3.2% of the population using a visual acuity criterion of 20/30 or less and 2.9% using a visual acuity criterion of 20/40 or less. Using a two-line visual acuity difference between the eyes, the amblyopia prevalence was 2.6% and 2.5%, respectively, for the above criteria. The underlying amblyogenic causes assessed were anisometropia (50%), strabismus (19%), mixed strabismus and anisometropia (27%), and visual deprivation (4%). The visual acuity of the amblyopic eye was 20/200 or worse (19%), 20/80 to 20/160 (19%), 20/40 to 20/63 (52%), and 20/30 (11%). No statistically significant associations were found between amblyopia and gender or eye affected. The most frequent pattern of strabismus was esotropia, whereas hypermetropia was the most frequent refractive error in amblyopic eyes. The mean age at diagnosis was earlier for strabismic and mixed amblyopia (7.4 years) than for anisometropic amblyopia (12.7 years).

CONCLUSION:

This study has provided prevalence and cases of amblyopia in an older population. Amblyopia is a frequent cause of lifelong unilateral visual impairment.

AMBLYOPIA AND THE BINOCULAR APPROACH TO ITS THERAPY.

Abstract

There is growing evidence that abnormal binocular interactions play a key role in amblyopia. In particular, stronger suppression of the amblyopic eye has been associated with poorer amblyopic eye visual acuity and a new therapy has been described that directly targets binocular function and has been found to improve both monocular and binocular vision in adults and children with amblyopia. Furthermore, non-invasive brain stimulation techniques that alter excitation and inhibition within the visual cortex have been shown to improve vision in the amblyopic eye. The aim of this review is to summarize this previous work and interpret the therapeutic effects of binocular therapy and non-invasive brain stimulation in the context of three potential neural mechanisms; active inhibition of signals from the amblyopic eye, attenuation of information from the amblyopic eye and metaplasticity of synaptic long term potentiation and long term depression.

A NEW BINOCULAR APPROEACH TO THE TREATMENT OF AMBLYOPIA IN ADULTS WELL BEYOND THE CRITICAL PERIOD OF VISUAL DEVELOPMENT.

Abstract

PURPOSE:

The present treatments for amblyopia are predominantly monocular aiming to improve the vision in the amblyopic eye through either patching of the fellow fixing eye or visual training of the amblyopic eye. This approach is problematic, not least of which because it rarely results in establishment of binocular function. Recently it has shown that amblyopes possess binocular cortical mechanisms for both threshold and suprathreshold stimuli.

METHODS:

We outline a novel procedure for measuring the extent to which the fixing eye suppresses the fellow amblyopic eye, rendering what is a structurally binocular system, functionally monocular.

RESULTS:

Here we show that prolonged periods of viewing (under the artificial conditions of stimuli of different contrast in each eye) during which information from the two eyes is combined leads to a strengthening of binocular vision in strabismic amblyopes and eventual combination of binocular information under natural viewing conditions (stimuli of the same contrast in each eye). Concomitant improvement in monocular acuity of the amblyopic eye occurs with this reduction in suppression and strengthening of binocular fusion. Furthermore, in a majority of patients tested, stereoscopic function is established.

CONCLUSIONS:

This provides the basis for a new treatment of amblyopia, one that is purely binocular and aimed at reducing suppression as a first step.

BINOCULAR SUMMATION OF CONTRAST REMAINS INTACT IN  STRABISMIC AMBLYOPIA.

Abstract

PURPOSE:

Strabismic amblyopia is typically associated with several visual deficits, including loss of contrast sensitivity in the amblyopic eye and abnormal binocular vision. Binocular summation ratios (BSRs) are usually assessed by comparing contrast sensitivity for binocular stimuli (sens(BIN)) with that measured in the good eye alone (sens(GOOD)), giving BSR = sens(BIN)/sens(GOOD). This calculation provides an operational index of clinical binocular function, but does not assess whether neuronal mechanisms for binocular summation of contrast remain intact. This study was conducted to investigate this question.

METHODS:

Horizontal sine-wave gratings were used as stimuli (3 or 9 cyc/deg; 200 ms), and the conventional method of assessment (above) was compared with one in which the contrast in the amblyopic eye was adjusted (normalized) to equate monocular sensitivities.

RESULTS:

In nine strabismic amblyopes (mean age, 32 years), the results confirmed that the BSR was close to unity when the conventional method was used (little or no binocular advantage), but increased to approximately radical2 or higher when the normalization method was used. The results were similar to those for normal control subjects (n = 3; mean age, 38 years) and were consistent with the physiological summation of contrast between the eyes. When the normal observers performed the experiments with a neutral-density (ND) filter in front of one eye, their performance was similar to that of the amblyopes in both methods of assessment.

CONCLUSIONS:

The results indicate that strabismic amblyopes have mechanisms for binocular summation of contrast and that the amblyopic deficits of binocularity can be simulated with an ND filter. The implications of these results for best clinical practice are discussed.

NEW INSIGHTS INTO AMBLYOPIA: BINOCULAR THERAPY AND NONINVASIVE BRAIN STIMULATION.

Abstract

The current approach to the treatment of amblyopia is problematic for a number of reasons. First, it promotes recovery of monocular vision but because it is not designed to promote binocularity, its binocular outcomes often are disappointing. Second, compliance is poor and variable. Third, the effectiveness of the treatment is thought to decrease with increasing age. We discuss 2 new approaches aimed at recovering visual function in adults with amblyopia. The first is a binocular approach to amblyopia treatment that is showing promise in initial clinical studies. The second is still in development and involves the use of well-established noninvasive brain stimulation techniques to temporarily alter the balance of excitation and inhibition in the visual cortex.

Effects of strabismic amblyopia and strabismus without amblyopia on visuomotor behavior, I: saccadic eye movements.

Abstract

PURPOSE:

It has previously been shown that anisometropic amblyopia affects the programming and execution of saccades. The aim of the current study was to investigate the impact of strabismic amblyopia on saccade performance.

METHODS:

Fourteen adults with strabismic amblyopia, 13 adults with strabismus without amblyopia, and 14 visually normal adults performed saccades and reach-to-touch movements to targets presented at ± 5° and ± 10° eccentricity during binocular and monocular viewing. Latency, amplitude, and peak velocity of primary and secondary saccades were measured.

RESULTS:

In contrast to visually normal participants who had shorter primary saccade latency during binocular viewing, no binocular advantage was found in patients with strabismus with or without amblyopia. Patients with amblyopia had longer saccade latency during amblyopic eye viewing (P < 0.0001); however, there were no significant differences in saccade amplitude precision among the three groups across viewing conditions. Further analysis showed that only patients with severe amblyopia and no stereopsis (n = 4) exhibited longer latency (which was more pronounced for more central targets; P < 0.0001), and they also had reduced amplitude precision during amblyopic eye viewing. In contrast, patients with mild amblyopia (n = 5) and no stereopsis had normal latency and reduced precision during amblyopic eye viewing (P < 0.001), whereas those with gross stereopsis (n = 5) had normal latency and precision. There were no differences in peak velocity among the groups.

CONCLUSIONS:

Distinct patterns of saccade performance according to different levels of visual acuity and stereoscopic losses in strabismic amblyopia were found. These findings were in contrast to those in anisometropic amblyopia in which the altered saccade performance was independent of the extent of visual acuity or stereoscopic deficits. These results were most likely due to different long-term sensory suppression mechanisms in strabismic versus anisometropic amblyopia.

Effects of strabismic amblyopia on visuomotor behavior: part II. Visually guided reaching.

Abstract

PURPOSE:

To examine the effects of impaired spatiotemporal vision on reaching movements in participants with strabismic amblyopia and to compare their performance to those with strabismus only without amblyopia and to visually normal participants.

METHODS:

Sixteen adults with strabismic amblyopia, 14 adults with strabismus only, and 16 visually normal adults were recruited. Participants executed reach-to-touch movements toward targets presented randomly 5° or 10° to the left or right of central fixation in three viewing conditions: both eyes, monocular amblyopic eye (nondominant eye for participants without amblyopia), and monocular fellow eye (dominant eye for participants without amblyopia). Visual feedback of the target was removed on 50% of the trials at the initiation of reaching.

RESULTS:

Both groups with abnormal binocular vision (strabismic amblyopia and strabismus only) had reach latency, accuracy, and precision comparable to visually normal participants when viewing with both eyes and fellow (dominant) eye. Latencies were significantly delayed by more than 30 ms in all participants with reduced binocularity during amblyopic eye or nondominant eye viewing compared with controls (P < 0.0001). Participants with strabismic amblyopia and negative stereopsis also had reduced reach precision (i.e., increased variability) during amblyopic eye viewing. In contrast, participants with strabismus only and negative stereopsis had comparable precision across all viewing conditions. Participants with strabismus only and those with strabismic amblyopia used a similar motor strategy; regardless of viewing condition, reach peak acceleration was significantly reduced (P < 0.05) and the duration of acceleration phase was extended in comparison with visually normal participants. There were no significant differences for the deceleration phase.

CONCLUSIONS:

Participants with strabismic amblyopia and those with strabismus only attain relatively normal reach accuracy and precision. However, they use a different reach strategy that involves changing the motor plan. A similar compensatory strategy was reported previously in participants with anisometropic amblyopia. Our results provide further support that normal binocular vision during development provides important input for the development of visually guided reaching movements.

Effects of strabismic amblyopia and strabismus without amblyopia on visuomotor behavior: III. Temporal eye-hand coordination during reaching.

Abstract

PURPOSE:

To examine the effects of strabismic amblyopia and strabismus only, without amblyopia, on the temporal patterns of eye-hand coordination during both the planning and execution stages of visually-guided reaching.

METHODS:

Forty-six adults (16 with strabismic amblyopia, 14 with strabismus only, and 16 visually normal) executed reach-to-touch movements toward targets presented randomly 5° or 10° to the left or right of central fixation. Viewing conditions were binocular, monocular viewing with the amblyopic eye, and monocular viewing with the fellow eye (dominant and nondominant viewing for participants without amblyopia). Temporal coordination between eye and hand movements was examined during reach planning (interval between the initiation of saccade and reaching, i.e., saccade-to-reach planning interval) and reach execution (interval between the initiation of saccade and reach peak velocity [PV], i.e., saccade-to-reach PV interval). The frequency and dynamics of secondary reach-related saccades were also examined.

RESULTS:

The temporal patterns of eye-hand coordination prior to reach initiation were comparable among participants with strabismic amblyopia, strabismus only, and visually normal adults. However, the reach acceleration phase of participants with strabismic amblyopia and those with strabismus only were longer following target fixation (saccade-to-reach PV interval) than that of visually normal participants (P < 0.05). This effect was evident under all viewing conditions. The saccade-to-reach planning interval and the saccade-to-reach PV interval were not significantly different among participants with amblyopia with different levels of acuity and stereo acuity loss. Participants with strabismic amblyopia and strabismus only initiated secondary reach-related saccades significantly more frequently than visually normal participants. The amplitude and peak velocity of these saccades were significantly greater during amblyopic eye viewing in participants with amblyopia who also had negative stereopsis.

CONCLUSIONS:

Adults with strabismic amblyopia and strabismus only showed an altered pattern of temporal eye-hand coordination during the reach acceleration phase, which might affect their ability to modify reach trajectory using early online control. Secondary reach-related saccades may provide a compensatory mechanism with which to facilitate the late online control process in order to ensure relatively good reaching performance during binocular and fellow eye viewing.

Effects of Reduced Acuity and Stereo Acuity on Saccades and Reaching Movements in Adults With Amblyopia and Strabismus.

Abstract

Purpose:

Our previous work has shown that amblyopia disrupts the planning and execution of visually-guided saccadic and reaching movements. We investigated the association between the clinical features of amblyopia and aspects of visuomotor behavior that are disrupted by amblyopia.

Methods:

A total of 55 adults with amblyopia (22 anisometropic, 18 strabismic, 15 mixed mechanism), 14 adults with strabismus without amblyopia, and 22 visually-normal control participants completed a visuomotor task while their eye and hand movements were recorded. Univariate and multivariate analyses were performed to assess the association between three clinical predictors of amblyopia (amblyopic eye [AE] acuity, stereo sensitivity, and eye deviation) and seven kinematic outcomes, including saccadic and reach latency, interocular saccadic and reach latency difference, saccadic and reach precision, and PA/We ratio (an index of reach control strategy efficacy using online feedback correction).

Results:

Amblyopic eye acuity explained 28% of the variance in saccadic latency, and 48% of the variance in mean saccadic latency difference between the amblyopic and fellow eyes (i.e., interocular latency difference). In contrast, for reach latency, AE acuity explained only 10% of the variance. Amblyopic eye acuity was associated with reduced endpoint saccadic (23% of variance) and reach (22% of variance) precision in the amblyopic group. In the strabismus without amblyopia group, stereo sensitivity and eye deviation did not explain any significant variance in saccadic and reach latency or precision. Stereo sensitivity was the best clinical predictor of deficits in reach control strategy, explaining 23% of total variance of PA/We ratio in the amblyopic group and 12% of variance in the strabismus without amblyopia group when viewing with the amblyopic/nondominant eye.

Conclusions:

Deficits in eye and limb movement initiation (latency) and target localization (precision) were associated with amblyopic acuity deficit, whereas changes in the sensorimotor reach strategy were associated with deficits in stereopsis. Importantly, more than 50% of variance was not explained by the measured clinical features. Our findings suggest that other factors, including higher order visual processing and attention, may have an important role in explaining the kinematic deficits observed in amblyopia.

INTERVENTIONS FOR INFANTILE ESOTROPIA

Abstract

BACKGROUND:

Infantile esotropia (IE) is the inward deviation of the eye. Various aspects of the clinical management of IE are unclear; mainly, the most effective type of intervention and the age at intervention.

OBJECTIVES:

The objective of this review was to assess the effectiveness of various surgical and non-surgical interventions for IE and to determine the significance of age at treatment with respect to outcome.

SEARCH METHODS:

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 5), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE, (January 1950 to June 2013), EMBASE (January 1980 to June 2013), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to June 2013), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 10 June 2013. We manually searched the conference proceedings of the European Strabismological Association (ESA) (1975 to 1997, 1999 to 2002), International Strabismological Association (ISA) (1994) and American Academy of Paediatric Ophthalmology and Strabismus meeting (AAPOS) (1995 to 2003). Efforts were made to contact researchers who are active in the field for information about further published or unpublished studies.

SELECTION CRITERIA:

We included randomised trials comparing any surgical or non-surgical intervention for infantile esotropia.

DATA COLLECTION AND ANALYSIS:

Each review author independently assessed study abstracts identified from the electronic and manual searches.

MAIN RESULTS:

No studies were found that met our selection criteria and therefore none were included for analysis.

AUTHORS’ CONCLUSIONS:

The main body of literature on interventions for IE are either retrospective studies or prospective cohort studies. It has not been possible through this review to resolve the controversies regarding type of surgery, non-surgical intervention and age of intervention. There is clearly a need for good quality trials to be conducted in these areas to improve the evidence base for the management of IE.

INTERVENTIONS FOR INTERMITTENT EXOTROPIA

Abstract

BACKGROUND:

The clinical management of intermittent exotropia has been discussed extensively in the literature, yet there remains a lack of clarity regarding indications for intervention, the most effective form of treatment and whether or not there is an optimal time in the evolution of the disease at which any treatment should be carried out.

OBJECTIVES:

The objective of this review was to analyse the effects of various surgical and non-surgical treatments in randomised trials of participants with intermittent exotropia, and to report intervention criteria and determine the significance of factors such as age with respect to outcome.

SEARCH METHODS:

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library, Issue 4, 2012), MEDLINE (January 1966 to May 2012), EMBASE (January 1980 to May 2012), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to May 2012), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 4 May 2012. We are no longer searching the UK Clinical Trials Gateway (UKCTG) for this review. We manually searched the British Orthoptic Journal up to 2002, and the proceedings of the European Strabismological Association (ESA), International Strabismological Association (ISA) and American Academy of Paediatric Ophthalmology and Strabismus meeting (AAPOS) up to 2001. We contacted researchers who are active in the field for information about further published or unpublished studies.

SELECTION CRITERIA:

We included randomised controlled trials of any surgical or non-surgical treatment for intermittent exotropia.

DATA COLLECTION AND ANALYSIS:

Each review author independently assessed study abstracts identified from the electronic and manual searches. Author analysis was then compared and full papers for appropriate studies were obtained.

MAIN RESULTS:

We found one randomised trial that was eligible for inclusion. This trial showed that unilateral surgery was more effective than bilateral surgery for correcting the basic type of intermittent exotropia.

AUTHORS’ CONCLUSIONS:

The available literature consists mainly of retrospective case reviews, which are difficult to reliably interpret and analyse. The one randomised trial included found unilateral surgery more effective than bilateral surgery for basic intermittent exotropia. However, across all identified studies, measures of severity and thus criteria for intervention are poorly validated, and there appear to be no reliable natural history data. There is therefore a pressing need for improved measures of severity, a better understanding of the natural history and carefully planned clinical trials of treatment to improve the evidence base for the management of this condition.

INTERVENTIONS FOR DISSOCIATED VERTICAL DEVIATION

Abstract

BACKGROUND:

The term «strabismus» describes misalignment of the eyes. One or both eyes may deviate inward, outward, upward, or downward. Dissociated vertical deviation (DVD) is a well-recognized type of upward drifting of one or both eyes, which can occur in children or adults. DVD often develops in the context of infantile- or childhood-onset horizontal strabismus, either esotropia (inward-turning) or exotropia (outward-turning). For some individuals, DVD remains controlled and can only be detected during clinical testing. For others, DVD becomes spontaneously «manifest» and the eye drifts up of its own accord. Spontaneously manifest DVD can be difficult to control and often causes psychosocial concerns. Traditionally, DVD has been thought to be asymptomatic, although some individuals have double vision. More recently it has been suggested that individuals with DVD may also suffer from eyestrain. Treatment for DVD may be sought either due to psychosocial concerns or because of these symptoms. The standard treatment for DVD is a surgical procedure; non-surgical treatments are offered less commonly. Although there are many studies evaluating different management options for the correction of DVD, a lack of clarity remains regarding which treatments are most effective.

OBJECTIVES:

The objective of this review was to determine the effectiveness and safety of various surgical and non-surgical interventions in randomized controlled trials of participants with DVD.

SEARCH METHODS:

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2015, Issue 8), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to August 2015), EMBASE (January 1980 to August 2015), PubMed (1948 to August 2015), Latin American and Caribbean Health Sciences Literature Database (LILACS) (1982 to August 2015), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com) (last searched 3 February 2014), ClinicalTrials.gov (www.clinicaltrials.gov), and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 3 August 2015.

SELECTION CRITERIA:

We included randomized controlled trials (RCTs) of surgical and non-surgical interventions for the correction of DVD.

DATA COLLECTION AND ANALYSIS:

We used standard procedures expected by Cochrane. Two review authors independently completed eligibility screening, data abstraction, ‘Risk of bias’ assessment, and grading of the evidence.

MAIN RESULTS:

We found four RCTs eligible for inclusion in this review (248 eyes of 151 participants between the ages of 6 months to 22 years). All trials were assessed as having unclear risk of bias overall due to insufficient reporting of study methods. One trial was conducted in Canada and compared anteriorization of the inferior oblique muscle with resection versus anteriorization of the inferior oblique muscle alone; one in the USA compared superior rectus recession with posterior fixation suture versus superior rectus recession alone; and two in the Czech Republic compared anteriorization of the inferior oblique muscle versus myectomy of the inferior oblique muscle.Only one trial reported data that allowed analysis of the primary outcome for this review, the proportion of participants with treatment success. The difference between inferior oblique anteriorization plus resection versus inferior oblique anteriorization alone was uncertain when measured at least four months postoperatively (risk ratio 1.13, 95% confidence interval 0.60 to 2.11, 30 participants, very low-quality evidence). Three trials measured the magnitude of hyperdeviation, but did not provide sufficient data for analysis. All four trials reported a relatively low rate of adverse events; hypotropia, limited elevation, and need for repeat surgery were reported as adverse events associated with some of the surgical interventions. No trials reported any other secondary outcome specified for our review.

AUTHORS’ CONCLUSIONS:

The four trials included in this review assessed the effectiveness of five different surgical procedures for the treatment of DVD. Nevertheless, insufficient reporting of study methods and data led to methodological concerns that undermine the conclusions of all studies. There is a pressing need for carefully executed RCTs of treatment for DVD in order to improve the evidence for the optimal management of this condition.

BOTULINUM TOXIN FOR THE TREATMENT OF STRABISMUS

Abstract

BACKGROUND:

The use of botulinum toxin as an investigative and treatment modality for strabismus is well reported in the medical literature. However, it is unclear how effective it is in comparison to other treatment options for strabismus.

OBJECTIVES:

The primary objective was to examine the efficacy of botulinum toxin therapy in the treatment of strabismus compared with alternative conservative or surgical treatment options. This review sought to ascertain those types of strabismus that particularly benefit from the use of botulinum toxin as a treatment option (such as small angle strabismus or strabismus with binocular potential, i.e. the potential to use both eyes together as a pair). The secondary objectives were to investigate the dose effect and complication rates associated with botulinum toxin.

SEARCH METHODS:

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 6), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to July 2016), Embase (January 1980 to July 2016), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to July 2016), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov), and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 11 July 2016. We handsearched the British and Irish Orthoptic Journal, Australian Orthoptic Journal, proceedings of the European Strabismological Association (ESA), International Strabismological Association (ISA) and International Orthoptic Association (IOA) (www.liv.ac.uk/orthoptics/research/search.htm) and American Academy of Paediatric Ophthalmology and Strabismus meetings (AAPOS). We contacted researchers who are active in this field for information about further published or unpublished studies.

SELECTION CRITERIA:

We included randomised controlled trials (RCTS) of any use of botulinum toxin treatment for strabismus.

DATA COLLECTION AND ANALYSIS:

Two review authors independently selected studies and extracted data. We used standard methods expected by Cochrane and assessed the certainty of the evidence using GRADE. We defined ocular alignment as an angle of deviation of less than or equal to 10 prism dioptres.

MAIN RESULTS:

Six RCTs were eligible for inclusion. We judged the included studies as at a mixture of low, unclear and high risk of bias. We did not consider any of the included studies as at low risk of bias for all domains.Two trials conducted in Spain (102 people, number of eyes not specified) compared botulinum toxin with surgery in children that required retreatment for acquired or infantile esotropia. These two studies provided low-certainty evidence that children who received botulinum toxin may have a similar or slightly reduced chance of achieving ocular alignment (pooled risk ratio (RR) 0.91, 95% confidence interval (CI) 0.71 to 1.16), binocular single vision (RR 0.88, 95% CI 0.63 to 1.23), sensory fusion (RR 0.88, 95% CI 0.63 to 1.23) and stereopsis (RR 0.86, 95% CI 0.59 to 1.25) compared with children who received surgery. One trial from Canada compared botulinum toxin with surgery in 30 adults (30 eyes) with horizontal strabismus and reported a reduced chance of ocular alignment with botulinum toxin (RR 0.38, 95% CI 0.17 to 0.85; low-certainty evidence).One trial in the UK suggested that botulinum toxin may result in a similar or slightly improved chance of ocular alignment in people with acute onset sixth nerve palsy compared with observation (RR 1.19, 95% CI 0.96 to 1.48; 47 participants, low-certainty evidence).Very low-certainty evidence from one trial from Brazil suggested that adjuvant botulinum toxin in strabismus surgery may increase the chances of ocular alignment compared with strabismus surgery alone (RR 1.83, 95% CI 0.41 to 8.11; 23 participants).One trial from China of 47 participants (94 eyes) suggested that people receiving botulinum toxin combined with sodium hyaluronate may have a similar or slightly reduced chance of achieving ocular alignment compared with botulinum toxin alone (RR 0.81, 95% CI 0.36 to 1.82; low-certainty evidence).Reported complications in people given botulinum toxin in the included trials included ptosis (range 9% to 41.66%) and vertical deviation (range 8.3% to 18.51%). Ptosis occurred less frequently when treated with botulinum toxin combined with sodium hyaluronate compared to botulinum toxin alone.

AUTHORS’ CONCLUSIONS:

Most published literature on the use of botulinum toxin in the treatment of strabismus consists of retrospective studies, cohort studies or case reviews. Although these provide useful descriptive information, clarification is required as to the effective use of botulinum toxin as an independent treatment modality. Six RCTs on the therapeutic use of botulinum toxin in strabismus, graded as low and very low-certainty evidence, have shown varying responses. These include a lack of evidence for effect of botulinum toxin on reducing visual symptoms in acute sixth nerve palsy, poor response in people with horizontal strabismus without binocular vision, similar or slightly reduced achievement of successful ocular alignment in children with esotropia and potential increased achievement of successful ocular alignment where surgery and botulinum toxin are combined. Further high quality trials using robust methodologies are required to compare the clinical and cost effectiveness of various forms of botulinum toxin (e.g. Dysport, Xeomin, etc), to compare botulinum toxin with and without adjuvant solutions and to compare botulinum toxin to alternative surgical interventions in strabismus cases with and without potential for binocular vision.

ORIGINS OF STRABISMUS AND LOSS OF BINOCULAR VISION

Abstract

Strabismus is a frequent ocular disorder that develops early in life in humans. As a general rule, it is characterized by a misalignment of the visual axes which most often appears during the critical period of visual development. However other characteristics of strabismus may vary greatly among subjects, for example, being convergent or divergent, horizontal or vertical, with variable angles of deviation. Binocular vision may also vary greatly. Our main goal here is to develop the idea that such «polymorphy» reflects a wide variety in the possible origins of strabismus. We propose that strabismus must be considered as possibly resulting from abnormal genetic and/or acquired factors, anatomical and/or functional abnormalities, in the sensory and/or the motor systems, both peripherally and/or in the brain itself. We shall particularly develop the possible «central» origins of strabismus. Indeed, we are convinced that it is time now to open this «black box» in order to move forward. All of this will be developed on the basis of both presently available data in literature (including most recent data) and our own experience. Both data in biology and medicine will be referred to. Our conclusions will hopefully help ophthalmologists to better understand strabismus and to develop new therapeutic strategies in the future. Presently, physicians eliminate or limit the negative effects of such pathology both on the development of the visual system and visual perception through the use of optical correction and, in some cases, extraocular muscle surgery. To better circumscribe the problem of the origins of strabismus, including at a cerebral level, may improve its management, in particular with respect to binocular vision, through innovating tools by treating the pathology at the source.

Rates of Reoperation and Abnormal Binocularity Following Strabismus Surgery in Children.

Abstract

Purpose

To determine predictors of reoperation and abnormal binocularity outcomes (including amblyopia and diplopia) following pediatric strabismus surgery.

Design

Retrospective cross-sectional study.

Methods

Setting: Review of a national insurance database. Study population: Children under age 18 years having strabismus procedures between 2007 and 2013. Interventions: Adjustable or fixed suture strabismus surgery, or botulinum toxin injection. Outcome measures: Reoperation or diagnosis of abnormal binocularity in the first postoperative year.

Results

Of 11,115 children having strabismus procedures, 851 (7.7%) underwent reoperation. The reoperation rate was 7.4% for fixed suture surgeries, 9.6% for adjustable suture surgeries (p=0.18), and 44.9% for botulinum injections (p<0.001). Age under 2 years was associated with higher reoperation and abnormal binocularity rates (p<0.001). For horizontal strabismus, the postoperative abnormal binocularity rate was 12.8% for fixed suture surgery and 26.5% for botulinum injection (p=0.005). Reoperation rates tended to be higher with adjustable sutures (odds ratio [OR] 1.69, 95% confidence interval [CI] 0.94 to 3.03, p=0.08), or botulinum toxin injection (OR 10.36, 95% CI 5.75 to 18.66, p<0.001) and lower with 3- or 4-muscle surgery (p=0.001). Esotropia, hyperopia, and botulinum injection were independently associated with higher rates of postoperative abnormal binocularity (p<=0.005). For vertical surgeries, predictors of reoperation were adjustable suture use (OR 2.51, p=0.10) and superior oblique surgery (OR 2.36, p<0.001).

Conclusions

Adjustable sutures were not associated with a lower reoperation rate in children. Younger age, esotropia, hyperopia, and botulinum injection were associated with postoperative abnormal binocularity. Superior oblique surgery and botulinum injection were associated with higher rates of reoperation.

Reoperation following strabismus surgery among Medicare beneficiaries: Associations with geographic region, academic affiliation, surgeon volume, and adjustable suture technique.

Abstract

Purpose:

The objective of this study was to determine the associations of strabismus surgery reoperation rates in a large national database of provider payments with geographic region, practice type and volume, and the availability of adjustable suture technique.

Methods:

Fee-for-service payments to providers for medicare beneficiaries having strabismus surgery between 2012 and 2015 were retrospectively analyzed to identify reoperations in the same calendar year. The adjustable-suture technique was considered to be available to the patient if the patient’s surgeon billed for adjustable sutures. Predictors of reoperation in the same calendar year were determined by multivariable logistic regression.

Results:

Availability of the adjustable suture technique was not associated with reoperation rate in multivariable analysis among 5971 patients having horizontal muscle surgery (odds ratio, [OR] 0.86, P = 0.29), 2840 patients having vertical muscle surgery (OR 0.98, P = 0.93), or 1199 patients having surgery with scarring or restriction (OR 0.86, P = 0.61). For horizontal surgery, the reoperation rate was higher in academic practices (OR 1.67), as compared with community practices, and in the South (OR 2.85) and West (OR 1.92, all P < 0.001). The reoperation rate was unchanged with surgeons in the lowest-quartile of surgical volume. Among surgeons paid for horizontal surgery, 45% of surgeons in the Northeast, the West, or Florida coded for adjustable sutures, compared with 8% of surgeons elsewhere (P < 0.001).

Conclusion:

The availability of the adjustable-suture technique was not associated with reoperation rate after strabismus surgery in this large national database. Having surgery by a lower-volume surgeon was not associated with a higher reoperation rate. The reoperation rate was higher when surgery was conducted in an academic practice, or in certain regions of the country. Adjustable sutures are largely a bicoastal practice.

  • Optometric Management of Learning-related Vision Problems – Michael W. Rouse & Mitchell Scheiman;
  • Vision Rehabilitation Multidisciplinary Care of the Patient Following Brain Injury – Penelope S. Suter &  Lisa H. Harvey
  • Pickwell’s Binocular Vision Anomalies – Bruce J. W. Evans
  • The Neurology Of Eye Movements – R. John Leigh &  David S. Zee
  • Visual Perception: A Clinical Orientation – Steven Schwartz 
  • A vision of the brain – Semir Zeki
  • Fixing My Gaze: A Scientist’s Journey Into Seeing in Three Dimensions – Susan R. Barry

VISION THERAPY FOR BINOCULAR DYSFUNCTION POST BRAIN INJURY.

Abstract

PURPOSE:

To prospectively evaluate the effectiveness of home-based computer vergence therapy for the treatment of binocular vision disorders in adults at least 3 months after an acquired brain injury.

METHODS:

Eligibility criteria included presence of binocular dysfunction characterized by receded near point of convergence (≥6 cm break), insufficient positive fusional vergence at near (failing Sheard’s criterion or <15△ blur or break), insufficient negative fusional vergence at near (<12△ blur or break), and/or reduced vergence facility at near (<15 cycles per minute with 12△BO/3△BI). Participants were prescribed 12 weeks of home-based computer vergence therapy. Phoria (cover test), negative fusional vergence, positive fusional vergence, near point of convergence, vergence facility, and symptoms (convergence insufficiency symptom survey [CISS]) were assessed at baseline and after 4, 8, and 12 weeks of prescribed therapy. ANOVA was used to evaluate change in each measure. Percentage successful was also determined.

RESULTS:

Nineteen participants were enrolled (mean age 45.4 ± 12.9 years); six participants were lost to follow-up. Baseline findings were orthophoria at distance, 7.2△ exophoria at near, near point of convergence break = 17.5 cm, near point of convergence recovery = 21.8 cm, negative fusional vergence = 12.3△, positive fusional vergence blur = 8.4△, vergence facility = 3.9 cycles per minute, and CISS = 32.1. ANOVA showed a statistically significant improvement for near point of convergence break (p = 0.002) and recovery (p < 0.001), positive fusional vergence blur (p < 0.0001), break (p < 0.0001), and recovery (p < 0.0001), negative fusional vergence blur (p = 0.037), break (p = 0.003), and recovery (p = 0.006), vergence facility (p < 0.0001), and CISS (p = 0.0001). The percentage of patients who were classified as «successful» or «improved» was 69% for near point of convergence (<6 cm or decrease of ≥4 cm), 77% for positive fusional vergence (>15△ and passing Sheard’s criterion or increase of ≥10△), 77% for negative fusional vergence (≥12△ or increase of ≥6△), 62% for positive fusional vergence and near point of convergence composite, and 92% for vergence facility (15 cycles per minute or increase of 3 cycles per minute).

CONCLUSIONS:

The majority of participants who completed the study experienced meaningful improvements in signs and symptoms.

OCULOMOTOR NEUROREHABILITATION FOR READING IN MILD TRAUMATIC BRAIN INJURY (mTBI): AN INTEGRATIVE APPROACH.

Abstract

BACKGROUND:

Considering the extensive neural network of the oculomotor subsystems, traumatic brain injury (TBI) could affect oculomotor control and related reading dysfunction.

OBJECTIVE:

To evaluate comprehensively the effect of oculomotor-based vision rehabilitation (OBVR) in individuals with mTBI.

METHODS:

Twelve subjects with mTBI participated in a cross-over, interventional study involving oculomotor training (OMT) and sham training (ST). Each training was performed for 6 weeks, 2 sessions a week. During each training session, all three oculomotor subsystems (vergence/accommodation/version) were trained in a randomized order across sessions. All laboratory and clinical parameters were determined before and after OMT and ST. In addition, nearvision-related symptoms using the Convergence Insufficiency Symptom Survey (CISS) scale and subjective visual attention using the Visual Search and Attention Test (VSAT) were assessed.

RESULTS:

Following the OMT, over 80% of the abnormal parameters significantly improved. Reading rate, along with the amplitudes of vergence and accommodation, improved markedly. Saccadic eye movements demonstrated enhanced rhythmicity and accuracy. The improved reading-related oculomotor behavior was reflected in reduced symptoms and increased visual attention. None of the parameters changed with ST.

CONCLUSIONS:

OBVR had a strong positive effect on oculomotor control, reading rate, and overall reading ability. This oculomotor learning effect suggests considerable residual neuroplasticity following mTBI.

NEUROVISUAL REHABILITATION: RECENT DEVELOPMENTS AND FUTURE DIRECTIONS.

VISION CONCERNS AFTER MILD TRAUMATIC BRAIN INJURY.

Abstract

Mild traumatic brain injury (mTBI) can manifest with visual dysfunction including deficits in accommodation, vergence movements, versions, and field of vision as well increased photosensitivity and a decline in ocular and overall health. Patients with incomitant strabismus should be referred to an ophthalmologist for intervention. Patients with mTBI who experience photosensitivity, or deficits in accommodation, versions, vergences, or field of vision may benefit from vision rehabilitation. These therapies may include spectacles with tinting and a variety of prism combinations. Patients with chronic visual dysfunction following mTBI may benefit from occupational, vestibular, cognitive, and other forms of physical therapy.