Ophthalmic lenses are prescribed to compensate for an excess or lack of eyeball strength so as to provide a clear image. They can therefore be used to compensate refractive errors such as myopia, hypermetropia, astigmatism and presbyopia (refractive lens).
Lenses are made using different materials: glass, polycarbonate and plastic. Glass lenses have fallen into disuse due to the risk of breakage and injuries and also because of their weight. The strongest lenses are made of polycarbonate, but they are highly prone to scratching and not the best optically. The most widely used are, therefore, plastic lenses. It is currently possibly to manufacture lenses of practically any strength, different thicknesses, and with numerous treatments (anti-reflective, hardened, etc.) and multiple filters and colorings.
Lenses can be:
- Monofocal, single strength (for single-distance focusing).
- Bifocal, two strengths (for dual-distance focusing).
- Multifocal, several strengths (for multiple-distance focusing).
- Progressive, “infinite” strengths (for all-distance focusing).
The type of power can be:
- Positive: used to compensate hypermetropia; they help relax accommodation because “they replace” the function of the natural lens of the eye. This is why positive lenses are also used for compensating presbyopia. They help reduce convergence strength.
- Negative: used to compensate myopia; they stimulate accommodation and increase or stimulate convergence.
The purpose of the lens is not to compensate any refractive defect, but to modify accommodation, namely the “effort” the visual system has to make to maintain the single image, the appreciation of object size, spatial localisation and, generally, our perception of our surroundings.
Despite being low-strength lenses, they can make great changes to our visual processing.
In many cases we use bifocal glasses, namely fitted with dual-strength lenses, for seeing objects close up and in the distance. These lenses provide focal balance from near to far and vice versa.
LContact lenses enable the correction of the patient’s refractive error (myopia, hypermetropia and/or astigmatism) without the need to wear glasses. Their use offers innumerable benefits, such as improved esthetics, the lower risk when playing of sports, increased lateral (peripheral) vision and a visual experience similar to how we would see if we did not have to wear glasses. Adding all of this to the existence of a very wide range of materials and frequency of replacement: daily, monthly, permanent, etc., means that very few people are unsuited to wearing contact lenses.
Your optometrist will let you know the best contact lenses for you and if there is any contraindication.
For patients with:
- Lazy eye (amblyopia)
- Difference of strength between one eye and the other (anisometropia)
Using contact lenses is not just another option. Functionally speaking it is the most recommended choice, whether we are at the start of a Vision Therapy programme or we are simply looking for the best optical solution.
The fact that technology has advanced so much means that we now have a choice of materials that can be adapted to suit practically any age, even babies. These are, of course, special adaptations which, in the hands of a good professional and adhering to the recommended advice and check-ups, carry very few risks. Furthermore, the use of contact lenses from very early ages helps to improve:
- Vision: they standardise the size of images and improve lateral (peripheral) vision.
- Vision Therapy: : with strabismus, lazy eye (amblyopia), strength differences between one eye and the other (anisometropia) and myopia.
- Interaction with other children: playing sports without the risk of breaking their glasses, greater independence and higher self-esteem.
- Level of responsibility.
An optical prism is a lens. When looking through it, an apparent displacement of the object being focused on is noticeable.
In the same way as with Refractive Lenses, Prisms can be used for both compensatory and behavioural purposes (Yoked prisms).
Compensatory Prisms are used:
- When patients find it difficult to align their visual axes, which results in visual discomforts such as headaches, dizziness, diplopia (horizontal or vertical double vision).
- In STRABISMUS sufferers they provide a stimulus that makes patients change their binocular vision or compensate for the deviation of the strabismic eye.
Postural Prisms are used to modify spatial perception by getting patients to change not only to their visual and bodily posture, but also make changes in their general behaviour.
This group includes Yoked Prisms, thus named because the strength and base prescribed are the same in both eyes. They are extensively used for treating binocular vision problems such as insufficient and excess convergence and divergence, accommodative problems like accommodative insufficiency and excess and recent myopias. Furthermore, they are extensively used to treat Brain Injury and Head Trauma, where they help to modify head, body and gait posture.
The strength of the prism depends on the effect one wishes to produce, although it is true that on numerous occasions prisms with strengths as low as 0.5 produce surprising effects.
When treating Brain Injury and Head Traumas, as well as compensating to eliminate diplopia and strabismus, prism strength may be significantly increa.
Controlling Myopia: Orthokeratology. What is it?
Orthokeratology is the temporary and reversible modification of corneal curvature. This is achieved via the night time use of semi-rigid lenses especially designed for sleeping in. In this way we manage to reduce or eliminate the patients’ myopia and/or astigmatism and thereby enable them to see clearly during the day without the need to wear glasses or contact lenses. Materials are also beginning to appear on the market that enable the reduction of hypermetropia.
When is it recommended?
Anybody who wishes to (or must, for professional or recreational reasons) do away with glasses and/or contact lenses can benefit from orthokeratology treatment as there is no age limit. Moreover, as regards controlling myopia, various studies have shown its effectiveness in reducing the progression of the myopia and that is why it is usually recommended in these cases.
With which prescriptions does it work?
There are currently designs on the market that enable the reduction of up to 6 diopters of myopia and 3 diopters of astigmatism. Generally it works very well with myopias of up to 3-4 diopters and with astigmatisms of up to 1 diopter. All the same, orthokeratology is a treatment that involves other variables, in addition to strength, such as the initial shape of the cornea (degree of flattening and geometry) and its malleability. It is for this reason that a feasibility study will enable your optometrist to inform you of the chances of success in your case.
Orthokeratology vs. Operation
Orthokeratology provides a series of advantages over Lasik eye surgery:
- It is reversible: if patients stop using the lenses, their corneas return to their initial condition.
- There is no age limit.
- The strength of the lens can be adjusted simply by changing it.
- Cornea thickness is not a factor.
What is Syntonic Phototherapy?
It is an optometric vision treatment that uses the application of light through various colored filters at certain specific frequencies. It stimulates the biochemistry of the brain, via the visual system, through the connection of the retina (the Magno and Parvocellular Systems) with brain centres such as the Hypothalamus, the Autonomic Nervous System (Sympathetic and Parasympathetic).
The majority of the current therapeutic techniques used in Syntonics are based on the work carried out by Dr Harry Riley Spitler, who graduated in Optometry and Medicine in 1920-30 and founded the College of Syntonic Optometry (www.syntonicphototherapy.com). He discovered that many systemic, mental, emotional and visual disorders were caused by unbalances in the nervous and endocrine systems. Clinical studies subsequently undertaken by Doctors Robert M. Kaplan (1983) and Jacob Liberman (1986) confirmed that a large number of children with learning difficulties suffered from reduced sensitivity of their peripheral vision. They showed that peripheral vision and visual skills, memory, behavior, mood, general performance and academic achievement all improved during and after phototherapy.
The optometrist carries out an initial study in which a visual field for each eye is included by assessing the balance of the Visual Focal System (focus, accommodation) and the Peripheral Visual System (binocular system), and as a result of this balance, the percentage of receptive visual field used. The decision regarding which treatment to use in each case is based on the results.
A balance (harmony) between the Sympathetic and Parasympathetic System is achieved, for example, the pupil contracts and dilates in a more appropriate manner.
This is a passive therapy, meaning that patients perform no exercises, but must only be aware of the light they receive via the instrument. Both eyes are stimulated at once.
How is it done?
It is carried out at the practice using an instrument fitted with a number of coloured filters that are shone at determined frequencies or at home using another piece of apparatus fitted with colored filters, with both devices being approved by the College of Syntonic Optometry.
- In the office: a daily session from Monday to Friday for 4 weeks (a minimum of 20 sessions). The visual field is reviewed and an optometric examination is performed every week.
- Therapy at home: a daily session between 4 and 7 days a week (a minimum of 20 sessions). The visual field is reviewed and an optometric examination is performed every week.
How long does it last?
Initially only 20 sessions are prescribed Some patients might need more sessions, but this is unusual.
Can it be combined with other therapies?
Yes, it can be combined with any other therapy. Syntonic Phototherapy is a treatment that acts at a basal level. This does not make it any less necessary and intense, but it is extremely commonplace that after it has been administered alone it is combined with Vision-Cognitive Therapy in order to finish off consciously developing and automating the visual skills acquired.
Syntonic Therapy can be used either as the primary treatment or to support other therapies to help improve strabismus, amblyopia, accommodative or convergence problems, asthenopia, attention deficit, learning difficulties, dyslexia, visual field constrictions associated with ocular stress, oculomotor disorders, among others.
Which skills can be improved by following a Syntonic Phototherapy programme?
- ACCOMMODATION. Accommodation is the ability of the eye to focus (see clearly) at any particular distance. Syntonic Phototherapy balances each eye’s ability to focus and improves effective and sustained binocular focus (using both eyes simultaneously) at any distance.
- EYE MOVEMENTS.Ocular motricity is the capacity to move one’s eyes smoothly and precisely to follow a moving object, read text or change one’s gaze from one object to another (blackboard to desktop, paper to computer screen). There are two types of movement:
- Pursuit: for following a moving object
- Saccadic: for jumping precisely from one object to another
Syntonic Phototherapy stimulates the peripheral retina (Magnocellular System) by getting patients to move their eyes smoothly and precisely without effort and thereby improving reading speed and comprehension and academic and sporting performance.
- BINOCULARITY. Binocularity is the ability to use both eyes simultaneously in a precise and coordinated manner to provide comfortable vision. To achieve this, both eyes must possess similar skills in order to work together as one. By simultaneously stimulating both eyes, Syntonic Phototherapy manages to strengthen their coordinated work and, in so doing, improve three-dimensionality.
What is Vision Therapy?
The concept of Vision Therapy as we Behavioural Optometrists understand it goes far beyond what could be considered “gymnastics for the eyes”. It is a global, holistic concept.
Based on the results obtained from the Optometric Examination regarding the patients’ Perception and Processing of Visual Information and their learning, academic, occupational or recreational needs, the optometrist prepares a customised program of vision therapy procedures aimed at developing and strengthening their visual skills to the maximum and integrating these skills with all senses: hearing, vestibular, proprioception, etc. so as to change the way they use their visual system and thereby improve their academic, occupational and/or sporting performance as well as eliminating or reducing symptoms. In other words, we not only create new neuronal connections, but also a new way of seeing.
Having practiced the vision therapy procedures by the end of it we will have automated and integrated these changes and these will now form part of the patient without anything having to be done to maintain them and without fear of the problems reappearin.
How is this done?
In order to make these changes patients and their parents (in the case of children) must be fully committed throughout both parts of the programme:
- In the office: at least once a week (once a fortnight in some cases) the treatment consists of 45- to 60-minute sessions of specific nvision therapy procedures. As the program progresses the level gradually increases and those done at home are reviewed in order to change them if needed and make sure they are being done correctly.
- Therapy at home: a series of daily 20- to 25-minute procedures designed to automate the changes. These exercises will be modified in line with the progress being made by the patient.
How long does it last?
The length of a program can vary a great deal depending on the problem to be solved and the objectives to be achieved. Once the initial examination has been carried out, a diagnosis has been made and the objectives of the Therapy have been established, the optometrist will then be able to provide a rough idea of the duration of the programme. Furthermore, assessments will be undertaken throughout the programme to evaluate the patient’s progress and the initial estimates may be adjusted according to what is observed.
Can Vision Therapy be combined with other therapies?
In some cases the optometrist might consider the complementary involvement of other professionals such as osteopaths, hearing specialists, allergists, homeopaths, etc. to be necessary. The active involvement of each professional or simultaneity of treatments will be prioritised depending on the severity of the problem.
Which skills can a Behavioural Vision Therapy programme improve?
- ACCOMMODATION. . Accommodation is the eye’s ability to focus (see clearly) at any particular distance. An efficient visual system must include:
- Good focusing flexibility for making near-far and far-near focal changes both quickly and efficiently.
- Amplitude of accommodation to be able to perform close-up visual tasks for long periods of time without getting tired.
When our brain does not send the appropriate order, the musculature used for working in this way does not contract or relax sufficiently and the following symptoms may appear:
- Blurred vision.
- Visual fatigue or headaches while or after reading/writing.
- An increase in the time needed to copy from the blackboard.
- Avoidance of close-up work.
- Reduced reading comprehension.
Vision Therapy includes exercises designed to balance out the focusing ability of each eye and obtain effective and sustained binocular focus (using both eyes at the same time) at any distance.
- EYE MOVEMENTS. Ocular motricity is the ability to move one’s eyes smoothly and precisely to follow a moving object, read text or change one’s gaze from one object to another (blackboard to desktop, paper to computer screen). There are two types of movement:
- Pursuit: for following a moving object.
- Saccadic: for jumping precisely from one object to another.
Well integrated eye movements provide speed and accuracy for changing lines while reading, for altering one’s gaze between the blackboard and the desktop and are essential when practicing those sports that require skills of this type.
Oculomotor Control is closely related with Remaining Attentive, Divided Attention (the ability to perform several activities simultaneously or multitask) and the skill of being able to filter information to be able to maintain the appropriate level of attention.
Ocular motricity problems are very common especially in children with learning and attention deficit problem. The associated symptoms are the following:
- Using a finger as a marker while reading
- Losing one’s place when reading
- Making mistakes when copyi
- Omitting words when reading
- Reading slowly
- Reduced reading comprehension
- Difficulty in hitting and catching a ball
Vision Therapy is used to help patients move their eyes smoothly and accurately without effort, thereby improving their reading speed and comprehension and academic and sporting performance.
- BINOCULARITY. Binocularity is the ability to use both eyes simultaneously in a precise and coordinated manner to provide comfortable vision. To achieve this, both eyes must possess similar skills in order to work together as one. Inadequate binocular control can result in the following symptoms:
- The deviation of one or both eyes (strabismus)
- Double vision
- Reduced 3-dimensional vision (stereopsis)
- Suppressed vision in one eye
- Visual fatigue or headaches
- Avoidance of close-up work
- Reduced reading comprehension
Vision Therapy based on monocular exercises (using one eye only) enables each eye to individually develop its visual skills to the greatest possible extent and by combining these with binocular exercises, strengthens the coordination between both eyes and their ability to work three-dimensionally.
- COGNITION. Cognition is the ability to process information based on perception and acquired knowledge. It enables us to interpret, process and create models that represent our reality. Deficient cognition can often result in one or more of the following symptoms:
- Problems following directionss
- Difficulties with reading and mathematics
- Difficulties with space-time
- Difficulties with reasoning and problem solving
- Immature behaviour
- Lack of confidence
- Using compensatory strategies instead of comprehending the concept, etc.
The intention of Vision Therapy is not for patients’ to memorise exercises. The idea is for them to build new models that enable them to develop better at all levels based on the experiences provided by the exercises and their understanding thereof.
- VISUAL THOUGHT. Visual thought is the relationship between movement and vision. Any movement is based on three axes: Horizontal, Vertical and Transversal. The understanding of these 3 axes is going to define the patients’ knowledge of their internal space and this will allow them to become more familiar with the external space and their relationship with it. Poorly structured visual thought can cause the following symptoms:
- Problems copying
- Problems turning
- Problems with reversals
Vision Therapy involves working with games designed to help patients understand the three axes of rotation as applied to their own bodies. We then work on the projection within the turning space on these axes individually before finally working with combinations thereof. This is very important for the development of mathematics.
- MATHEMATICAL THOUGHT. Mathematical thought is the ability to manage numbers and amounts in a logical manner. It is important to have an idea of what numbers are and an image of what they represent instead of being able to recite them from memory without knowing what they mean. Once this has been achieved, numeracy is the ability to read and write numbers, and as this involves every position or location of a number having a value, it is important to know the value of the position instead of memorising it. Once we do, we can really understand a number’s value and work with them. Teachers may well ask themselves why we do this work. The answer is that, in truth, these concepts are visual, that these symbols have to generate an image that we are able to understand by way of visualisation. When there is a lack of sound mathematical thought what we find is low mathematical performance no matter how much time is dedicated to this subject. If we imagine a child who does not have a clear idea of what numbers are, it is hardly surprising that they have difficulties reading them let alone working with them. Vision Therapy works towards enabling patients to have a clear idea of what numbers, fractions, division, multiplication, etc. are so that mathematics is not an exercise in memorisation, but rather can be understood as a concept that the patient is able to visualise.
- VISUAL-MOTOR INTEGRATION. Visual-motor integration is the synchronisation of the eye with the rest of the body. In other words, our vision acts as a guide by providing information to the rest of the body so that our movements can be exact and precise. This is closely related with Binocularity, and it is fundamental in academic skills such as writing, cutting out, colouring in, copying, etc. and ballgame skills: striking (cricket), scoring (basketball), shooting (football), etc. Deficient visual-motor integration can cause the following symptoms:
- Poor handwriting
- Deficient fine psychomotricity
- Sports performance below potential
Vision Therapy manages to improve this skill using the following exercises:
- Gross psychomotricity: with ballgames that involve shooting baskets, batting, etc.
- Fine psychomotricity: improving the patients’ finger skills and, specifically, their prehension grip in any manual activity requiring precision and via eye-hand coordination exercises.
Primitive and Vision Reflexes
At birth the child moves from a highly protected environment into a world full of stimuli in which he or she has to meet his or her own needs. To help them survive children are equipped with a series of primitive reflexes that enable them to respond to the new surroundings facing them. They are necessary for the baby’s survival during the first weeks of life.
If these primitive reflexes are still in evidence between the first 6 to 12 months of the child’s life, they are deemed to be aberrant and are proof of an immature central nervous system (CNS). These non-integrated reflexes are going to affect different areas of functioning: gross and fine motor coordination, sensory perception, cognition and expression. In other words, the main learning bases are going to be affected.
Several of these reflexes are closely related to the development of distinct visual skills such as eye movements, the focusing system, binocular vision and visual perception.
At the same time children are developing their motor skills during the first few months of their lives and integrating their primitive reflexes, they are also developing these visual skills. Children develop their motor, visual-motor and social skills in parallel.
If motor development does not occur as it should, visual skills are going to be affected. For this reason it is important to evaluate and treat the child’s motor development as this is going to constitute an important basis for the treatment of visual problems.
Several primitive reflexes have a direct relationship with different visual skills:
- The Moro Reflex: it is activated by an unexpected and sudden event and is one of the baby’s alarm responses that attract the attention of its caregivers.. If the Moro Reflex has not integrated correctly, visually speaking this might result in Accommodative, Oculomotor and Visual Perception problems. It is also related with photosensitivity and poor pupillary response to light. There might also be vestibular problems, dizziness when moving and poor balance and coordination.
- Asymmetrical Tonic Neck Reflex (ATNR): This reflex involves the baby moving its arms and legs depending on the position of its head. The ATNR enables the first hand-eye coordination and is present when the first fixations on close-up objects appear. Through integration movements, the child trains his/her binocular vision. If this reflex is not integrated, it can be related with poor eye movements and binocular vision problems. This reflex represents a significant impediment to correct Bilateral Integration. Sensory information tends to be processed towards one cerebral hemisphere and difficulties arise with respect to inter-hemispherical crossover and integration, meaning that many children will suffer from reading comprehension difficulties and it is particularly associated with Dyslexia. In addition, there is a connection between the presence of the Asymmetrical Tonic Neck Reflex and the freedom of movement of the joints involved in the child’s grasp and use of the prehension grip so that it is associated with problems of fine hand-eye coordination.
- The Galant Reflex: This reflex plays an active role during the birth process, and when it fails to become integrated it is associated with problems of hyperactivity and attention deficit. Those children who have not integrated this reflex usually find it difficult to sit still in their chairs for any length of time. It is also related with a short attention span and poor short-term memory.
- Labyrinthine Righting Reflex (LRR): The LRR helps the child to adapt to the new gravitational conditions it faces after birth. It exercises an important influence on the muscular tone of the body, which helps the new born baby to begin sitting up. It gives the child the opportunity to practice its balance, develop its muscle tone and work on proprioception. Should this reflex fail to integrate, when the child begins to walk it does not feel secure within the gravitational field because its head movements alter its muscular tone and this varies its centre of balance. It is associated with difficulties in judging space, distance, depth and speed. It is habitually related with problems of balance and the child’s oculomotricity is poor because the ocular-vestibular reflex arch is not functioning well.
- Symmetrical Tonic Neck Reflex (STNR): This reflex helps the baby to overcome the effects of gravity by helping it to lift itself off the floor. It helps to integrate the LRR, and it provides a bridge towards the act of crawling. It divides the body in two horizontally. Visually speaking it trains accommodation because in order to integrate it the child begins looking from far to near, and vice versa, and the distance to which it can see well is extended. If this reflex is not integrated the child does not learn to crawl. It either moves by dragging itself along while seated or it directly stands up and walks. The STNR must be integrated to ensure that the position of the arms and legs does not depend on the position of the head. If the reflex is not integrated, children show poor postures when seated at the table or at school. They read with their faces very close to the book and have poor hand-eye coordination.
- The Palmar Grasp Reflex: This reflex is activated by pressing down lightly on the palm of the baby’s hand and making it close its fingers.
- The Babkin Response: When sucking the child moves its hands. If this reflex is not integrated, problems appear in the motor control of the hands, which manifest themselves in difficulties tying shoe laces, doing up buttons, etc. Children also fail to develop a good prehension grip and this leads to writing problems. They may also make involuntary mouth movements when writing.