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Behavioural Optometry and the Australasian College of Behavioural Optometrists (ACBO)i) What is Behavioural Optometry?Behavioural Optometry is an expanded area of optometric practice. A behavioural optometrist has a holistic approach in the treatment of vision and vision information processing problems. A behavioural optometrist believes that your visual status and the way that you interpret what you see does not depend solely on how clear your eyesight is. Consideration must be given to all your visual, visual motor and visual perceptual skills. In this way your behavioural optometrist will not only consider the remediation of any eyesight difficulties but also the benefits of prevention, protection and enhancement of your visual system in order to improve all aspects of your visual performance.
To achieve these goals your Behavioural Optometrist may recommend the use of the following tools:
The Australasian College of Behavioural Optometry (ACBO) was founded in 1987, and provides Australian, New Zealand and Asian optometrists with the opportunity for education and training in the fields of developmental and functional optometry and their application in areas such as learning difficulties, traumatic brain injury, sports vision and binocular vision dysfunction.
A member of ACBO has completed the four or five years of undergraduate study to achieve a Bachelor of Optometry degree. Additional study must to be undertaken in the form of 20 hours continuing education per year in the field of Behavioural Optometry to maintain accreditation. Fellows of ACBO must pass a rigorous assessment program to achieve Fellowship to the College. The evaluation process includes comprehensive written, oral and clinical examinations and the writing of a literature review. Fellows must also undertake 30 hours of additional continuing education each year to maintain their Fellowship accreditation, and must regularly submit papers for publication. Presently aspects of Behavioural Optometry are taught at most Australian universities as part of the undergraduate optometry courses. The University of New South Wales also offers a Behavioural Optometry Course (as a unit of the Master's program). This unit comprises 110 hours of education, and was established in conjunction with ACBO and designed to provide participants with an introduction to the many different aspects of Behavioural optometry. The content provides a neuroscience background together with clinical insights that allow the development of a behavioural model of optometric practice. This course is a prerequisite for Fellowship application to the College.
In 1997 the New South Wales Board of Optometric Registration listed Behavioural Optometry as one of the fields within optometry in which practitioners can achieve specialty recognition. The stringent criteria set out by the NSW Board of Optometric Registration to enable an optometrist to be recognised as a Behavioural Optometry Specialist include post graduate qualifications in optometry as well as achieving Fellowship to ACBO or equivalent. Presently there are a number of Fellows who have achieved this specialty recognition.
Most consultations provided by Behavioural Optometrists, including the initial consultation, attract a Medicare rebate. At the time of examination, your Behavioural Optometrist will be able to advise you of any associated fees and charges that will not be covered by Medicare. Visual DevelopmentThe human visual system is our most dynamic sense. At birth, many of the components of the visual system are in place, such as the eyes, optic nerve and brain, but it is after birth that growth, development, co-ordination and fine tuning of the system occur. The visual system requires light, movement and change in environment to make these developmental processes occur. Vision is generally thought of as what we can see. There are, however, many systems involved before we are able to see things and analyse the information. First we need our eyes to point in the right direction, then the eyes must be focussed and aligned on a target to make it single and clear. The information must then be captured on the retina, processed, and sent to the brain for further processing and assessment. The brain must then make judgements about the information and begin to put actions into place. In this regard, vision is our most important sense, allowing us to move through space, interpret our surroundings and provide feedback over a period of time. (An example is the millions of calculations and recalculations required to accurately catch or hit a ball in sport). It is the normal development of the visual system that allows all the individual systems to coordinate and allows us to function effectively. Behavioural optometrists are particularly interested in the appropriate development of children's visual systems. Of particular concern is how all the component systems operate once the child begins school. A delay in the development of any part of the visual system can have an impact upon the performance of the child at school. This can affect reading performance, concentration and behaviour in the classroom. Regular assessments of your child's vision by a Behavioural optometrist help ensure that all the different parts of the visual system are assessed thoroughly. Some of the changes that occur in the first 6 months of life are: Structure: The newborn eye is remarkably close to its full adult size. At birth the length of the eye is around 17mm, growing to full adult size of 23mm. The power of the cornea is around 50 dioptres at birth, reducing to 43 dioptres as an adult. Vision: The visual acuity of an infant develops rapidly from birth. At 1 month, the child has a visual acuity of 6/180, improving to 6/30 at 2 months and to adult levels of 6/6 (20/20) by 4-6 months. Focusing: Focusing, like visual acuity appears to develop to full adult levels by around 4-6 months. At 1 month the infant has a fixed focus at around 20 cm, which is the perfect distance to see the mother’s face while feeding. At 2 months there is some flexibility, while at 4 months there is adult capacity to vary focus and to fixate on objects at different distances. Visual guidance: At birth, a primitive reflex called the tonic neck reflex exists. This reflex has the head and eyes pointing at the outstretched hand when the head is turned to the side. At 4 months, the child exhibits "swiping" behaviour, where it sees an object and tries to grasp it, but doesn't have the required coordination. At 6 months, the child is able to grasp an object they see. Eye movement: At birth, the child's eyes generally point in the same direction, but they do not work together as a team. This is why it is common for it to appear that there is a turned eye. The eyes generally move together, but only one eye fixates a target. By 8 weeks, the child is generally able to use both eyes as a team.
Vision TherapyVision therapy (also referred to as visual training) is a program aimed at remedying and enhancing an individual’s visual abilities. Its function is to:
Each program of vision therapy must be designed to suit the specific needs of the individual, both in terms of their visual profile and their goals. Diagnostic testing, training procedures and the use of lenses and prisms may be integral components of the successful treatment of a vision problem. The frequency of consultation, the amount of home training and the duration of a course of vision therapy will vary depending on the nature and severity of the problem being treated and the specific needs of the patient. Vision therapy is not used to strengthen eye muscles, but to improve the coordination and efficient functioning and processing of the visual system. Orthoptics is another term often used in conjunction with vision therapy. Orthoptics is one part of a specific vision therapy program directed at improving binocular alignment and visual acuity in individuals with strabismus and amblyopia. Reprinted in part from the Journal of Australasian College of Behavioural Optometrists
Now! Look away now! As it has probably taken a few minutes to get to this page, it is now theoretically time for a 'visual break'. Most eye clinicians agree that extended periods of concentrated close work can contribute to eyestrain. Eyestrain can cause short-term visual difficulties such as transient blur or may contribute to long-term deterioration specifically some types of myopia (short sightedness). Symptoms of eyestrain can include obvious symptoms such as blurred vision, headaches and also loss of concentration. If you find yourself drifting off or staring into space, it may be that your visual system is not efficient. Many computer users report eyestrain symptoms but they consider the ergonomic factors of glare, posture and their monitor size etc before they consider their vision. In some cases spectacle lenses may be appropriate to assist computer users and in some cases vision training is indicated to allow the eyes to work at their peak efficiency. Improvements in how the eyes aim and focus together can lead to greater concentration and increased efficiency for near work.
We all know that a child's development can vary immensely from child to child; it is perhaps not as well known that vision also develops! This also means that vision can be trained or learned through appropriate structured vision therapy. Example: To read left to right partly requires tracking skills but also involves visual-spatial skills. It is important to understand that reading from left to right is actually a culturally and educationally imposed requirement. In many cultures, reading is vertically arranged or in some cases, is arranged from right to left. A child who has not understood or adequately organised the necessary aspects of visual spatial will most likely have difficulty with learning to read. The level of demands on visual skills required for reading increases throughout a child's learning years. Primary visual skills required for early readers are listed below: Tracking and Saccades: Visual Memory: Short Term Visual Memory: Sequencing Visual Discrimination: Focussing Skills: Vision Therapy can assist, overcome or minimise some learning difficulties by reducing visual inefficiencies.
Have you ever heard someone say 'that player has great vision'? Sports commentators often describe a player's ability to accurately judge where other players or the goals are without looking, as 'great vision'. This ability has nothing to do with the player's 'clarity of vision'; it is about peripheral awareness and efficient visual function. Some sports people have these skills naturally, others need to learn to develop them! Vision training activities are a structured series of exercises designed to maximise the efficiency of specific visual skills required for all different types of sports. Examples of how vision therapy can assist your game:
So if your sport involves vision (and let’s face it - most do) then consider a vision examination and talk to your nearest Behavioural Optometrist about your specific sport and its visual requirements.
Eye coordination difficulties may manifest as strabismus (turned eyes). There are many types of strabismus. Some forms are best treated by Vision Therapy used in conjunction with spectacle aids and prisms. Others are best treated by surgical intervention. Strabismus is one of the most complicated visual adaptations that can occur in the human binocular system. It is not always simple to treat and treatment may be lengthy and require a number of different approaches. Typically, vision therapy for such patients will progress through a series of activities such as monocular (using one eye) and bi-ocular (using both eyes) skills and then fusion (putting the images from both eyes together) and binocular (using both eyes together in all directions of gaze) skills. (See also Section 5)
One of the most common complications secondary to a head injury can be visual difficulties. These problems may be related to blurred or double vision but often headaches and eye coordination problems occur. Fortunately, some visual functions recover within a few weeks or months of the injury but often residual problems including a loss in side vision can occur. Vision therapy is an effective tool in regaining control of eye position and eye co-ordination. This combined with the appropriate spectacle prescription can minimise the effect of a field loss. Vision is responsible for providing much of the information we receive. If the quality of visual input has changed due to an injury, vision therapy can be employed with some patients to teach them how to optimise their visual skills. This may enable the individual to be able to access communication devices or to move around more confidently without walking into objects like door frames etc.
Vision and LearningLearning is accomplished through complex and inter-related processes. Your eyes and the visual system grow and develop from the brain, making vision a fundamental factor in thinking and learning. There is currently much concern in the community regarding the level of literacy skills, probably because advances in information technology have increased the demands placed on people to wade through the plethora of written information presented to them each day. As such it is important that the issues regarding vision and learning are well understood by the community, schools and health professionals. In this way optometry can be of help. Not all children with learning problems will have visual difficulties. Likewise, not all children with visual difficulties will be classified as educationally delayed. Even if an optometrist diagnoses an individual with a visually-related learning difficulty, it would not be uncommon for other factors to also contribute to that learning profile. That is, in some instances the visual problems may be primary in the development of the reading or learning difficulty, but more frequently they are contributory. (1) For this reason, optometrists work together with other professional disciplines and believe in a multidisciplinary approach to evaluating an individual’s learning difficulties. Vision can be defined as the mental process of deriving meaning from what is seen. There are three inter-related areas of visual function.
We all know that development can vary immensely from child to child; it is perhaps not as well known that vision also develops! Vision continues to develop after birth and is influenced by the visual environment and the individual’s experience. If a person’s visual system has not developed adequately, visually demanding activities may lead to inefficient or uncomfortable vision. Good visual acuity (clarity of sight) and healthy eyes are no assurance that an individual does not have a vision problem. (See also Section 3 ii) Vision Therapy for Children and Learning Difficulties)
It is axiomatic in the management of learning disabilities that all physical or environmental factors likely to impair the learning process should be treated in the same way as any other aspect of health or development that will make an individual’s learning less than optimal. The purpose of behavioural optometric intervention in the management of children and adults with learning disabilities is to eliminate any vision problem that may obstruct learning. Educational, neuro-psychological and biological research has suggested distinct subtypes of learning difficulties. Current research indicates that some people with reading difficulties have co-existing visual and language processing deficits. For this reason, a vision examination that assesses those factors influencing learning should be included as a crucial part of the multi-disciplinary process. Summary:
Firstly, we should define what we mean by dyslexia and reading difficulties. Dyslexia is a term that means different things to different people. The use of the term dyslexia is easily confused and sometimes used inappropriately to describe anybody who has difficulties understanding left and right, who has difficulties with reversing words and letters, or to describe any degree of reading difficulty regardless of how severe it is. Most experts would agree that true dyslexia relates to about 10% of children who exhibit a learning problem. Their difficulties are usually severe, rare, language based and the cause is obscure. Therefore appropriate professionals must make the diagnosis of dyslexia. Behavioural optometrists do not diagnose or treat dyslexia. The role of behavioural optometric intervention is to identify and treat vision problems that affect all aspects of learning, including reading. Sometimes the signs and symptoms of these vision problems mimic those suffered by people who have dyslexia. It is essential that these vision problems are identified and treated before the final diagnosis of dyslexia is made. Much of the way we learn, both at school and in the workplace, is by reading printed information. While learning itself is accomplished by the interaction of many different processes and skills, processing of visual information (books, newspapers, manuals, e-mail and websites, to name a few) is a major player, indeed the dominant player, in the acquisition of information. Individuals with reading difficulties may experience difficulty in 'learning to read' or may have learned to read but experience difficulty in 'reading to learn'.(2, 3) Perhaps that person lacks concentration or comprehension, or is slow to complete the task, or experiences headaches or sore eyes. Perhaps a child is slower than expected to learn the letters of the alphabet or fatigues easily or has messy handwriting. Perhaps the child is performing satisfactorily academically, yet not as well as expected. All of these cases suggest a vision examination is required. Individuals (both adults and children) with learning problems should receive a comprehensive optometric evaluation. We recommend that children undergo a visual assessment at 6 months of age, at 3.5 years of age and again in the first year of school, the third year of school, the final year of primary school and in the last year or two of high school. This covers the major times in life when the eyes change or when the visual demands on the individual changes. Once school is finished your optometrist will advise when the next assessment is due.
A comprehensive vision evaluation includes an assessment of:
Treatment strategies may include the prescription of spectacles for part time, or sometimes full time wear. Advice may be given on how to adapt the environment and alter work habits to reduce the load on the visual system. Vision therapy may be prescribed to aid visual efficiency and/or visual information processing. (4, 5) Referral to another professional may be an adjunctive or the sole outcome of the optometric evaluation. The expected outcome of optometric intervention is an improvement in visual function with the reduction of associated signs and symptoms. (6) While optometric intervention does not directly treat learning or reading difficulties, it does address physical and developmental barriers to learning, and so renders the affected individual more amenable to educational remediation.(7, 8). The earlier the problem is addressed the better the long term results usually are. References
Developmental and behavioural optometrists use vision therapy as one of many treatments to develop or improve visual abilities. These visual problems include:
Such vision deficiencies are diagnosed as a result of standardised clinical testing procedures. When vision therapy is used as a part of the treatment plan, it is normally carried out in an optometrist's office under close supervision on a regular basis, in conjunction with programmed home therapy. Recently a number of computer programs for vision therapy have become available. These programs offer very useful help for parents carrying out vision therapy at home, in conjunction with an optometrist. However, a computer program for vision therapy cannot provide many of the features of supervised optometric vision therapy, to help a child or adult to achieve more normal visual function and processing to reach their potential. Such computer programs should only be used as part of an overall vision therapy program. They do not work as effectively as necessary if used at home without close professional supervision. Computerised vision therapy programs are not an effective replacement for experienced optometric diagnosis and treatment. Turned and lazy eyes
It is perfectly natural as a parent to feel anxious and a little upset by the fact that your child has a turned eye. One of your concerns will be that your child doesn't look nice with a turned eye. You may have noticed that your child doesn't perform certain visual and eye-hand tasks as well as expected because of the eye turn. You may also be getting lots of so called "helpful" advice from your friends and relatives as to what you should be doing about the turned eye.
The first thing to remember is that the turn doesn't worry your child very much. They are not in any pain or discomfort and as far as they are concerned they can't see what all the fuss is about. This is because when the eye is turned the brain does not pay any attention to it so your child isn't seeing double. Sometimes when a turn is first developing the child will get intermittent times of double vision but the brain learns very quickly to turn one of the pictures off. This is called suppression and if it occurs long enough then the eye that's being turned off won't function as well in terms of eyesight. When the eyesight becomes poor this is called a "lazy eye" (amblyopia) and this will have to be treated before we can get the brain to pay attention to that eye. Lazy eyes are quite common in young children. About 5% of children need treatment for a lazy eye. It's important for you understand that your child's eye turn is not your fault. It's nothing you did to your child that made their eye turn.
There are a number of reasons why an eye may turn. As a result the treatment for each varies. The most common reasons are:
Some children have a combination of both conditions 2. and 3. above. Either way it is important that you understand that rarely is an eye turn due primarily to a muscle problem.
Unfortunately, very rarely will a child grow out of an eye turn. Usually exactly the opposite occurs in that the turn will get worse if left untreated. There may be times when you do notice the turn appears worse depending on how tired the child is, how much close work they have been doing, if they are ill or upset etc. Having said that, even if the eye is turned a little the child will still be making the same adaptations to the problem. That is, the eye will still be turned off and is becoming lazy. Even if your child's eye turns in occasionally or only by a small amount you should have their eyes thoroughly examined. So there are three problems we must address. The first is the eye health. The second is a cosmetic problem of the eye looking unsightly when it is turned. The third is that the eye is becoming lazy. Babies sometimes look like they have a turned eye when actually the bridge of their nose is flat giving the illusion the eye is turned. As the nose becomes more adult-like in shape, the eye no longer looks turned. In these cases, sometimes people think that their child has grown out of having a turned eye, when in fact it was never turned.
The brain of a young child is very adaptable and so can make changes so that they almost see as well as a person with straight eyes. Children with a turned eye have slightly reduced ability to discriminate depth and so tend to be a bit clumsier than other children, however, it does not usually affect their performance at school. We need to remember though that they have a cosmetic problem and only one fully functioning eye.
No. Looking through one eye more than the other does not wear out the good eye.
We have a number of options to treat your child's turned eye. They are:
No single approach is better than the others. The approach depends on what type of eye turn your child has. We may need to use two or even all three to get the best result. If you go back to the most common reason for a turned eye you will appreciate that if we correct the long-sightedness with spectacles we can help straighten the turned eye. The spectacles help remove the reasons why the eye turned. In some cases this is all that has to be done. Another way to think of the role of spectacles in treating the eye turn is to think of them a little like braces on crooked teeth. The braces are added to help straighten the teeth and during this process they are required to be constantly tightened and adjusted as progress is made. In the same way as your child develops the ability to maintain their eyes straight the spectacle lens powers will need to be gradually changed. It is even possible in a minority of cases that the spectacle lenses will be totally eliminated. This depends on a number of factors including the degree of the turn as well as how long-sighted your child is. Don't be worried about not being able to get your child to wear spectacles or how they will look. Invariably your optometrist will be able to show you how to train your child to wear spectacles even from a very young age. No matter how unsightly you think spectacles are, an eye turn is always worse. Besides, the stigma of spectacle wear has long since abated with the colourful and stylish frames that are now available for children. As your child gets older the possibility of wearing contact lenses instead of spectacles is very real. Visual training (or eye exercises) is designed to teach your child to see through the lazy eye and better control their eye alignment. If your child has an eye turn in the first 6 months of life or a true muscle defect then surgery may be recommended. Often only one surgical procedure is required. However, some children may require a second operation. It is uncommon to require a third. If your child needs an operation the surgeon will be able to give you an idea of the chance of having the eye looking straight after one operation. Generally speaking, the goal of surgery is for your child to appear to have “straight” eyes. You may be required to have your child wear a patch or glasses after the surgery. You need to be aware that surgery usually does not treat the underlying problem. But sometimes this problem cannot be found or treated. The eyes may not be perfectly straight after surgery. In some cases we have to settle for a good result rather than a perfect one. Eye muscle surgery is reserved for those cases that are not responding well to glasses. As the results with surgery tend not to be as good as those that can be achieved with glasses (when they work) surgery should not be considered as an alternative to glasses.
As progress is made we will expect your child to demonstrate some variable eye turn behaviour. For example, you may notice sometimes as the eye turn improves the good eye now starts to turn. This does not mean the good eye is deteriorating but rather that the poorer eye is now as good as the good eye. Your child initially may not like their spectacles because they will change their visual world. They may feel strange or things may look funny through them. These symptoms in themselves are not bad and should be viewed as the visual system changing for the better. Either way these symptoms will be short term experiences only. As mentioned earlier as your child improves their spectacle correction may need to be changed. Before treatment commences it is very hard to predict how often this will occur. Sometimes bifocal lenses are also used in the treatment of the eye turn. Children do not have the adaptation problems that adults have getting used to bifocals. Nowadays many different types of bifocals have virtually invisible lines so that often neither an observer nor the child will even know they are bifocals. It will always be important that your child has regular visual examinations throughout their schooling. Optometric CareVision problems and symptoms are among the most common difficulties associated with acquired brain injuries. The nerve systems that control the way the eyes work and focus together, and transmit the visual information to the back of the brain for understanding of our visual world, are the most complex systems of the brain. Vision enables us to be aware of our surroundings and to know where we are in our world, to steer our walking through our environment, to direct hand and other actions to write and hold things, and to help us stay balanced. Since vision systems are in many parts of the brain, it is possible for any insult to the brain to lead to significant effects on a person's ability to read, drive, walk and work. A vision problem can also restrict a person's ability to benefit as much as possible from rehabilitation services. Brain injuries which may cause visual problems can result from:
Injury to the eye or to the brain areas associated with the visual system can result in development of the following:
The symptoms of eye and vision problems associated with acquired brain injury include, but are not limited to, the following:
The signs of such eye problems can include:
The person with vision problems following brain injury should be examined by an optometrist who has special training and experience in care of eye and vision problems related to brain injury. Frequently the optometrist will work together with the occupational therapist, neurologist, general medical practitioner, and other rehabilitative specialists to relate specific visual problems to the effects on the person's ability to function in activities of daily living, as well as the ability to benefit fully from other rehabilitative services. The optometric evaluation of a person with acquired brain injury may include:
Optometric management may include:
Absence of evidence is not evidence of absence. Frequently, acquired brain injuries can cause significant difficulties for people in using vision to walk, work and read, and yet there may not be any medical evidence (such as X-rays, MRI etc) which shows damage to the vision areas of the brain. However, the effects of brain injury on vision can significantly interfere with a person's quality of life, and ability to get better as quickly as possible. The optometrist's role is to provide essential vision services in diagnosing and treating eye and vision problems to maximise the patient's visual function and comfort, and subsequent quality of life. Accommodative Dysfunction
Accommodative dysfunction simply means a focussing problem, particularly at near. This is not so much an eyesight (or clarity) difficulty as a problem in maintaining accurate, comfortable focus particularly with near work.
Focussing problems generally are not muscle problems. Occasionally, a child can fail to establish adequate focussing stamina during their early years of development, but in the vast majority of cases focussing dysfunction problems arise from fatigue as a result of sustained near visual tasks such as reading, writing, computer, etc. So in a sense this problem is an acquired one rather than something being innately wrong with your child's visual system. Prolonged near tasks can be fatiguing to certain individuals. The visual effort required to try to cope with this task can sometimes cause a breakdown in the visual system leading to focussing dysfunction. This can even happen in the adult eye, especially if we are tired, run down or ill, or have commenced a new task with a lot of near work.
The symptoms associated with focussing dysfunction usually occur during or soon after the task in question. The symptoms may include, but are not limited to the following:
Part of the treatment requires the prescribing of spectacle lenses for close work. In many cases this is all that is required. However, for some focussing disorders, visual therapy is also required. Visual therapy on its own does not work well to alleviate these problems. Therapy teaches better control but does not relieve the fatigue component. If vision therapy is required it usually requires a series of in-office visits along with home based therapy between these visits, which are usually one to two weeks apart. Treatment duration will depend on the particular patient's condition. Visual hygiene must also be considered. Regular breaks from near tasks as well as a good working distance (generally elbow-to-fist) from reading or writing material is important.
Generally your child will be required to wear spectacle lenses for at least 12 to 36 months. As this problem occurs due to the stresses placed on the visual system with prolonged near work, the support of spectacle lenses may still be required for exam times, prolonged reading times, reading when tired or ill etc, even beyond the 36 months. Children who have reading glasses do not become dependent on them and do not get worse through the use of spectacles. Ultimately it is expected that most children are weaned out of their glasses. Some children with these problems never improve sufficiently to stop wearing their glasses for reading completely. Your child should have regular reviews throughout their schooling life as the demands of the classroom change throughout the school years. Convergence Insufficiency
Convergence insufficiency is a condition in which the individual has difficulty keeping both eyes turned in to point in the same position when they are doing close work eg. reading, writing, computer work.
The first thing to say is that your child does not have a muscle problem. In other words it is not that your child cannot turn either eye inwards. Rather they are unable to turn both eyes inwards together, and sustain this posture. Occasionally the problem is congenital or occurs very early in life. However, almost always it is a fatigue problem caused by close work in susceptible individuals. One of the reasons for this may be that the child had never refined this ability. With the commencement of school work and learning to read, this problem becomes more apparent. Another reason may be that the visual system may be fatiguing and allowing one eye to drift out. In other words there is a breakdown in the ability to sustain near alignment of the eyes due to visual fatigue.
Individuals who have never refined the ability to maintain their eyes converged generally have very few visual symptoms. These children do tend however, to have poorer fine eye-hand and visual motor skills and will tend to avoid near centred tasks as they have difficulty attending to these. Those children who have acquired the convergence insufficiency problem tend to have more symptoms, particularly when doing prolonged near centred tasks. These symptoms may include, but are not necessarily limited to the following:
The management of the case and the duration of the treatment will depend on why the child has the convergence insufficiency problem. If it is because the child has never refined this ability, then a broader optometric visual therapy program will be required, of which developing convergence skills is but one aspect. In these cases, usually spectacle lenses are not required. Treatment of acquired convergence insufficiency will require the prescription of spectacles. In some cases, because these lenses reduce the visual demands on the visual system this is all that is needed to be done. In other cases however, visual therapy will also be needed to rebuild and develop the visual stamina and convergence skills. It is important that the glasses are worn in the classroom as well as for all homework, reading, computer, or any prolonged close work tasks. In an uncomplicated acquired convergence insufficiency case, visual therapy may take between 4 to 6 in-office visits which are usually spaced one to two weeks apart. For the developmental convergence insufficiency case, a longer period may be required to develop and teach all the required visual skills
Often the reading glasses need to be worn at least 12 to 36 months after the completion of any visual therapy. Usually, by then the child will have developed good stamina and we will then be able to gradually wean them out of their glasses, or reduce wearing time. Periodic follow up should then be provided at least every 12 months during the child's school life since the demands of the classroom increase throughout the school years. Optometric Phototherapy (Syntonics)Optometric Phototherapy, also known as Syntonic Phototherapy, is the use of specific frequencies (colours) of visible light projected into the eyes, to enhance visual efficiency (focus/eye movements) and visual information processing (interpreting what is being seen). Syntonics is defined as ‘balance’, thus Syntonic Phototherapy implies a form of vision therapy being utilised to bring the visual system into balance. Syntonic Phototherapy can be recommended as a stand alone treatment or form one part of a complete vision therapy programme. The treatment involves a complete initial optometric assessment to evaluate an individual’s vision and ocular health status. Following this, if recommended, further assessment to ascertain whether Syntonic Phototherapy may be beneficial is conducted. This involves measuring the visual fields, the area over which one is able to detect light and movement in one’s environment. In Syntonic Phototherapy the visual field is measured using a specialised instrument called a Stereo Campimeter, which allows measurement of ability to perceive not only movement but also different colours. In many cases of visual stress and visually related learning difficulties, an individual’s perceptual visual fields may become temporarily constricted. That is, in cases where there exists an excess of visual information coming into the eyes, more than a person may be able to process in a single eye fixation, then the visual field can reduce in area. This affects the volume of visual information that a person can see and understand with each eye movement, and also affects binocular vision skills. For example, this can affect visual skills required for reading, and in the classroom environment may result in words moving, merging or ghosting on the page and children possibly skipping lines or words as they find it difficult to direct their eyes accurately. In addition, constricted perceptual visual fields can also affect visual-spatial awareness, the ability to perceive and judge where objects are in one’s visual space, an important skill for organising work on the page when writing and also for balance and co-ordination such as in movement and sport. If the Behavioural Optometrist determines that Syntonic Phototherapy may be beneficial for your vision, an individualised programme is designed. The Syntonic Phototherapy involves either in-office and/or home based therapy. For most individuals the therapy would involve hiring a Syntonic Phototherapy unit (otherwise known as a Syntoniser or Syntonics Home Unit) from their Behavioural Optometrist, along with the specific and individually prescribed coloured filters they would require. Common visual conditions where Syntonic Phototherapy may be recommended include:
Myopia (Short-Sightedness)
This medical term describes when a person cannot see distance objects clearly without the need for a corrective minus lens. The traditional view is that light entering the eye from the distance is focussed too early and so the image is blurred. It is also known as near-sightedness or short-sightedness. People with myopia are often those who enjoy reading or using a computer a lot, but this doesn’t necessarily mean that their near vision is better than those who do not have myopia.
In Australia, it is estimated that 20% of adults have myopia and it is generally accepted that the first symptoms of myopia are experienced around puberty. In Asian cultures where children start learning characters at 3 years old, the prevalence of myopia can be as high as 80% of the population. Recent research has suggested careful screening of children at age eight may help identify those children who are at risk of developing myopia. The scientific community also now agrees that myopia is associated with environmental factors that are responsible for its progression. Current research is investigating the interaction of prolonged focussing effort with close tasks, eye lid pressures and poor lighting as aetiological factors in the development of myopia. However the exact mechanism is still not known.
Currently there is no cure for myopia. However, recognising that prolonged near tasks may be a contributing factor for the genesis of myopia, your behavioural optometrist will advise you on proper posture, working distance, lighting and other techniques to help reduce the impact of near visual stress. A lens to make distance viewing clear is the simplest treatment, but is not necessarily the best correction for myopia. It compensates for the distance blur but does not treat any focussing and eye-teaming problems that may also be present and which may be contributing to the myopic progression. Your behavioural optometrist may need to prescribe special spectacle lenses such as enhanced near vision lenses, bifocals or multifocals as a way of clearing the distance blur and at the same time assisting in treating the focusing or eye-teaming problems. Vision therapy may also need to be applied. Other corrective options available are contact lenses, surgery and accelerated orthokeratology. Clinical trials have indicated that wearers of rigid gas permeable lenses and orthokeratology lenses may show a decreased rate of myopia progression but these results are yet to be fully proven by research. Orthokeratology involves using a specially designed contact lens to reshape your cornea while you sleep. Upon waking you remove the lens and enjoy good daytime vision without the need for spectacles or contact lenses. Orthokeratology is reversible and so does not permanently cure your myopia. |
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