Convergence insufficiency is the most common eye muscle disorder among children and adults. When we read or look at anything close, the eyes have to cross (or converge) slightly in towards the nose to allow single vision. Convergence insufficiency results from difficulty maintaining the eyes in this crossed posture. When convergence is reduced, the individual must exert excessive effort to maintain single vision. This typically causes headaches, eye strain, burred vision and double vision during sustained reading or close work.
Eye Teaming, Focusing and Tracking
Eye teaming, or binocular vision, is a visual efficiency skill that allows both eyes to work together in a precise and coordinated way. Focusing allows maintenance of clear vision during reading and computer work and immediate clarity when changing focus from one distance to another. Eye tracking allows accurate following of moving objects and moving the eyes from word to word during reading. Problems in these areas cause double vision, headaches, blurred vision, eyestrain, and loss of place especially during reading and close work.
Concussion and Brain Injury
50% of the brain’s neurons are involved with the visual system in some way. Thus, a wide range of visual problems can result from concussion and brain injury. Due to the complexity of the brain networks that control vision, even mild concussions can often cause problems.Vision therapy can be very effective in restoring normal visual function after concussion or brain injury.
Visual Processing Issues
Visual processing, or visual perception, is the brain’s ability to analyze and interpret visual information. Visual processing is important in letter and number recognition, early reading and math skills, handwriting, and the ability to copy and organize written work. In some children, the development of visual processing skills does not keep pace with their growth in other areas. This lag of development can lead to difficulty acquiring a sound foundation in reading, handwriting, and math skills in the early grades.
Amblyopia or Lazy Eye
Amblyopia is reduced vision that is not correctable with glasses. It results from a crossed eye or drifting-eye condition called strabismus or by unequal optical prescriptions in the two eyes. Amblyopia occurs when the brain is unable to “fuse” or combine the information coming from both eyes, and gradually shuts off one eye. Fortunately, however, amblyopia can be treated effectively at almost any age.
Strabismus refers to a condition where both eyes do not point in the same direction. Larger amounts of strabismus can be noticed just by looking at someone’s eyes. Smaller amounts are only detectable with special tests. Strabismus can be present at all times or intermittently, meaning the eye turns only some of the time. Strabismus is often hereditary, and is usually first noticed from birth to age 5. When children develop strabismus, their brain learns to suppress one eye to prevent double vision. This will reduce depth perception, can cause amblyopia, and can affect balance and gross motor skills even in very young children.
Vision and ADHD
The signs of ADD/ADHD and vision problems overlap. Children with vision problems can show poor attention with classroom work and homework. Teachers and parents will often notice children taking frequent breaks, avoiding reading or becoming fidgety as their eyes fatigue.Vision issues such as farsightedness, eye teaming problems, and focusing problems can affect a child’s ability to sustain attention during reading and desk work. Research has shown that children with convergence insufficiency are more likely to have a diagnosis of ADHD.
Vision and Dyslexia
Dyslexia is a frequently overused term, and is often mistakenly thought of as reading or writing letters backwards. But the main problem with dyslexia is usually persistent difficulty with phonics – the ability to attach sounds to letters and blend the sounds into words. Vision problems can also make reading more difficult, causing problems with fluency, speed and comprehension. But vision problems do not cause dyslexia. Vision therapy is not intended to treat dyslexia. Children with reading problems need a thorough vision evaluation to determine whether there are any vision problems affecting their reading. We do not diagnose dyslexia or language based reading disability, but we perform screening tests of phonics and decoding when indicated, and will refer to educational specialists if these are a concern.