Common Conditions/Symptoms Associated with Vision


See our page on ADD/ADHD for more information specific to how these conditions relate to vision.

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Amblyopia also know as Lazy Eye is a condition in which one eye sees worse (blurry) than the other despite the best correction with glasses or contact lenses. This means that one eye may be 20/20 while the other eye is not. Because vision in the weaker eye has not properly developed, the brain ignores a significant proportion of the visual information coming from the weaker eye. Since the brain doesn't have the opportunity to use both eyes together, the person with this condition never develops normal 3-D vision.

Amblyopia can occur because of a congenital cataract (cloudiness of the lens inside the eye), unequal refractive conditions (meaning the eyes have a significant difference in glasses prescription that was untreated at a young age), or strabismus (an eye turn that causes one eye to see off to the side while the other looks straight ahead).

Common treatments for amblyopia include patching of the stronger eye, fine visual tasks done with the weaker eye, or vision training/therapy. Because amblyopia is more than just a problem with sight (the 20/20 part of vision), we recommend an active course in therapy to train the brain how to use the two eyes together, because this is something that it has never done before even if the weaker eye improves in sight secondary to patching. Even adults can benefit from treatment of this condition.

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Vision and balance are highly integrated in the brain. The two systems work together to keep you upright and steady. When balance centers in the brain are damaged or underdeveloped, the visual system is most likely affected. On the flip side, when vision is not highly tuned in certain processing loci of the brain, balance and a sense of groundedness can be out of synch. Balance plays a vital role in eye movements and eye movements play an equally important role in how well you feel balanced. Feelings of nausea and vertigo can occur because the two systems are miscommunicating or have stopped talking to each other almost completely. Not all vertigo cases are directly or indirectly linked to vision; however, if vision is ignored the problem may persist despite treatment of the balance system alone. To find out if you have or know someone who you think might have vision problems that relate to balance take our Online Vision Quiz to see if the symptoms match.

Treatment for balance or vertigo problems are centered around reintegrating the visual system and the balance or vestibular system so the two work together in the most efficient way. Vision training/therapy is a good way to accomplish this.

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According to the American Optometric Association (AOA) visual dysfunctions are among the most common aftermath associated with acquired brain injuries. Over 50% of the brain is dedicated to processing vision in some way or another and any injury such as strokes (cerebral vascular accidents-CVA), lack of oxygen to the brain (hypoxia or suffocation), blunt or penetrating trauma can disrupt the intricate balance of the visual pathways. Even a low velocity car accident can cause nerve damage in the brain or brain stem and affect vision.

Those who have significant brain injuries may not realize they have a vision problem at first because of other physical concerns. However, vision should not be overlooked in the rehabilitation process because it has a significant role to play in balance, motor coordination like standing and walking, and fine motor control (all of which are things worked on in rehabilitation).

People with minor brain injuries like those who have whip lash or minor concussions may not even realize that the symptoms they have are related to vision. To see if you have symptoms that relate to vision take our Online Vision Quiz.

Treatment for patients with brain injuries is a collaborative effort that rehabilitation specialists and optometrists can play a part in.

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Double vision results from a misalignment in the two eyes causing the brain to see such different images that it cannot combine the two images in order to see the world as single.

Double vision may come and go from a slight mismatch between the eyes caused by conditions such as convergence insufficiency or convergence excess. Convergence insufficiency is the inability of the eyes to maintain a turned in posture at close-up distances. This condition has many symptoms that are similar to ADD/ADHD and can cause symptoms like words moving around on the page, inability to sustain attention on reading, or fatigue at the end of the day. Convergence excess occurs when the eyes turn in too much when looking up close and can cause symptoms like headaches, eyestrain, or fatigue.

Severe double vision can occur because of strabismus (eye turn); however, if strabismus occurs early in life the brain can eliminate the double vision problem by suppressing the vision from the turned eye causing amblyopia. If strabismus occurs because of a brain injury then double vision is the most likely outcome because the brain has less ability to adapt to the double vision later in life and therefore cannot suppress the second image.

The treatment for double vision can be accomplished with special lenses called prisms, through an active program of vision training/therapy, or a combination of both.

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Dyslexia is often misunderstood as only a problem with letter/word reversals; rather, there are multiple factors in this phenomenon. Dyslexia is also know as "congenital word blindness" as coined by Morgan in 1896. Their are several types of dyslexia, two main ones of which we will cover here-dyseidesia and dysphonesia and a third one we will cover under Letter/Word Reversals.

Dyseidesia is characterized by an inability or a decreased ability to recognize words by sight or sight-words. The brain has limited capability to recognize a word because it is not stored in or accessible from a "vocabulary bank." The child or adult with this type of dyslexia has to rely on the more laborsome task of individually attacking each word phonetically when reading. Decoding phonetically may work for some words, but in the English language there are multitudes of phonetically irregular words.

Dysphonesia is a poor word attack skill. People who have this type of dyslexia may or may not have dyseidesia, but do have a difficult time decoding unknown words by means of phonetics. Even phonetically regular words (ones that sound like they are spelled) are difficult to process for these people. Reading errors can be substitution errors such as home for house and spelling errors are often frequent.

Dyslexia is not always solely a language processing difficulty. In order for the information one reads to travel to the areas of the brain that process language it must first pass through a complex system of visual interpretation. Since vision makes up the first stop on the journey to processing language, it stands to reason that a visual problem can cause a translation error that ends up skewing language analysis.

Treatment for dyslexia depends on the origin of the problem-whether it be language or vision. Sometimes it can be a combination of both. We recommend having a visual evaluation to see if vision is affecting the language center and proceeding from there.

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Eye movements are controlled by 6 small muscles in each eye. These 6 muscles are controlled by 3 different cranial nerves. There are two main types of eye movements, one is called saccades (eye movement jumps) and the other is called pursuits (smooth, tracking eye movements). Saccades are important for reading because the eyes have to jump from word to word and line to line. These are extremely small movements and therefore they have to be extremely precise in order to land the eye on the correct target. If saccades are not working in the most efficient manner possible, the eyes may seem to dart all over the place, words may jump around on the page, or a reader may skip lines. Pursuits are important for following moving targets such as in sports or when watching your hand when writing. When pursuits lack efficiency, eye/hand coordination tasks become difficult if not seemingly impossible.

Treatment for eye movement disorders includes an active course of vision training/therapy.

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If you have two eyes, then eye teaming is a big deal! Eye teaming is the brain's way of combining information from one eye with the information from the other eye to create a solid perception of the world. Since each eye is separated by a certain distance, the right eye sees a slightly different picture than the left eye. So how does the brain deal with these two slightly different pictures? If everything is working together properly, the brain interprets the difference (also know as disparity) between the two eyes as 3-dimensional information and the result is seeing the world in 3-D. If information from the two eyes is not combined because of a visual condition then the brain may see two separate images (double vision) or suppress central vision (the part that allows you to read find print) from one eye causing reduced 3-D vision.

The treatment for eye teaming difficulties is the use of special lenses used to relax the focusing of the eyes or an active course of vision training/therapy.

To read more about the latest research in convergence insufficiency (one type of eye teaming problem) please click this link to view the PDF file of this journal article

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Focusing is an important visual skill for school age children. It allows for them to maintain clear vision up close for extended periods of time (such as in reading). Good focusing also allows them to be able to change focus from the board to their papers and back again. The brain must tell the eyes to change focus rapidly for large shifts in distances (like from board to paper) or it must tell the eyes to maintain an enormous amount of focus for prolonged near tasks like studying. If the brain doesn't understand where to aim the focusing system, visual stress can creep in and cause structural or physiological changes to the visual system. Structural changes occur to the eye by means of elongation of the eyeball in order to reduce the amount of focusing that has to occur at near distances-this change causes distance vision to become blurry and the child becomes nearsighted. Physiological changes can be things like headaches, eye fatigue, or sleepiness at the end of the school day.

Treatment for this type of condition can include special lenses that relax the focusing system or an active program of vision training/therapy that retrains the brain to determine where to aim focusing better. A combination of the two may also be the best means of treatment.

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Letter or word reversals are frequent and common among young children in grade school. Reversals are normal for children up to the age of 8 but should significantly decrease after the 1st grade. Some may be present in second grade, but none should appear in the 3rd grade. Letter and word reversals are a form of dyslexia called dysnemkinesia and are a result of poor motor planning as it relates to language. Children with reversals may also exhibit confusion between their left and their right or left and right on other people. This results from a poor understanding of the body map the brain develops in order to relate to the outside world. The brain maps where the arms and legs are in order to move them accurately through space. The map also contains the left and right labels to further refine those movements through space. A shaky map of the body and left/right awareness can spill over to the language and motor centers that are important for reading and writing.

Treatment for this condition may include a program that reorganizes the brain to have an accurate map of the body and where left and right are located. This can be done through the visual system and vision therapy/training is an excellent way to achieve this.

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According to the American Optometric Association (AOA), 80% of learning is visually acquired. This is extremely important as a child progresses from grade school to high school to college and beyond. Anywhere along the visual pathway, problems can occur to impede the process of learning. Anything from blurry vision (eye) to poor visual processing skills (which occur in higher brain centers) can slow one's ability to learn and/or function in daily life.

In order to avoid the frustrations of learning difficulties related to vision, have your child examined by an optometrist to see if visual skills are capable of standing up to the demands of school work. Check out our Online Vision Quiz to see if your child has symptoms that relate to learning and vision.

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Strabismus is a large misalignment of the eyes usually due to an underlying neurological problem and NOT muscle weakness. Strabismus can occur early in life or later after an event like head trauma or brain injury. Because poor neurological input in the major cause of strabismus, surgery on the muscles is not as effective as rehabilitation of the nerves. Some types of eye turns can be due to structural problems within the eye socket (or orbit). This type of eye misalignment is more likely to benefit from surgery than the majority of strabismus cases.

If strabismus is constant in one eye it can lead to a condition known as amblyopia and have an affect on the clarity of sight. Both conditions need treatment in order to restore the visual system back to a normal or near  normal state. Even adults with this type of condition have been know to be treated with good success.

Treatment for eye turns consists of several options depending on diagnosis. One option is surgery; however, we highly recommend several opinions concerning this method, with at least one opinion coming from an optometrist who specializes in treating eye turns with therapy rather than surgery. The other treatment options for eye turns consist of specialized lenses called prisms to help decrease visual discomfort, lenses to relax the visual system and reduced the eye turn, or an active program of vision therapy/training to retrain the neurology that is the source of the eye turn (in certain cases).

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