Strabismus, also known as "heterotropia", "squint", "crossed eye", "wandering eye", or "wall eyed", is a disorderin which the eyesdo not point in the same direction. It typically involves a lack of coordination between the extraocular muscleswhich prevents bringing the gaze of each eye to the same point in space, preventing proper binocular vision, which may adversely affect depth perception. The cause of strabismus can be a disorder in one or both of the eyes; for example, nearsightedness or farsightedness, making it impossible for the brain to fuse two different images.
When strabismus is congenitalor develops in infancy, it can cause amblyopia, in which the brainignores input from the deviated eye although it is capable of normal sight. Since strabismus can cause amblyopia, which is sometimes referred to as lazy eye, it is sometimes itself inaccurately referred to as lazy eye.
In addition to the visual problem, strabismus can be considered a cosmeticproblem owing to the appearance of the deviated eye.
One study reported that 85% of adult strabismus patients "reported that they had problems with work, schooland sportsbecause of their strabismus".
The same study also reported that 70% said strabismus "had a negative effect on their self-image"
- 1 Types
- 2 Diagnosis
- 3 Treatment and management
- 4 See also
- 5 External links
Strabismus may be concomitant or incomitant.
Concomitant strabismus means that the strabismus is equal regardless of which direction the gaze is targeted.
This indicates that the individual extraocular musclesfunction individually, but that they may simply not be aimed at the same target.
Concomitant strabismus in a child under the age of 6 rarely indicates serious neurologic disorder.
Blindness in one eye usually causes concomitant strabismus, with the eye of a child turning inward, and that of an adult turning outward.
Incomitant strabismus occurs when the degree of misalignment varies with the direction of gaze.
This indicates that one or more of the extraocular muscles may not be functioning normally.
Types of strabismus include:
- esotropia, or one eye turning inward;
- exotropia, or one eye turning outward;
- hypertropia, or one eye turning upward.
- hypotropia, or one eye turning downward.
Medial strabismus manifests as the inability to abduct (move laterally) one's eye. This is usually caused by damage to the abducens nerveor abducens nucleus. The result is that the eye in its normal resting state deviates medially, as the movements of the medial rectus muscleare less opposed by the denervated lateral rectus muscle.
Pseudostrabismusis the false appearance of strabismus. It generally occurs in infants and toddlers whose bridge of their nose is wide and flat. This causes the appearance of strabismus. With age the child's bridge of their nose will narrow and the folds in the corner of the eyes will go away. To detect the difference between pseudostrabismusand strabismus use a flashlight and shine it in the child's eyes. When the child is looking at the light a reflection can be seen on the front surface of the pupil. If the eyes are properly aligned with one another then the reflection will be in the same spot of each eye. If strabismus is present, then the reflection from the light will not be in the same spot of each eye.
If the eye being tested is the strabismic eye, then it will fixate on the object after the "good" eye is covered.
If it is the "good" eye, there will be no change in fixation, as it is already fixated.
Depending on the direction that the strabismic eye deviates, the type of tropia or phoria may be assessed.
Treatment and management
As with other binocular vision disorders, the primary therapeutic goal for those with strabismus is comfortable, single, clear, normal binocular vision at all distances and directions of gaze .
If minor and detected early, strabismus can often be corrected with enforced use of an eyepatchon the dominant eye and/or vision therapy. Advanced strabismus is usually treated with a combination of eyeglassesor prisms, vision therapy, and surgery, depending on the underlying reason for the misalignment. Surgery attempts to align the eyes by shortening, lengthening, or changing the position of one or more of the extraocular eye muscles, and is frequently the only way to achieve cosmetic improvement. Glasses affect the position by changing the person's reaction to focusing. Prisms change the way light, and therefore images, strike the eye, simulating a change in the eye position.
Early treatment of strabismus in infancy can reduce the chance of developing amblyopia and depth perception problems. Eyes that remain misaligned can still develop visual problems. Although not a cure for stabismus, prism lensescan also be used to provide some comfort for sufferers and to prevent double vision from occurring.
In adultswith previously normal alignment, the onset of strabismus usually results in double vision (diplopia).
Advocates of the the Bates methodassert that it can eliminate strabismus , however, this claim is rejected by the vast majority of mainstream eyecare professionals.
- Duane syndrome
- Perfect Sight Without Glasses, chapter 21 and 22.
- All About Strabismus - All Types, All Treatments
- Convergence Insufficiency - Common Condition Confused with Strabismus
- Eye Muscle Surgery for Strabismus - FAQ
- Lazy Eye and Strabismus are Not Same Condition
- Have fun with strabismus
- VisionSimulations.com | What the world looks like to people with various diseases and conditions of the eyecs:Strabismus
Categories: Eye| Ophthalmology
This article is licensed under the GNU Free Documentation License.
It uses material from the http://en.wikipedia.org/wiki/Strabismus Wikipedia article Strabismus.