Amblyopia ("Lazy Eye")
Amblyopia, commonly known as "lazy eye", is a condition in which vision reduction is not correctable by glasses or contact lenses and is not due to any eye disease. Occurring in one eye, and very rarely in both eyes, it is caused by vision deprivation and/or abnormal interaction between the two eyes. It is estimated that 2-3% of the general population suffers from this form of visual impairment.
- 5 Main Types
Amblyopia caused by a strabismus (eye turn) which did not allow normal interaction between the two eyes. In order to avoid double vision the brain constantly suppresses the deviating eye, thus leaving this eye under-stimulated, which compromises its visual development.
Caused by a difference in refractive error between the right and left eye, even as little as 1.0 D. This difference causes unequal image sizes between the two eyes, resulting in abnormal binocular interaction.
- Stimulus Deprivation
Caused by a lack of visual stimulation because of an opacity in front of the eye(s). Common causes include a cataract, or an eyelid that droops down to obstruct vision for a prolonged period of time.
This condition affects both eyes and is caused by high, but equal, refractive errors (usually hypermetropia).
This type results from vision deprivation in one visual meridian. It can be in one eye or both eyes, and is caused by uncorrected astigmatism.
Treatment of amblyopia begins with treating the underlying cause. Glasses are commonly prescribed to improve focusing or misalignment of the eyes. Eye exercises are also recommended if there is a misalignment, in order to teach better control and "teaming" of the eyes. A final option may include eye muscle surgery to straighten the eyes if non-surgical means are unsuccessful.
Once the underlying cause is treated, the eye doctor may wish to patch the better-seeing eye, to force the "lazy" one to work, thereby strengthening its vision. This can also be accomplished by the use of eye drops that dilate (enlarge) the pupil of the better-seeing eye for the same purpose.