Difference Between Strabismus And Amblyopia
Strabismus is a misalignment of the eyes by which they focus improperly on objects and double vision (diplopia) occurs. Cross-eye (esotropia) involves one eye looking at an object and the other turning inward. In walleye (exotropia), the deviated eye turns outward. Children with strabismus usually subconsciously suppress the image arising from the deviating eye; eventually, this eye becomes “lazy.” Temporary treatment consists of placing a patch over the other eye to force the use of the weak eye; glasses, or surgery may eventually be necessary.
Amblyopia, diminished vision in one eye resulting from disuse of that eye during early childhood. Amblyopia is sometimes confused with amaurosis, a partial or total blindness resulting from disease of the optic nerve, retina, or brain.
Amblyopia typically occurs when the vision in one eye is stronger than that in the other owing to a condition such as strabismus (crossed eyes), farsightedness, nearsightedness, astigmatism, or the presence of a cataract. During the first years of life, if the brain’s visual cortex learns to favor the clearer, or dominant, eye, information from the weaker eye will be suppressed, preventing that eye’s normal visual development.
Treatment ordinarily involves (in addition to correcting any underlying disorder, such as strabismus) deterring use of the dominant eye, commonly by covering it with a patch or administering vision-blurring eyedrops. This encourages the weaker eye to compensate for the other and the appropriate neural connections to form. Treatment typically is most successful when performed before a child is seven or eight years old, while the visual system is still maturing. By late childhood amblyopia often is untreatable, although researchers hope to find a means of correcting the condition even into adulthood. A cataract or other visual obstruction present during the first two months following birth—when vision-related centers in the brain are forming—can result in an irreversible condition known as deprivation amblyopia.