Amblyopia, also called "lazy eye," is an eye condition which develops in early childhood when nerve pathways between the brain and eye are not properly stimulated. If left untreated, the brain learns to see only blurry images with the amblyopic eye, even with glasses in place.
Amblyopia symptoms may include:
- Squinting or closing one eye to see things
- Poor depth perception and contrast perception
- Poor visual acuity in general
Amblyopia is often difficult to diagnose in children, since they often don’t know they have a vision problem. A doctor usually tests for the condition by blocking each eye and observing the patient’s response to visual tests. Amblyopic patients will often tend to do poorly on three-dimensional image tests.
Several conditions lead to Amblyopia:
- Strabismus (crossed eye) — A condition where the eyes are misaligned, and do not gaze at exactly the same target. A child’s brain will adapt, and learn to ignore the image from the crooked eye, to prevent double vision. Surgery may be necessary to treat the strabismus, but the weak eye must also be treated for amblyopia.
- Refractive discrepancy — In this case the eyes have markedly different levels of nearsightedness, farsightedness or astigmatism. The blurrier eye is ignored by the brain. Once diagnosed, this vision condition may be treated with corrective lenses; however, often the amblyopia must be treated as well.
- Eye clouding or obstruction — Other eye problems such as trauma, congenital cataract, scarring, or anything preventing a clear image can result in disuse of that eye. The ophthalmologist must address the obstruction, often by surgery, and then treat the amblyopia.
Treating amblyopia requires therapy aimed at making the child use the weak eye, most commonly achieved by using an eye patch over the dominant eye for a prescribed amount of time, until the weaker eye matches the stronger one. Alternately, the ophthalmologist may prescribe a lens to blur the vision in the dominant eye, or recommend daily use of atropine eye drops in the dominant eye to prevent it from focusing These serve the similar purpose of imposing use of the weak eye.
Proper treatment during early childhood often lessens or reverses amblyopia; however, it is common for the disorder to recur during this period, requiring treatment to resume. Once a child passes the age of nine, amblyopia will usually not relapse if it has been successfully treated. Conversely, it is much more difficult to treat older patients with amblyopia although treatment may still be worthwhile for those beyond early childhood.