Strabismus comes from the Greek strabismos meaning twisted, and results from a lack of parallelism of the visual axes of the eyes. Often, the cause of strabismus is not known, but it appears to be hereditary and is usually obvious soon after birth. Cosmetically, strabismus causes a squint—convergence or divergence of one or both eyes from the parallel line. Sometimes the term "cross-eyed" is used to describe one or both eyes turning toward the nose, and "wall-eyed" when one or both eyes turn outward. It may be concomitant (nonparalytic), in which the divergence or convergence remains the same no matter what way the eyes turn; or noncomitant (paralytic), which means the deviation is more noticeable when the eyes look in one direction than in another. Strabismus is often correctable if treated before the age of four or five years.
- Vision Disorders - Nonparalytic Strabismus
- Vision Disorders - Other Refractive Errors
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