Astigmatism

Optical defect in which refractive power is not uniform in all directions (meridians).

Light rays entering the eye are bent unequally by different meridians, which prevents formation of a sharp image focus on the retina.

See What are myopia, hyperopia, astigmatism, and presyopia?

See other terms from Glossary of Eye Terminology.

betsy – October 8, 2006 – 10:58