Corneal Irregularities and Astigmatism

Donnie Rhett Koonce is an ophthalmic assistant who practices with Charlotte Eye Ear Nose & Throat Associates, PA, and performs optical screenings. Through his position, Donnie Rhett Koonce has gained insight into a wide range of eye conditions, including astigmatism, which involves an irregularity in the cornea’s curvature.

The cornea is a clear covering on the outer part of the eye that has a primary function of bending, or refracting, light. This serves to focus the light that enters the eye and passes through the pupil and past the iris to the retina. Not containing blood vessels, which would cloud vision, the cornea is supplied with nutrients through aqueous humor and tears produced by the anterior chamber of the eye.

Astigmatism occurs when the cornea has more curvature in one direction than another, which is typically due to genetic variation, in the same way that people may have differently shaped feet. In relatively few cases, corneal scars, keratoconus (a rare condition when the cornea becomes irregularly shaped), or swollen eyelids may cause the astigmatism. In general, corrective lenses are enough to correct the blurred vision caused by astigmatism.