What condition involves a misshapen cornea causing blurry vision?

Astigmatism is a refractive error caused by an irregularly curved cornea, producing blurry or distorted vision.

A typical cornea is nearly spherical, allowing light to focus toward one point on the retina. With astigmatism, the cornea is more oval or egg-shaped, so its curvature differs between directions. Light therefore focuses unevenly, and objects may appear blurred at near and far distances. Astigmatism can also arise from an irregularly shaped lens.

Symptoms may include squinting, eyestrain, headaches, double vision, or difficulty seeing clearly at night. Some people have mild astigmatism with no noticeable symptoms. An eye examination measures the eye's refractive error and determines the correction needed.

Astigmatism is often confused with myopia and hyperopia. Myopia mainly blurs distant objects, while hyperopia usually makes near vision more difficult. Astigmatism can occur alongside either condition and is corrected with glasses, contact lenses, or, in selected cases, surgery.