Astigmatism

Astigmatism occurs when the front surface of the eye, the cornea, has irregular curvatures. Normally the cornea is smooth and equally curved in all directions. Thus, light enters the eye through the cornea is focused equally in all directions. With astigmatism, the front surface of the cornea is curved more in one direction than in the other. This abnormality results in vision that is distorted, as if looking at a wavy mirror.

Astigmatism is one of a group of eye conditions known as refractive errors. Refractive errors cause a disturbance in the way that light rays are focused within the eye. Astigmatism often occurs in combination with other refractive errors, nearsightedness and farsightedness, or myopia and hyperopia.

Usually, astigmatism causes blurred vision at all distances. Some people with very high degrees of astigmatism may have cornea problems such as keratoconus.

Treatment

Astigmatism can usually be corrected with eyeglasses, contact lenses or refractive surgery.