astigmatism

"What is an astigmatism?" is a question that optometrists hear every day, Astigmatism is the most common vision problem, but most people don't know what it is. It may nearsightedness or farsightedness.

Usually it is caused by an irregularly shaped cornea(called corneal astigmatism). But sometimes it is the result of an irregularly shaped lens, which is located behind the cornea; this is called lenticular astigmatism. Either kind of astigmatism can usually be corrected with eyeglasses, contact lenses or can be by refractive surgery( lasik ).more detail...