Astigmatism

Astigmatism is a vision condition that occurs when the front surface of your eye, the cornea, is slightly irregular in shape. This irregular shape prevents light from focusing properly on the back of your eye, the retina. As a result, your vision may be blurred at all distances.
People with severe astigmatism will usually have blurred or distorted vision, while those with mild astigmatism may experience headaches, eye strain, fatigue or blurred vision at certain distances.

Most people have some degree of astigmatism. A comprehensive optometric examination will include testing to diagnose astigmatism and determine the degree.

Almost all levels of astigmatism can be optically corrected with properly prescribed and fitted eyeglasses and/or contact lenses.

Corneal Modification is also a treatment option for some patients.

Source: American Optometric Association