what is an astigmatism

Astigmatism is a common vision problem caused by an error in the shape of the cornea or lens of the eye. Normally, the cornea and lens at the front of the eye have an evenly round shape, which helps focus light rays sharply onto the retina so you can see clearly. With astigmatism, the eye is egg- or oval-shaped like an American football, and light rays do not refract (or bend) properly as they enter the front of the eye, causing vision to be blurry at all distances. Astigmatism can occur at birth or develop later in life, and it may also occur as a result of an injury to the eye or after eye surgery. Astigmatism can be corrected with eyeglasses, contact lenses, or surgery, depending on the severity of the condition and the patients preferences. Symptoms of astigmatism may include blurry vision, needing to squint to see clearly, headaches, eye strain, and trouble seeing at night.