What is Astigmatism?
Astigmatism is a condition of the human eye which causes either blurred vision or a sense that each eye is seeing objects slightly differently. It is not a vision problem, but a structural problem of the eye. The human eye is usually shaped like a soccer- or tennisball, but with astigmatism, the cornea of the eye is curved instead into an oval shape, more like a rugbyball. When the eye is not curved properly, or has uneven curves like a rugbyball, light will not travel in and out of the eye normally. Astigmatism causes light to bounce unevenly off the flat and steep curves of the oval shaped eye, thus allowing light to focus to more than one point in the eye. This causes the blurred vision.
How is Astigmatism detected ?
There are several ophthalmological tests to determine the presence and level of astigmatism. A keratometer and a corneal topographer measure the curvature of the cornea. An autorefractor can give an estimate of the eye's ability to focus light properly. Most ophthalmologists and optometrists are able to detect even slight degrees of astigmatism with just a simple eye exam.
How can Astigmatism be treated ?
Glasses or contact lenses can be prescribed to treat astigmatism, but they generally do not correct the condition. Often, two different lenses will help the eyes focus together, thus offsetting the uneven focusing caused by astigmatism. Astigmatism, however, can be corrected with surgery. Lasik and astigmatic keratotomy are two commonly used surgeries for astigmatism. The object of surgery is to reshape the cornea of the eye and make it more spherical.
Astigmatism is quite common, with thirty percent of the population having some level of cornea curvature. Often, mild astigmatism goes largely unnoticed, but severe astigmatism may cause, in addition to blurred vision, headaches, squinting and fatigue. Most people with astigmatism are born with it, but the awareness of it increases with age.