According to the American Optometric Association, an astigmatism is "due either to the irregular shape of the cornea, the clear front cover of the eye or sometimes the curvature of the lens inside the eye." Most people have some level of astigmatism. When an astigmatism is great, it can cause blurred or distorted vision, eye pain and headaches. You can perform a simple test at home to see if you need treatment for an astigmatism.
Wear your contacts or glasses, if you normally wear them, for the test. It is important to have your glasses on if you have other vision problems, such as nearsightedness.
Locate an astigmatism test online. Sit about 14 inches or so away from your computer screen. Make sure you are at eye level and comfortable.
Cover one eye and look at the test with the other eye. Then change eyes. You may have an astigmatism in only one eye. Note any differences.
Look at the lines. You should see distorted or blurry lines if you have an astigmatism. The lines may even appear to be different thicknesses. If you do not have an astigmatism, the lines will be clearly visible and uniform.
Visit your optometrist regularly. Make an appointment if you are unsure of the astigmatism test results. It's a good idea to have your eyes checked at least once a year as your eyes can change as you get older.