By Dr. Susan Keene
Astigmatism is a distortion or blurring of images at all distances, near as well as far away. Even if you think your vision is normal and are not experiencing blurry vision, the headaches, fatigue, squinting and eye discomfort or irritation you are experiencing may indicate a slight degree of astigmatism. A thorough eye examination including tests of near vision, distant vision and vision clarity, can determine if astigmatism is present.
Astigmatism is not a disease. The exact reason for differences in corneal shape remains unknown, but the tendency to develop astigmatism runs in families. For that reason, some people are more prone to develop astigmatism than others. Having astigmatism simply means that you have a variation in the optics of your eyes and therefore it is correctable. Not all corneas are perfectly curved. Just as many of us need braces to straighten our teeth, so too, many of us have corneas that are not perfectly shaped. The degree of variation of this imperfect shape determines whether or not you will need corrective eyewear. If the corneal surface of your eye has a high degree of variation in the way it is curved, light refraction may be impaired to the degree that corrective lenses are needed to help focus light rays better.
Astigmatism usually occurs when the front surface of the eye, the cornea, has an irregular shape or curvature. Normally the cornea is smooth and equally curved in all directions. Light entering the cornea is focused equally in all directions. In the case of astigmatism, the front surface of the cornea is curved more in one direction than in the other and therefore, the light is focused clearly along one direction, but is blurred along the other so only part of your image is out of focus at any given time.
Astigmatism is diagnosed by a thorough eye examination by an expert. If the degree of astigmatism is mild and you are not diagnosed as nearsighted or farsighted, corrective lenses may not be needed. If your degree of astigmatism is great enough to cause eyestrain, fatigue or headaches, prescription lenses will be needed for clear and comfortable vision.
Of interest to parents, astigmatism may contribute to poor schoolwork but is often not detected during routine eye exams at schools. If your child is complaining of headaches or difficulty in concentrating, difficulty in reading for any length of time, please have his eyes examined and share these symptoms with your eye doctor.
Astigmatism is a very correctable disorder both with eye glasses and contact lenses. Make an appointment with our office to ensure your vision is the best it can be and don’t let astigmatism derail your day.