what is an astigmatisim? l was wondering if l had it? my eyes change every six months!

Definition:
Astigmatism usually occurs when the front surface of the eye, the cornea, has an irregular curvature. Astigmatism is one of a group of eye conditions known as refractive errors. Refractive errors cause a disturbance in the way that light rays r focused within the eye. Astigmatism often occurs with nearsightedness & farsightedness, conditions also resulting from refractive errors. Astigmatism is not a disease nor does it mean that u have ''bad eyes.'' It simply means that u have a variation or disturbance in the shape of ur cornea.

Astigmatism usually occurs when the front surface of the eye, the cornea, has an irregular curvature. Normally the cornea is smooth & equally curved in all directions & light entering the cornea is focused equally on all planes, or in all directions. In astigmatism, the front surface of the cornea is curved more in one direction than in the other. This abnormality may result in vision that is much like looking into a distorted, wavy mirror. The distortion results because of an inability of the eye to focus light rays to a point.

If the corneal surface has a high degree of variation in its curvature, light refraction may be impaired to the degree that corrective lenses r needed to help focus light rays better. At any time, only a small proportion of the rays r focused & the remainder r not, so that the image formed is always blurred.Usually, astigmatism causes blurred vision at all distances. Some people with very high degrees of astigmatism may have cornea problems such as keratoconus.

Astigmatism is very common. Some experts believe that almost everyone has a degree of astigmatism, often from birth, which may remain the same throughout life. The exact reason for differences in corneal shape remains unknown, but the tendency to develop astigmatism is inherited. For that reason, some people r more prone to develop astigmatism than others.

Symptoms

Distortion or blurring of images at all distances
Headache & fatigue
Squinting & eye discomfort or irritation
The symptoms described above may not necessarily mean that u have astigmatism. However, if u experience one or more of these symptoms, contact ur eye doctor for a complete exam.

Treatment
If the degree of astigmatism is slight & no other problems of refraction, such as nearsightedness or farsightedness, r present, corrective lenses may not be needed. If the degree of astigmatism is great enough to cause eyestrain, headache, or distortion of vision, prescription lenses will be needed for clear & comfortable vision.

The corrective lenses needed when astigmatism is present r called Toric lenses & have an additional power element called a cylinder. They have greater light-bending power in one axis than in others. Your eyecare professional will perform precise tests during ur eye examination to determine the ideal lens prescription. Refractive surgery may be able to correct some forms of astigmatism.

Astigmatism may increase slowly. Regular eye care can help to insure that proper vision is maintained. You may have to adjust to wearing eyeglasses or contact lenses if u do not wear them now. Other than that, astigmatism probably will not significantly affect ur lifestyle at all.

Hope that helps! =]
P.S. I've got astigmatism, believe me u do not want it. My eyes r always tired.

A normal eye has a spherical cornea, whereas an eye with astigmatism is more football shape. Eyes can change with or without an astigmatism at any time. Your eye doctor would know just by looking at your eyes if you have one or not.

see your optometrist to check for sure but you can find heaps of astigmatism tests online, like this one
http://perret-optic.ch/optometrie/test_vision_astigmatisme/opto_test_astigmatisme_gb.htm

basically, if u have astigmatism, instead of seeing say a dot, the dot will look blurred but not symetical like a sphere. eg. it may be distorted horizontally/vertically/at any angle