Astigmatism is a condition of the eye where light rays are not focused equally on the back (retina) of the eye. It is usually associated with either myopia (nearsightedness) or hyperopia (farsightedness). The eye has two basic components, the optical and the sensory. It is very much like a camera. In a camera there are lenses that focus the light rays onto the film which then converts light energy into chemical energy. Same for the eye except the film is replaced by the retina. The retina sees and stores images and shapes like film does. Nearsightedness is when the optical elements of the eye are too strong and light rays are focused in front of the retina. You can see at near clearly but not far. Farsightedness is the opposite, the optics of the eye are too weak and the eye must use additional focusing power to see clearly. This causes eye fatigue especially when reading.Most people have some amount of astigmatism. It comes either from the front part of the eye, the cornea, not being perfectly round but slightly oval in shape and/or the lens inside the eye being slightly oval as well. You can not see this oval shape with the naked eye as it is very slight. Imagine taking plastic lens out of a pair of glasses and squeezing it until the shape changed, you would be creating an astigmatic condition. The result would be that some of the light rays would elongate and others might shrink.The treatment for astigmatism is either glasses or contacts. If you choose contacts you can go a step further with correcting the astigmatism by using toric lenses. LASIK can also correct astigmatism. Uncorrected, astigmatism can cause eyestrain which may manifest itself in headaches or discomfort while reading or driving. The effects are not harmful nor permanent, just annoying.
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