Astigmatism
Astigmatism Causes
The cornea and the lens are the parts of the eye responsible for image focusing. In a normal eye, both parts have perfectly smooth curvature resembling a smooth ball. The cornea or lens refracts or bends incoming light and produces a sharply focused image on the retina or the back of the eye. But if distorted, light rays will not be properly refracted. This refractive error in astigmatism is caused by the cornea or lens being more steeply curved in one direction than the other. In most cases, affected patients are born with astigmatism at birth. In some cases, however, the condition develops following an eye injury, surgery, or related diseases.
Astigmatism Definition
Astigmatism is characterized by a mild defect in the curvature of the eye which causes blurry vision. Astigmatism is an easily treatable condition. In astigmatic patients, the cornea or the lens of one eye has a slightly different curvature in one direction from the other. It comes in two forms: corneal astigmatism, characterized by a distorted cornea; and lenticular astigmatism, characterized by a distorted lens.
Astigmatism Diagnosis
Astigmatism may be determined with the following diagnostic tools: a keratometer, a keratoscope, and a videokeratoscope. These devices measure and evaluate how light is reflected from the corneal surface or lens.
Astigmatism Symptoms and Signs
Astigmatism has the following distinguishing symptoms: blurry vision; visual field distortions; eyestrain or fatigue; headaches; plus a blurring of diagonal, horizontal, or vertical lines.
Astigmatism Treatment
In treating astigmatism, the goal is to even out the distorted curvature that's causing vision problems. Most cases involve prescribing corrective lenses and/or recommending refractive surgery to correct the distorted cornea or lens. Some refractive surgical procedures available today include: Laser-assisted in-situ keratomileusis or LASIC surgery; PRK or photorefractive keratectomy; and Laser-assisted subepithelial keratomileusis or LASEK.