Astigmatism is a mild imperfection in your eyes that can cause mild vision problems. It can easily be corrected by wearing contact lenses, eyeglasses or through surgery. It occurs due to minor imperfection in the curvature of the eyes. A person having astigmatism will have slightly different curvature in one or both of his eyes. The curvature may not be smooth in all the sides in the cornea. For some people it occurs if the eye is not fully in round shape having slight difference in corners or on one side.
How it occurs?
Eyes are normally round shaped resembling a sphere. On seeing an object, the light enters the eye and by reflection it creates an image of the object in the lens thus giving clear view of the object. But a person with astigmatism the reflection may not be even causing blurry images or wavy images of the object.
Blurred vision, trouble in seeing distant objects, strain on the affect eye/eyes, and headaches are some of the indicators of astigmatism. If you have any of the above symptoms or if your vision is not clear as before or if you have trouble reading/writing then it is time for you to get your eyes tested with the doctor.
Risk Factors :
People who are above 50 years, people with diabetes (for long period), and people with high blood pressure are more prone to develop astigmatism than others. There will be some degree of astigmatism for all the persons who have crossed 40 years.
Astigmatism occurs when the cornea is not evenly shaped leading to refractive error. When there is smooth curvature then the image will be perfectly shaped. But if the surface curvature is not smooth or bent on one side then it produces distortive image. An individual with astigmatism will have cornea that is not smoothly curved causing uneven focus producing refractive error.
Astigmatism can occur along with other errors like myopia and hyperopia. In the case of myopia (nearsightedness) the cornea is curved in excess which causes the light to be focused in front portion of the retina (not exactly on the retina) causing blurry vision. In the case of hyperopia (farsightedness) the cornea is curved very little causing focus on the back of the eyes. In most of the cases astigmatism is present from birth and not caused by watching television (for long periods) or by reading in poor light.
Your ophthalmologist will check for the above symptoms and conduct simple vision test or examine your eyes in special device called keratometer. She will study the nature of curvature of the cornea or the lens thoroughly. Retinoscopy is done to measure the extent of focusing light by the eyes and to assess the degree of refractive error in your eyes.
Depending on the nature of refractive error special eyeglasses or corrective lenses are prescribed. By wearing lenses the improper focus is corrected thereby giving a clear image of the object. Eyeglasses made of special lenses are given for correcting the uneven shape of the cornea. This would also help in correcting the refractive error.
Many people prefer to wear contact lenses in the place of eyeglasses and it comes in wide range of options. You can discuss with your doctor about the benefits of wearing contact lenses. But using lenses for long periods can makes one prone to eye infection.
Refractive surgery is done for reshaping the cornea of the eyes. Lasik surgery is done using a special instrument for making a small round shaped hinge is made in the cornea. The surgeon will gently resize the shape of the cornea in this procedure. Not all the people having astigmatism will have to undergo surgery. Your doctor will try different options for correcting the cornea shape before deciding on refractive surgery.