Astigmatism
Symptoms and Causes of Astigmatism
Some of the common signs and symptoms of Astigmatism are:
- Eyestrain
- Distorted or blurred vision
- Headaches
Causes of Astigmatism
Human eyes are made out of two parts which focus the images and this includes the lens and the cornea. The normal human eyes have perfectly shaped and smooth curvature and hence the focusing elements perform optimally. The cornea with smooth curvature surface usually bends all incoming lights in the same way and hence it creates sharply focused images on retina. But, when the cornea or the lens are evenly curved the incoming lights are unevenly focused and hence causing refractive errors and Astigmatism is the kind of refractive error.
In the condition of Astigmatism, the cornea or the lens are precipitously curved on one direction than in another and people with distorted shaped cornea usually have corneal Astigmatism. When the lens is distorted you are having lenticular Astigmatism. No matter which type of Astigmatism you are having, but in both the conditions you will experience blurred vision. It may occur more in one direction either diagonally, vertically and horizontally.
Astigmatism may also occur in some patients in combination of some of the other refractive errors like:
- Nearsightedness or Myopia – This is the condition which occurs when the curvature of surface cornea is too long or when the eyes are too longer than usual. Rather than focusing on retina the incoming light focus on front of retina, this leads to blurry vision for distance objects.
- Farsightedness or Hyperopia – This condition is caused when cornea is curving is too small or the eye is shorter than usual. The effects of this condition are reverse to the nearsightedness. Since the eyes are in the relaxed state, the incoming light to eyes focuses behind the eyes and hence making the near objects blurry.
Test and Diagnosis!
Doctors would first review the symptoms and perform a comprehensive eye testing. The testing of your eyes may include:
- Vision testing – Doctors would ask patients to read the letters on chart to test the vision
- Testing to Measure the Curvature of Cornea – Your doctor would use a device known as keratometer which easily measures the curvature of your cornea’s surface and also confirms the presence of Astigmatism and the test is referred keratometry. Doctors may also use a computerized corneal mapping to measure the variations in corneal surface curvature. The test involves usages of keratoscope fitted with video camera to produce the map of your cornea’s surface.
- Test for Measuring Light Focus – In order to learn how your eyes are focusing light, the doctor will place a variety of lenses in front of eyes using a device known as phoropter. Doctors may also use retinoscope to direct a beam of lighting into eyes and this helps in determining how your eyes are focusing light.
These are the test which can help the doctors to know the degree of refractive error and also enables them to calculate the perceptions of the glasses and contact lenses.
Treatment for Astigmatism!
- Corrective Lenses – The doctors may ask you to wear corrective lenses to treat Astigmatism and this helps in counteracting the uneven curvature of the cornea. You may use contact lenses or wear eyeglasses with special lenses to compensate the uneven shape of the eyes.
- Refractive Surgery – Another treatment option is refractive surgery which fixes the issue by reshaping the surface of the eyes. The surgical procedure includes LASEK Surgery and Photorefractive Keratectomy or PRK
These are the two methods to treat Astigmatism in people.