What is Astigmatism?
Astigmatism is one of the types of refractive errors in which the light rays focus partially on the retina, causing blurred vision. In astigmatism, the curvature is not regular all around the cornea or the lens. In other words, the shape of the cornea or the lens is not normal.
Causes of Astigmatism
The irregular shape of the cornea or the lens is the reason for astigmatism. The following conditions change the shape of the cornea and cause astigmatism.
-Genetic
-Eye infection i.e. corneal ulcer
-Eye injury
-Keratoconus
-Corneal scar
Symptoms
Uncorrected astigmatism can cause blurred vision, distortions, double vision, eye strain and headache.
How is astigmatism diagnosed?
An optometrist or ophthalmologist diagnoses astigmatism during a comprehensive eye exam. They check your eye vision and refractive status to determine the amount of astigmatism and other refractive errors. Your doctor may also do other tests such as refractometry, keratometry, corneal topography etc. to diagnose astigmatism.
How is astigmatism treated?
Prescription
Glasses and contact lenses are the usual methods to treat astigmatism. Lenses that are used to treat astigmatism are cylinder lenses which help bend the light rays onto the retina. Depending on your life style and preference, you can choose glasses or contact lenses. Contact lenses are ideal for sports activities. If you do not like to wear contact lenses or glasses, you may also want to try orthokeratology. Orthokeratology is a procedure in which you wear rigid contact lenses at night to even out the curvature of the cornea. Then you wear contact lenses less frequently. But if you discontinue the procedure, the shape of the cornea returns to the original shape.
Refractive surgery
If you do not want to be dependent on glasses or contact lenses, you may want to pursue LASIK or LASEK or PRK. Refractive surgery is an alternative to glasses or contact lenses.