Signs and Symptoms
Astigmatism usually causes vision to be blurry at distance as well as near. Astigmatism usually causes vision to be blurry at a distance and near. In addition, patients with astigmatism often have reading problems proven by a 2016 study conducted by the University of Arizona. The study, published in Optometry and Vision Science, showed children with bilateral astigmatism had issues with oral reading fluency.
Causes
Astigmatism is caused by the cornea having an oblong shape, like a football, instead of a spherical shape, like a basketball.
A cornea with astigmatism has two curves, one flat curve and one that is steep. Light is then focused at two points instead of one. One point of focus may be in front of the retina and the other behind.
This causes images to appear distorted in addition to appearing blurry. Astigmatism may also be caused by an irregularly shaped crystalline lens. This condition is termed lenticular astigmatism.
Diagnosis
Astigmatism is diagnosed by a manual keratometer, an instrument used to measure the curvature of the cornea. A keratometer is often used in a basic eye examination.
The diagnosis also may be made by using a corneal topographer. A corneal topographer is an instrument that gives a color-coded map, similar to a topographical map of mountains. Steeper areas are indicated in red and flatter areas in blue.
A wavefront aberrometer will also give the eye doctor much more precise information about astigmatism.
Treatments
Astigmatism corrects with glasses, contact lenses, or surgery. The American Academy of Opthalmology reports that most people range between 0.5 to 0.75 diopters of astigmatism; however, those measuring 1.5 or more need eyeglasses and contacts.
Glasses: Glasses work well with patients with regular astigmatism to return to 20/20; however, glasses may not do the job if the astigmatism is too high. Contact lenses: Though glasses and soft contacts can correct regular astigmatism, they cannot fix irregular astigmatism; however, customized contacts can work, restoring vision to 20/20. Surgery: Astigmatic Keratotomy (AK) AK, a degree corneal relaxing incision surgery that flattens the cornea’s steep curves that cause astigmatism, is one type of surgical procedure.
LASIK Surgery and Astigmatism
If you have astigmatism, don’t think you can’t have LASIK eye surgery. It is a possibility for most. LASIK surgery is used for correcting refractive errors such as astigmatism, myopia, and hyperopia. Many people with astigmatism have found LASIK eye surgery to be a safe and effective method of vision correction since the U.S. Federal Drug Administration’s first approval of laser device types in 1999. There are more than 30 different FDA-approved lasers for surgery.
Other Surgeries for Astigmatism
While most who have astigmatism can have LASIK, some people have too much astigmatism for the laser to correct. Other corrective surgeries to address astigmatism include photorefractive keratectomy (PRK), radial keratotomy (RK), automated lamellar keratoplasty (ALK), laser thermal keratoplasty (LTK), conductive keratoplasty (CK), or intracorneal ring (Intacs). If you have eye problems, including nearsighted or farsighted issues caused by astigmatism, discuss the following options with your optometrist to determine the best choice for your vision.
