Astigmatism is a condition that affects the shape of your eye, and almost all of us have it to some degree. Thankfully, astigmatism can be easily corrected through eye glasses, contacts or surgery. A common refractive surgery to correct astigmatism — and other refractive errors — is LASIK. Approximately 700,000 people undergo LASIK (laser-assisted in situ keratomileusis) annually.
If the clear front part of your eye — known as the cornea — is shaped like a perfectly round ball, which is the ideal, light comes into it and is bent evenly thus providing a clear view. If your cornea is shaped more like a football, the light gets bent more in one direction than another meaning only part of an object is in focus, so things at a distance may appear blurry or wavy.
Symptoms of astigmatism, which come on slowly, include: blurred or distorted vision, eyestrain, trouble seeing at night, and even headaches. It's common to have astigmatism along with other refractive errors including farsightedness (hyperopia) and nearsightedness (myopia).
Refractive errors are the most common eye problems in the United States. Approximately 11 million Americans 12 years old and up could improve their vision through a refractive procedure, according to the National Eye Institute.
"LASIK corrects astigmatism in the same way it corrects near or farsightedness — by creating a flap, and then removing ultra-thin layers from the cornea to reshape it," says Dr. Yuna Rapoport, a board-certified ophthalmologist. "The laser is pre-programmed with specific measurements for your eye, and astigmatism is one of the measurements that is programmed."
During this procedure, a surgeon uses an instrument called a microkeratome or a femtosecond laser to cut into cornea in the front of the eye, which has five layers. A flap, which is created by cutting into the first two layers, is peeled back in order to reshape the tissue underneath with another laser. After that's done, the flap is put back in place. The procedure takes approximately 20 minutes, and approximately 96% of patients will achieve their desired vision.
"By being able to adjust the curvature of the cornea very precisely, the doctor is able to remove the astigmatism or the football shape from the cornea," says Dr. James Thirion, an optometrist. "The flap is then flipped back over and smoothed to allow crisp clear vision instantly."