Astigmatic Keratotomy

What is astigmatic keratotomy?

Astigmatic keratotomy (AK) is a procedure in which an eye surgeon makes cuts in the cornea to reduce astigmatism. The cornea is the clear outer layer on the front of the eye. If you have significant astigmatism, your vision is somewhat blurry all the time.

How does it work?

Astigmatism occurs when the cornea is curved unevenly. Often there is more curvature in one direction than in the other. With astigmatism, light rays that normally focus in one point on the retina (light-sensitive tissue at the back of the eye) have no single point of focus. This causes images to appear blurry and distorted.

During AK the surgeon usually makes two cuts in the cornea. The cuts allow the cornea to flatten and become more evenly rounded. Then light rays focus more normally inside the eye, so your vision is clearer.

When is it used?

AK is usually an elective procedure. This means that it is not urgent and sometimes not essential. AK may correct your astigmatism. With successful AK, you may not need glasses or contact lenses, or you may be able to have thinner lenses in your glasses.

To determine whether you can benefit from AK, see your eye doctor. After examining your eyes, your doctor will tell you if AK might be helpful for you. Procedures that use a laser to reshape the cornea, such as PRK or LASIK, may be preferable.

How do I prepare for the procedure?

Do not wear contact lenses for several weeks before your first exam. On the day of the surgery, do not wear any makeup.

You will need to arrange for someone to take you home after the surgery. Allow for time to rest at home.

What happens during the procedure?

You may be given a sedative to help you relax. Then your eye doctor will put special eyedrops in your eye to numb it. Some surgeons may use a marking pen to mark the eye in the examining room before making the cuts in the cornea.

While you are lying under the microscope, your doctor will make tiny, arc-shaped cuts in your cornea using special instruments. No cuts are made in the center, which is the part you see through. The length, depth, and placement of these cuts depend on how much your cornea needs to be reshaped.

AK usually takes less than 30 minutes. You will feel little or no discomfort during the procedure. Usually your doctor will treat one eye at a time. Some people need more than one AK.

What happens after the procedure?

You will be in the recovery area for about an hour after surgery or until you are ready to go home. You may want to rest at home for the rest of the day.

You will be able to resume most of your normal activities soon after the procedure. Wear your old glasses or safety glasses to protect your eye from injury. Do not rub your eye.

You may feel some discomfort. Your eye will probably feel gritty for a few days. It may look red and be more sensitive to light than usual. Your doctor will give you eyedrops and may prescribe pain medicine. The drops will help the cornea heal and will help prevent eye infections.

Usually the cornea heals slowly. Your vision may continue to change for weeks or months after the procedure. Some people still need to wear glasses or contact lenses. Most people need reading glasses for close work after about age 40.

What are the risks of this procedure?

Like any medical procedure, AK may have side effects. Side effects of AK may include:

• temporary pain
• vision that varies from time to time
• seeing halos around lights
• difficulty in fitting contact lenses.

Complications may include:

• return of your astigmatism after a while
• scarring of your cornea
• cataract
• eyelid problems
• dry eye
• eye infections
• loss of vision (rare).

Talk to your doctor about these and other possible side effects and complications and their treatment.

What are the benefits of this procedure?

After successful AK, your vision will be less blurry. You may be less dependent on glasses or contact lenses.

When should I call my doctor?

Call right away if you have:

• severe or worsening pain
• loss of vision
• a lot of drainage from your eye.

Overall, AK is a relatively safe and effective procedure. Many people are satisfied with their vision after AK. Be sure to talk with your doctor about any questions or concerns you have.