FAMILY MEDICINE® COLUMN
By John C. Wolf, D.O.
Associate Professor of Family Medicine®
Ohio University College of Osteopathic Medicine

SURGERY CAN END NEARSIGHTEDNESS, BUT IT'S NOT FOR EVERYONE

Question: I've read a few articles about surgery that can correct nearsightedness, a problem I've had since childhood. The articles talked about a surgery called radial keratotomy. Should I consider this instead of glasses?

Answer: Yes, you should consider all available treatment options for any problem you have, including poor eyesight. I'll try and explain the procedure, radial keratotomy, but I need to start by first talking about the way the eye focuses images.

Most people understand that the eye focuses an image of what is seen onto the retina in the back of the eye much like a camera lens focuses an image onto a camera's film. Most people also know that the lens in the eye adjusts the focus to see objects that range from very close to very far away. What most people don't realize is that the eye has, in effect, two lenses. The clear domed covering over the pupil of the eye called the cornea acts as a lens; in fact, it's really the most powerful lens in the eye. The actual lens, which is located behind the cornea, serves only to fine tune the focus onto the retina.

In nearsighted individuals the combined power of the cornea and lens are capable of focusing on things that are close but they are unable to focus on items farther away. This occurs because the cornea is too domed-shaped. It forms a more powerful "lens" than is needed. The lens of the eye can compensate for this sufficiently to allow close objects to be in sharp focus, but it can't compensate enough to see distant objects clearly. Radial keratotomy is a surgery designed to alter the shape of the cornea to make it into a lens of proper magnifying power.

In radial keratotomy a series of small cuts are made at the edge of the cornea like spokes radiating from the center of a wheel. These cuts weaken the edge of the cornea and allow it to bulge outward at the cuts. The resulting bulging at the edges of the cornea flattens the curve of its entire surface, thereby making it a less powerful lens. The number and location of cuts are specifically designed to bring the individual's vision back to normal. This successfully restores vision to 20/20 in more than 90 percent of these surgeries.

There are other types of surgery designed to improve the vision of nearsighted individuals by reshaping the cornea. Photorefractive keratectomy is one of these. It uses a special type of laser to cut away the center part of the cornea and thereby making it flatter. A third option is keratomileusis, a hard-to-pronounce medical name that describes carving the middle of the cornea into proper shape along with reshaping its edges much like radial keratotomy. Having good vision without having to wear glasses or contact lenses seems like a compelling reason to have one of these surgeries. Unfortunately, about 10 percent of individuals will still need their glasses or contact lenses after surgery. In addition, tiny scars in the cornea can make bright lights at night seem hazy or dazzling. This may be sufficiently severe that some individuals will be unable to drive at night. All of these procedures produce eye pain during healing, and they are also expensive. In addition, all of these procedures work best on those with mild or moderate refractive errors. Those that currently need strong corrective lenses, particularly those with a large degree of astigmatism, are more likely to have unsatisfactory results from these surgeries.

I really can't tell you to have or not to have one of these surgeries. You and your ophthalmologist will need to evaluate the benefits of surgery and weigh them against its potential risks and costs. The final choice is yours.

Family Medicine® is a weekly column. To submit questions, write to John C. Wolf, D.O., Ohio University College of Osteopathic Medicine, Grosvenor Hall, Athens, Ohio 45701.