March 14, 2001

Thousands of nearsighted Americans are thinking about undergoing LASIK this year. Why? Because for the first time there is a safe, reliable vision correction procedure that offers a quick recovery.

INTELIHEALTH FEATURE-

By Sara Gambrill

Thousands of nearsighted Americans just like Judy are thinking about undergoing LASIK this year. Why? Because for the first time there is a safe, reliable vision correction procedure that offers a quick recovery. This procedure can free nearsighted people from having to wear glasses and contact lenses for distance vision.

What Does LASIK Do?
LASIK changes the shape of the cornea to mimic the shape of the lens — a concave lens in the case of a nearsighted person — used in a pair of eyeglasses or contact lenses. Lasers are used to change the shape of the eye, more specifically the cornea, allowing the eye to see with near-perfect or perfect vision. (Most patients walk out with somewhere between 20/20 and 20/40 vision.)

The laser treatment allows the cornea to bend, or refract, light coming toward the eye and lens, so that it comes into focus on the retina at the back of the eye. A nearsighted, or myopic, eye is too long, so an object will always come into focus in front of the retina, instead of on it, requiring the person to get closer to the object to see it. LASIK can compensate for this by adjusting the length of the eye.

Penney K. Miller, 46, had LASIK done on both eyes with great results. Miller says there's only one reason she wanted to get the procedure done: convenience.

"I have to travel a lot for my job, and I hated packing up my contacts and the solution for trips. I also hated getting up in the middle of the night and not being able to see," she says.

What Happens During Surgery?
Miller describes the experience of undergoing LASIK, "I had not worn my contact lenses for a few weeks before surgery, as I was told, because contact lenses affect the shape of your cornea. When I arrived for surgery, I was given a sedative and then I was asked to change out of my street clothes and into a special suit that covered me from head to toe. In the operating room, the surgeon put anesthetic drops in my eye and kept my eyelids from shutting with a special instrument, which didn't hurt at all."

During LASIK, the surgeon uses a keratome, a mechanical knife, to slice across the cornea and make a flap that is hinged back to expose a layer of stroma, the middle layer of corneal tissue. A laser vaporizes the amount of tissue needed to give the cornea the correct curve relative to the length of the eye.

"All I could see was the light of the laser," Miller says. "You really don't see anything but that. I could hear some popping sounds too." Then the corneal flap is returned to its original position. "After having the procedure done on both of my eyes, the doctor escorted me back to the waiting room and asked me if I could read the clock on the wall. "Yes! I can!" I said. I was so excited. I could see so much better right away."

After The Surgery
After the procedure, the patient must wear special protective goggles at night for about a week. It is advisable to go home and rest with the goggles on for a few hours after the procedure. There is a checkup both a day after and a week after. Most people, like Miller, feel no pain during or after the procedure, and they walk out with the vision they want.

Some patients do not get the vision they want with the first procedure and may choose to undergo LASIK a second time. Almost all patients get the vision they want with the second procedure.

LASIK is not without risks, which can include infection, difficulty seeing at night and what is called interface haze (hazy vision at the point where the flap was cut). Blindness is also a risk, as it is with any type of eye surgery. In addition, vision can be overcorrected with LASIK. The risk for these side effects, however, is very low. "LASIK is a safe, reliable procedure," says Don C. Bienfang, M.D., director of neuro-ophthalmology at Brigham and Women's Hospital and assistant professor of ophthalmology at Harvard Medical School. "That doesn't mean everybody should rush right out and get it. Not everybody is a good candidate for various reasons."

Who Gets The Surgery?
Should you undergo LASIK? It depends. First of all, LASIK costs around a few thousand dollars per eye and is not covered by insurance.

The real issue with LASIK is that you should not undergo the procedure if your prescription is changing and is not stable. This is common in the teens and early 20s. People in this age group probably should not undergo the procedure because their eyes may have not stopped changing. "The teens and 20s are a dynamic time for your eyes," says Dr. Bienfang. If you are nearsighted, you can become more so during this stage of life. If you were to undergo LASIK at age 22, for instance, you might have to undergo it again at age 24 because your eye's ability to bend, or refract, light may have changed. However, people aged in the teens in 20s who have a stable prescription are good candidates for LASIK.

The following people, however, should not undergo LASIK:

• People with very thin corneas — These people simply do not have enough corneal tissue for the surgeon to work with.
• Candidates for cataract surgery — During cataract surgery, patients are given an artificial lens, which should also correct for nearsightedness.
• People with diabetes — The epithelium, or outermost layer of the cornea, is thin in diabetes patients.
• People with rheumatoid arthritis or lupus — These patients can have problems with dry eyes, and LASIK can cause some dryness.

Another consideration is presbyopia. Presbyopia is a natural process that the eye goes through, typically around age 40. It is when the lens of the eye begins to lose its ability to focus. The lens becomes more rigid and, as a result, less able to change its shape according to whether it's focusing on an object that is near or far. LASIK can change the shape of the cornea, but it cannot stop the lens from becoming more rigid, so people who undergo LASIK before they experience presbyopia will still need to wear reading glasses after about age 40. People older than 40 who wear reading glasses will still have to wear them after undergoing LASIK.

LASIK patients in their 30s who have a relatively weak prescription, such as two diopters, are making a tradeoff. For 10 or 15 years, they can have perfect vision because of LASIK, but when presbyopia sets in, they will need reading glasses. If they do not undergo LASIK, they will not need reading glasses when they are older, but they will still need a light pair of glasses for everyday activities. "Some of my happiest patients are the 50- and 60-year-olds who are two-diopter myopes," says Dr. Bienfang.

LASIK can be a real life-changing experience. Miller says, "I'm very satisfied with the results. I don't have to travel with a lot of extra stuff just so I can see. Swimming is wonderful now. And I don't have to find my glasses in the middle of the night just to see." When asked what her life is like now, Miller responded, "Amazing!"

What is a Diopter?

Prescriptions are written out in the number of diopters. one diopter equals a lens that takes rays of light and brings them into focus at one meter. a two-diopter lens brings rays of light into focus at half a meter, and a three-diopter lens, at a third of a meter. each whole diopter increase reduces the distance at which the lens can bring an object into focus.

Related Reading:

Ask the Doc: Eyes/Vision
Nearsightedness
Farsightedness
Presbyopia
Eye Disorders

Used with permission of the copyright owner. All rights reserved. This article is not intended to provide advice on personal medical matters or to substitute for consultation with a physician.