Laser procedures to correct vision are becoming increasingly popular, but not everyone is a good candidate for such treatments.

When you’re looking for a surgeon, cost shouldn’t be your bottom line. Look for a surgeon with experience who does a careful patient evaluation.

Laser eye surgery has become the latest trend for the nearsighted who wish to join the ranks of the clearsighted. It’s quick, virtually painless and probably available at a mall close to you.

In 2000, an estimated 1.5 million Americans underwent laser eye surgery and that number will probably increase this year. Anyone considering laser eye surgery should be aware that not everyone is a good candidate for the procedure, complications can and do occur and the skill and experience of your eye surgeon is an important consideration.

LASIK (laser in-situ keratomileusis) is the most commonly performed laser eye surgery for vision correction today. It’s most often used to treat nearsightedness, an excessive curvature of the cornea. The laser flattens the cornea, improving vision and allowing many people to get rid of the thick lenses they have worn since childhood.

In the LASIK procedure, often referred to as “flap and zap,” the surgeon uses a computer-operated scalpel called a microkeratome to lift up a flap of the epithelial layer that covers the cornea. The laser is then used to zap the cornea, vaporizing a prescribed amount of tissue to flatten it slightly. The excimer laser doesn’t burn, rather it breaks the molecular bonds of cells in the cornea.

The laser itself takes only a few seconds to zap the cells. The flap is then put back in place and doesn’t require any stitches. The whole procedure takes only about 15 minutes. Anesthetic drops in the eye make the surgery painless.

The eye is covered for a number of hours. When the cover is removed, the improvement in vision is usually remarkable. A person who couldn’t make out a face across the room can now read a notice on the wall.

Studies of LASIK show that between 90 and 95 percent of qualified patients can expect uncorrected vision equal to 20/40 or better after their surgery.

Patients need to remember that visual correction with glasses or contacts is 20/20, so although they can see far better than before the surgery without glasses or contacts, their new vision without glasses will not be quite as sharp when viewing distant objects. Patients typically describe the effect as soft focus.

Visual acuity of 20/40 without glasses is the standard required for a driver’s licence. Individuals can use glasses after surgery when precise distance vision is required, at a ball game or the theater, for example.

Don’t Overlook Complications
As with any surgery, LASIK bears a risk of complications. Serious complications are rare, but some studies show that about 5 percent of patients will have some type of complication.

A relatively frequent complication is under or over-correction. A patient who formerly needed glasses for distance vision may need them after surgery for close-up work.

In some cases additional surgery can be done as “enhancements” to sharpen a patient’s vision. Studies show that uncorrectable vision problems and persistent dry eyes occur in about two percent of cases. Careful patient screening prior to surgery can eliminate some of these risks, however, if unqualified patients are not accepted.

Infection, displaced flaps, blur, fog and flare are all potential complications. Infection after the surgery is a relatively rare but potentially serious complication because it can cause scarring that interferes with vision.

A number of patients report reduced night vision after LASIK. Halos around lights at night can also be a problem and may interfere with night driving. Ophthalmologists warn those whose work depends on night vision to be cautious about surgery.

An irregular astigmatism can sometimes occur usually due to poor flap positioning after the surgery or to poor healing. Damage or distortion of the flap may lead to a permanent decrease in best-corrected vision.

Patients who are over age 45 and nearsighted will almost certainly need reading glasses after the surgery. Younger people aren’t affected in the same way because their eye muscles are more flexible.

Monovision correction is an option for these older patients. One eye is corrected for near vision, the other for distance vision and the brain learns to accommodate the two sets of information. Some patients find this a good solution, others are never able to adjust and need to have both eyes corrected to match.

If you’re considering this option, it’s possible to have a trial run by asking your ophthalmologist to make up a pair of glasses with comparable corrections.

Cost is a major concern for anyone considering laser vision correction. It’s not normally covered by medical insurance and the surgery typically costs from $1750 to $2500 per eye.

When you’re looking for a surgeon, cost shouldn’t be your bottom line, however. Look for a surgeon with experience, at least 100 LASIK procedures, who does a careful patient evaluation. Costs should include pre-and post-surgical evaluations, medications and revisions if they are needed.

Other Options
PRK (photo refractive keratotomy) is a simpler procedure than LASIK because it requires no cutting. The laser strikes the surface of the cornea, carving away a specified amount of tissue.

Because the flap is not used to expose the cornea in PRK the epithelial tissue needs to regrow after the procedure. Vision takes about a week to clear up, and recovery can be painful. Full recovery takes from three to six months.

PRK is more likely than LASIK to cause problems with haze after the procedure, butbecause there’s no cutting involved, there’s no risk of complications related to poor positioning of the flap or of irregular healing. PRK does however carry a risk of scarring because tissue must be regrown over the cornea.

A new procedure, LTK (laser thermal keratoplasty), uses a laser to shrink and steepen the front of the eye for better retinal focus. As with PRK, there’s no cutting involved.

The Food and Drug Administration approved LTK in mid-2000 initially as a temporary treatment. Studies showing that its benefits may extend for 10 years have caused the FDA to remove the temporary label.

LTK is usually used to correct for farsightedness, but it does offer some benefit for nearsightedness as well. Patients must be at least 40 years old and should understand that even with LTK they may still need reading glasses. Experts say that vision will regress in some patients after the procedure. In other words, the eyes may spontaneously return to less than perfect vision over time.

Laser eye surgery is changing the way we think about vision correction, allowing many who woke every day to a blurry world to throw away their glasses and contacts and to greet the day with naked eyes. But laser eye surgery comes with subtle tradeoffs such as less than 20/20 vision, a risk of complications for a small percentage of patients and considerable cost.

If you’re thinking about laser eye surgery make sure you’re an ideal candidate, be informed about realistic expectations and possible complications and choose your surgeon with care.

REFERENCES:
Paul M. Dowd and Jeffrey M. Augustine, “The Optical Aberrations of LASIK, Review of Optometry, February 15, 2000.
“Eyes Wide Open About LASIK,” Harvard Health Lettter, October, 1999.
“First the Flap, Then the Zap,” Harvard Health Letter, October, 1999.
“Is Laser Surgery To Correct Vision Right For You?” Tufts University Health and Nutrition Letter, November, 2000
Paul Karpecki, “What’s New in Refractive Surgery.” Review of Optometry, .May 15, 2000
Carol Lewis, “Laser Eye Surgery: Is It Worth Looking Into?” FDA Consumer, July-August, 1998.
Mary B. Marcus, “Before You Get Lasered, Squint at the Fine Print,” U.S. News and World Report, March 27, 2000.
“One in 20 LASIK Patients Will Develop Complications: Are You Prepared to Manage Them?” Review of Optometry, August 15, 2000.
Theresa Wilson, “LASIK Surgery,” AORN Journal, May, 2000.