The university buys the most sophisticated lasers on the market, he said. Patients are screened for risk factors and informed of what they can and cannot expect from LASIK. A surgeon might even do LASIK on one eye at a time.

Those precautions did not prevent Lauranell Burch, a former Duke medical researcher, from suffering serious complications after undergoing LASIK at the Duke Eye Center.

Burch, 47, said that since the surgery March 31, 2004, her eyes sting and burn all the time, eye tissue is wrinkled like a Ruffles potato chip and her night vision is distorted.

"[The damage] is noticeable and on the front of your mind all your waking hours," Burch said. "There's no escape."

In the winter, she takes an anti-anxiety pill about 15 minutes before she drives home in the dark from her job in Research Triangle Park. She compares the distortions she sees at night, also known as star bursts, to explosions of light without a bang.

Burch cut short her follow-up treatment at Duke, became an avid patients' advocate and started to take on LASIK surgeons on Internet Web sites.

Federal privacy laws prohibit Carlson from speaking about an individual patient's case. But the head of the Duke Eye Center acknowledged that LASIK can cause serious complications.

"It's imperfect surgery in an imperfect world," he said.

But Carlson, who did not operate on either Kotsovolos or Burch, estimated that only a handful of the roughly 6,000 LASIK patients he has treated at Duke since 1996 ended up with problems.

The eye center does very well in patient satisfaction surveys, he said.

All LASIK surgeons make an effort to screen patients, and many turn away patients with obvious risk factors.

But LASIK essentially is a buyer-beware procedure.

In choosing a surgeon, patients usually are advised to go with doctors who perform the procedure most frequently. But with LASIK, that advice can be risky.

Dr. Christopher Fleming, an ophthalmologist and former president of the N.C. Society of Eye Physicians and Surgeons, said patients should beware of LASIK surgeons who perform a high volume of operations.

Surgeons who do 10 or 15 LASIK operations a week tend to contract with optometrists who refer patients, Fleming said. In return, the optometrists, who are not medical doctors, screen the patients and do the follow-up care. Some also receive referral fees.

The emphasis on volume, Fleming said, can draw patients into surgery whose eyes are not suited to LASIK. Patients also end up receiving follow-up care from optometrists instead of their surgeons.