Repairing vision

North Bethesda resident Glenn Merberg cannot tell the difference between the conventional LASIK surgery he had done in his left eye and the custom LASIK in his right.

LASIK, the common name for Laser-Assisted In-Situ Keratomileusis, is a procedure that uses lasers to repair optical abnormalities in the eye. Custom LASIK uses a wave-front analyzer, a piece of equipment that measures abnormalities in the eye, to generate an individualized or customized map of the eye before the surgical process begins.

Mr. Merberg, 39, was not eligible for custom LASIK in his left eye, which, in February 2004, measured at too high a diaptor, a measurement for a refractive error, for Food & Drug Administration approval. Refractive refers to how the eye bends light in order to see, and refractive error to bending light incorrectly.

“I couldn’t wear my contacts all day. They would be uncomfortable and scratchy,” says Mr. Merberg, who works as a computer consultant. “If I could have worn my contacts, I would have worn them forever.”

Mr. Merberg, who wore contacts for 25 years, waited to have surgery, he says. With surgery, his vision improved to 20-15.

“We now, on a daily basis, can improve people to a level of acuity never experienced in the past,” says Dr. Thomas Clinch, consultant in corneal, cataract and refractive surgery at University Ophthalmic Consultants of Washington, which has offices in Chevy Chase and Northwest.

Custom or wave-front-guided LASIK, approved by the FDA in May 2003, provides better results than conventional LASIK, allowing a higher percentage of patients to leave the operating room with 20-20 vision or better, metro-area ophthalmologists say. The procedure involves taking several measurements of the eye and making individualized surgical corrections. LASIK, performed since 1996, is a type of refractive surgery.

“You end up getting a treatment that is customized to the shape of your cornea,” says John Ciccone, spokesman for the American Society of Cataract and Refractive Surgery, a medical specialty organization based in Fairfax.

Custom LASIK is 25 times more accurate in measuring aberrations, or visual imperfections, in the eye than conventional methods, Mr. Ciccone says.

Ninety-four percent of custom LASIK patients achieve 20-20 vision or better, compared to 68 percent of conventional LASIK patients, according to the FDA.

“Their experience is similar for conventional and custom LASIK, but the results are better for custom,” says Dr. Allan Rutzen, a Fellow of the American College of Surgeons (FACS) and co-director of the University Laser Vision Center at the University of Maryland in Baltimore.

Conventional LASIK measures lower-order aberrations or refractive errors through tests similar to those for fitting eyeglasses and contacts. Lower-order aberrations include myopia or nearsightedness, hyperopia or farsightedness, and astigmatism.

Alternatively, custom LASIK includes higher-order aberrations, suspected of causing visual glare and halos and affecting night vision. Higher-order aberrations, irregularities other than refractive errors, often do not affect vision.

Higher-order aberrations account for 10 percent to 20 percent of visual distortions in the normal eye, says Dr. Robert A. Copeland Jr., chairman of the Department of Ophthalmology at Howard University in Northwest.

“We all have it,” Dr. Copeland says. “We have certain aberrations of the eye.”

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