By GRACE HAMMERSTROM
Stanford University's Eye Laser Center is among the first facilities in the country and the only one in California to offer a new customized method to treat patients with debilitating vision loss after refractive laser surgery (PRK or LASIK).
The new treatment helps reshape the cornea to eliminate glare, halos, double vision, night vision problems and other vision loss that may result from complications of refractive surgery.
Conventional laser surgery typically treats the central portion of the eye. If the initial refractive surgery is off center or if the eye heals asymmetrically, patients can suffer impaired vision. The method allows physicians to do offset treatments, which help alleviate some visual disturbances.
The new treatment received federal Food and Drug Administration approval last December under a special "Humanitarian Use Device" exemption, which authorizes the marketing of a device intended to benefit fewer than 4,000 people in the United States per year. Stanford is one of a select group of facilities nationwide to study the procedure in a clinical setting. The procedure is formally known as the Custom Contoured Ablation Pattern treatment, or "Custom-CAP."
"This is really welcome technology," said Edward Manche, MD, assistant professor of ophthalmology at the medical center and director of cornea and
refractive surgery at the Eye Laser Center. "It's exciting because this treatment can potentially help people with no alternatives who are struggling with visual problems."
The procedure links three separate devices: a corneal topography machine, a conventional laser and ablation planning software. The topography machine makes a color map of the eye, pinpointing where to apply treatment and calculating exact specifications for the laser. The ablation planning software then simulates the surgical results on a computer. The surgeon uses the data to precisely control size, depth and location of the laser application, making it possible to reshape the cornea for optimum correction.
Each year, up to 500,000 people undergo refractive laser surgery in the United States. Less than one-half of 1 percent has complications. Of those, about 3,000 patients a year experience an off-center treatment, or asymmetrical healing, which the Custom-CAP is designed to treat.
"We desperately need something to help patients who have had problems," said Manche. "Laser surgery is great, and 95 percent of patients are thrilled. But these patients [who experience complications] haven't had a lot of options."
The new treatment does have some potentially negative side effects, Manche said. It can result in worsened vision, corneal scarring, corneal irregularities or corneal thinning. Moreover, its long-term impacts are not known.
As part of a clinical study, Stanford will follow patients for two years to determine the efficacy and safety of the procedure and whether its effects are permanent. The treatment costs about $3,250 per eye. VISX Inc. is the manufacturer of the technology.
Patients seeking more information about the Custom-CAP can
contact the Eye Laser Center at 498-7020, or visit the center's Web
site at http://www.med.stanford.edu/school/eye/laser/index.html.
Stanford Report, May 22, 2002