6/11/02 News Release

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STANFORD, Calif. — Individuals with extreme nearsightedness, who may not be candidates for LASIK surgery, can be fitted with a new implantable contact lens as part of a phase-III clinical trial being conducted at Stanford University’s Eye Laser Center. The center is one of 15 investigational sites in the United States participating in this trial, and the only site in Northern California

In a procedure similar to cataract surgery, physicians implant the phakic refractive lens behind the iris of the eye. Unlike previously studied implantable lenses that clip onto the front of the eye, the new lens is foldable, allowing surgeons to make a very small incision in the cornea and slip the folded lens into place. The 10- to 20-minute operation requires no sutures.

"This opens up a whole new set of patients we can treat," said Edward Manche, MD, assistant professor of ophthalmology at Stanford University School of Medicine and director of cornea and refractive surgery at the Eye Laser Center.

The implantable lens has a number of potential advantages over other vision correction options, said Manche. The new lens is technically easier to implant than clip-on lenses. It also provides a much better quality of vision than does a laser procedure, which flattens the cornea and alters the eye’s natural optics. And the eye tolerates the lens easily.

"The lenses are made from a material that’s been used in eyes for more than 15 years," Manche said. "Patients don’t feel them, and they won’t wear out or get dirty." Based on European trials, researchers say the majority of patients who receive the implantable lens have 20/40 vision or better after the surgery.

The implantable lens is hydrophobic, meaning it repels water. Once in, it is designed to float over the natural lens of the eye. What remains unclear, however, is whether the lens will stay suspended and not touch the patient’s lens. If this happens, Manche said it may result in the formation of a cataract. To date, this complication has not occurred.

The main concern with implantable contact lenses is the risk of infection, a potentially serious condition that can lead to loss of vision. To limit the risk, Manche performs the surgery, which requires an intra-ocular incision, in a sterile operating room at Stanford Hospital. In the approximately 2,000 patients who have received these lenses in earlier phases of the clinical trials, no patient has experienced an infection, he noted. Other possible side effects include halos and glare, and cloudy or swollen corneas.

Individuals with moderate to extreme nearsightedness, between —8 and —25 diopters on their eyeglass prescription, are needed to participate in the trials at Stanford. Potential candidates can have up to 2.5 diopters of astigmatism. Patients must be between the ages of 18 and 50, and cannot have had previous eye surgeries. The procedure normally costs $3,500 per eye. However, the trial is partially supported by the manufacturer, so the cost is reduced to $500 per eye. The procedure is done on one eye at a time, with a minimum of three months between procedures.

The phakic refractive lens was developed by Medennium and is distributed by CIBA Vision. For more information about implantable contact lenses or to determine if you are a candidate for this procedure, contact the Eye Laser Center at (650) 498-7020, or visit http://med.stanford.edu/school/eye/laser/.

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