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Contacts you can wear for a month

New materials create lenses that can 'breathe' better than any so far, experts say.

October 28, 2002|Valerie Reitman | Times Staff Writer

A new generation of recently approved contact lenses offer such a dramatic improvement in comfort, convenience and safety that some people are forgoing the popular laser eye surgery to correct their vision.

Thanks to significant breakthroughs in lens materials, consumers can now safely wear contacts around-the-clock for up to 30 days, without the hassle of taking the lenses out at night, cleaning them and putting them back in the morning. And the new lenses have been shown to be safer to wear for extended periods than competing types of lenses worn for less time, according to several eye doctors who have tested them in clinical trials.

"It's like the difference between DVDs and videos," said Dr. Dwight Cavanagh, vice chairman of ophthalmology at the University of Texas Southwestern Medical Center in Dallas. "Once you've seen a DVD, you don't buy any more videos."

The new products are CIBA Vision's Focus Night & Day soft lenses and Menicon Co.'s Menicon Z rigid gas permeable lenses. The Food and Drug Administration approved the products for 30-day wear in the United States during the past year, but the new lenses have been slow to catch on with consumers and doctors. Many eye doctors are not yet familiar with the products, and some believe that existing contacts are safe enough.

But eye-care professionals say they expect public awareness to grow.

Some eye doctors recommend the lenses as an alternative for consumers who are considering Lasik eye surgery, a popular vision-correction technique used to treat nearsightedness. Although many Americans have had Lasik surgery, some people have been reluctant to undergo the costly procedure because of concern about possible complications. The procedure carries a very low risk of serious complications, such as blindness, but a somewhat higher rate of less severe complications, such as dry eyes or glare. Many people are wary of taking any risk when it comes to their eyesight.

The new lenses allow at least double -- and in many cases, six to eight times -- as much oxygen to nourish the cornea as the various brands now on the market. Inadequate oxygen for the eyes is believed to have been a chief cause of earlier problems with continuous-wear lenses that led to sight-threatening infections and corneal ulcerations. After approving some contacts for 30-day "continuous wear" in the 1970s, the FDA in 1989 set tighter restrictions on the lenses, allowing a maximum "extended wear" time of just seven days.

The new lenses, which sell for between $200 and $500, including fittings, are made of plastics that allow the eyes to breathe "just like lungs do," says Mary Jo Stiegemeier, a Beachwood, Ohio, optometrist who participated in the FDA trials of Menicon Z lenses. She was initially apprehensive about allowing her patients to sleep with their lenses on for weeks on end. After a month of continuous wear, however, their corneas looked "like they'd never worn a contact lens"--a significant improvement from the aftermath of wearing other kinds of lenses for less time, she said.

The new lenses also significantly minimize the adherence of bacteria. The lens surface is more natural and "bio harmonious with the molecules of the body, which is extremely important, said Joseph Barr, a professor of optometry at Ohio State University and editor of Contact Lens Spectrum, a medical journal. "The patients and the practitioners, and I don't mean to demean them, really don't comprehend the significance of this technological breakthrough," he says. "In the past 20 years , we've been trying to make lenses like this--with all that oxygen--that are comfortable, wettable and bio-compatible."

The two lenses are made from different materials and function differently. Menicon's lens, which is thin and bendable but still considered "rigid," is a copolymer of the materials siloxanylstyrene and fluoro-methacrylate, touted as strong yet porous. To demonstrate to visiting doctors how much oxygen it allows to reach the eye, Menicon covered a fish tank with its polymer material. The fish, which need oxygen to survive, continued to swim without problem, meaning enough air was passing through the polymer to allow them to breathe.

CIBA Vision's soft, rubbery Focus Night & Day lens are made of silicone hydrogel. The FDA also approved a similar soft lens made by Bausch & Lomb, but CIBA Vision, sued for patent infringement, successfully blocking Bausch from selling its "Pure Vision" lenses in the U.S. However, Baush is appealing the decision and continues to market them internationally. Still, convincing consumers that the new lenses are safe to wear for a month may be an uphill battle, considering the bad publicity that the first generation of continuous-wear lenses received in the 1980s, when some patients suffered severe corneal infections.

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