Lenses for everyone: New materials make contacts safer, comfier

 
 
Published: 10/22/2007 6:21 AM

Contact lenses have come a long way since 1887, when German physiologist Adolf Eugen Fick fashioned two 20-millimeter thick slabs from brown glass, doused them with a sugary solution, and plopped them onto his eyes.

While Fick's unwieldy lenses hurt so much he could only bear them for a few hours, today's contact lenses are more comfortable and safer than even 10 years ago and offer new options for people with conditions like presbyopia, the loss of near vision that happens in middle age.

"The technology out there now is really mind boggling," says Thomas Steinemann, an ophthalmologist at MetroHealth Medical Center in Cleveland, Ohio, and a spokesman for the American Academy of Ophthalmology. With so many choices, finding the right lens can be confusing. Here's a rundown of what's out there and what works best.

Silicone hydrogels: Contacts can be a pain; about 67 percent of the more than 36 million Americans who wear contacts say the lenses irritate their eyes. "About a quarter to a third of contact users drop out," says Russell Worrall, an optometrist and an assistant clinical professor at the University of California-Berkeley.

In 1998, Bausch and Lomb unveiled the first silicone hydrogel lenses, an improved version of the soft lens introduced in 1971. Silicone hydrogels allow up to six times more oxygen to reach the eye, on par with the most current gas-permeable rigid lenses. That's important, because lack of oxygen can lead to corneal swelling and infection.

"With silicone hydrogel you're getting a lens that breathes better and doesn't dehydrate as much, so it's healthier for some patients," says Jack Schaeffer, an optometrist in Birmingham, Alabama, and chairman of the American Optometric Association's contact lens and cornea section.

In the first half of 2006, use of silicone hydrogel lenses increased 50 percent, in part because they are the only lenses the U.S. Food and Drug Administration approved for 30-day wear. Despite this, many doctors remain wary of infection risks with extended wear, because they know patients don't always clean and replace lenses as recommended.

"If a patient is noncompliant -- say, they're going to try to wear them for two months -- we will not sell them extended-wear contacts," says Schaeffer, noting that his practice doesn't allow children to wear them.

Toric lenses: About one quarter of people have astigmatism, in which the surface of the eye is irregularly shaped. Toric lenses that correct for astigmatism came out in 1978, but the ballast that kept them positioned also made them thicker and less comfortable. Recent design refinements have improved the situation considerably.

"If you are someone who gave up on toric contacts even five or 10 years ago because of discomfort or poor vision, now is a good time to try them again," says Richard Weisbarth, the vice president of North America Professional Services for CIBA Vision, a lens manufacturer, and president of the American Academy of Optometry.

Bifocals and multifocals: By the time most people reach their mid-40s, they develop presbyopia, or "short-arm syndrome." The eye's lens becomes less elastic and can no longer focus for reading or close-vision tasks.

Until recently, the treatment of choice for contacts wearers has been monovision, in which one lens corrects for distance vision and another for near vision. But monovision takes some getting used to -- the brain has to learn when to use information from a particular eye. New configurations for bifocal and multifocal lenses, including aspheric designs with blended near and far zones, and concentric "bull's-eye" designs are luring people from monovision.

In a recent study, 68 percent of successful monovision lens wearers preferred multifocals when they tried them. Nathalie Maio, 57, a lawyer from Franklin Lakes, New Jersey, who has myopia, presbyopia and astigmatism, wears soft multifocals.

"I think they're great," she says. "My friends are always struggling to find their glasses, but I can always read the menu."