`Breakthrough' lens reduces infections - Health update - contact lens - Brief Article

Do your eyes need air? Absolutely, and that's why old-fashioned contact lenses can leave your corneal surfaces gasping. Happily, a new generation of lenses can improve comfort levels and reduce the possibility of bacterial infection for America's 30 million contact wearers.

The new versions, called the silicone hydrogel lens and the hyper-oxygen transmissible lens (they're easier to wear than to say), were recently approved by the Food and Drug Administration for 30-day continuous wear.

For its ruling, the FDA relied in part on research done at the University of Texas Southwestern Medical Center in Dallas. For a year, the Lone Star scientists compared patients wearing the hyperoxygen transmissible Bausch & Lomb soft lens or Menicon rigid lens with those using conventional lenses. They found that the new soft lenses produced significantly less bacterial binding with no consequential difference between six-night and 30-night wear. They also concluded that hard lenses might be healthier than soft lenses, because the former promote tear exchange, which washes out debris and allows more oxygen to reach the eye.

"For the first time, we have a scientific-based rationale [which] strongly suggests that these new lenses will be the breakthrough in reducing the risk for infection that everyone has been waiting for," says senior author Dwight Cavanagh, M.D., vice chairman of ophthalmology at UT Southwestern.

Conventional lenses disturb the surface of the cornea, according to Cavanagh, allowing pathogenic bacteria to bind to surface cells and potentially initiate infection. Eye doctors have long warned the public against wearing contact lenses overnight, because subsequent eye infections could result in complications such as corneal ulcers, which can lead to permanent vision loss.

"Until now, no apparent clinical progress had been made in ameliorating this critical problem since disposable contacts were first introduced nearly 10 years ago," says Cavanagh.

The study was published in the journal Ophthalmology.