Contacts could dispense drugs. (Drug Delivery).

Eye medication usually comes in drops. That's not good, says Anuj Chauhan. Only about 5 percent of the medicine treats the eye. The rest drains into the body, where it can reach the bloodstream and cause complications. Better, Chauhan says, would be a more controlled way of getting medicines into the eye.

That's why he and his coworkers at the University of Florida in Gainesville have created contact lens materials designed to continuously dispense drugs. To make sample lenses, the researchers first prepared 50-nanometer-wide spheres containing the anesthetic lidocaine. They added these nanoparticles to a common contact lens polymer called poly-2-hydroxyethyl methacrylate.

The team made test lenses that were a little bigger and thicker than normal contacts. Despite the nanoparticles, the lenses retained their transparency. When placed in a beaker of water, the lenses leached their loads of anesthetic for 8 to 10 days.

The researchers now plan to test their particles with timolol, a glaucoma drug usually delivered in eye drops, and the antibiotic ciprofloxacin. They also hope to tune the lens material so it releases drug molecules uniformly over time. If all goes well, drug-releasing contacts may be on the market in about a decade, Chauhan says.--J.G.