Modern medicine is all about precision. When you have a cold, you want the virus gone but everything else in your bloodstream untouched. The perfect stitches would leave absolutely no scar behind, and so on.

It turns out that precision is especially difficult when it comes to treating your eyes. For example, you might think that putting in a eye-drop gets right to the problem, but in fact most of it washes off. If the eye drop is medicated, not only does the stuff that washes off miss your eye, it can get in your blood and cause problems of its own. How can we be more precise?

One way has been proposed by researcher Anuj Chauhan and his team at the University of Florida in Gainesville. Chauhan has made a contact lens that delivers medicine to the surface of your eye. The team first made nanoparticles, which are super-small spheres only fifty nanometers wide, of a common drug called Novocain. They added these tiny droplets to a polymer from which you can build contact lenses.

The result? A lens somewhat thicker than normal--but still entirely transparent. And, in water, the new lenses were found to slowly leak the nanoparticles of medicine for eight to ten days. That means if you had them in your eyes, you would be receiving a small, regular dose of your medication directly to the spot where it's needed.

These kinds of drug-dispensing lenses are still in the development stage, but the first steps look promising. It may soon be the case that gentle eye care comes not in a bottle and dropper, but in a lens.