The eye condition glaucoma, which afflicts some 67 million people and is second only to cataracts as the world's leading cause of blindness, is often treated with eye drops that relieve the unusually high pressure inside the eye.
Contact lenses with vitamin E, however, just might deliver more medication to treat glaucoma almost 100 times longer than current lenses, says Anuj Chauhan, a chemical engineering professor at the University of Florida in Gainesville who helmed the research team investigating this new treatment:
"The problem is within about 2 to 5 minutes of putting drops in the eye, tears carry the drug away and it doesn't reach the targeted tissue," said Chauhan. "Much of the medicine gets absorbed into the bloodstream, which carries it throughout the body where it could cause side effects. Only about 1 to 5 percent of drugs in eye drops actually reach the cornea of the eye," Chauhan explained.
The team's new, medicated contact lenses are loaded with vitamin E, which is proving to be far more successful at keeping the glaucoma medicine near the eye, the research team announced at a meeting of the American Chemical Society in San Francisco this week.
The tiny aggregates of vitamin E molecules form what the researchers call "transport barriers," thereby slowing the transfer of medication from the contact lens to the eye. This extended-release delivery causes the drug to have eye contact for far longer than the 2-5 minutes typical with the more standard eye drop method.
"These vitamin structures are like 'nanobricks,'" Chauhan said in the news release. "The drug molecules can't go through the vitamin E--they must go around it. Because the nanobricks are so much bigger than the drug molecules--we believe about a few hundred times bigger--the molecules get diverted and must travel a longer path. This increases the duration of the drug release from the lenses."
In the team's animal testing, the drug was administered up to 100 times longer than is typical with current commercial lenses. Chauhan says the lenses might be able to be worn nonstop for up to a month, and could even treat cataracts and dry eyes.
The team expects to initiate human clinical trials in the next year or two.