August 5, 2009

Contact Lenses May Replace Eye Drops

According to new research, a contact lens that gradually dispenses medication to the eye might ease treatment for glaucoma and other eye ailments, assuming it advances past animal testing to human testing.

People that use eye drops for conditions like glaucoma medicate their eyes several times a day, which is burdensome and inefficient.  Because of the natural blinking of the eye and tear production, only a little bit of medication is absorbed by the eye.  The authors of the study say that the drug-dispensing contact lens may boost confidence and effectiveness.

Dr. Daniel Kohane, director of the Laboratory for Biomaterials and Drug Delivery at Children's Hospital Boston, told Reuters Health that laboratory tests have shown that the drug-dispensing contact lens "can release very large amounts of drug for very long periods of time at a steady rate."

Kohane collaborated with Dr. Joseph Ciolino of Massachusetts Eye and Ear Infirmary, along with other colleagues at the Department of Chemical Engineering at the Massachusetts Institute of Technology, to develop the contact lens.

This is the first time a successful drug-dispensing contact lens has been developed that can give a constant, steady stream of medications at high enough levels to be therapeutic, according to the researchers. 

Kohane said that other drug-dispensing contact lens attempts "have released very small amounts of drugs for long periods of time or a lot of drugs for a short time."

Kohane said that the contact lens his team has developed dispenses the appropriate amounts of ciprofloxacin for 30 days, and, in some tests, even as long as 100 days.  Ciprofloxacin is an antibiotic used in eye drops.

"We're talking really large levels of the drug, for example, enough antibiotic to still be effective for that long," Kohane said.

The lenses are the size and thickness of commercially available contact lenses.  The team said they have begun testing them in animals, and they hope to be testing them in humans soon.

Drug-dispensing contact lenses "could be used with almost any drug that could be applied to the eye, particularly the front of the eye, and for a range of conditions such as glaucoma, allergic conjunctivitis, dry eye, infections, pain, and things like that," Kohane noted.

The researchers noted their findings in the journal Investigative Ophthalmology and Visual Science.


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