New Contact Lenses Deliver Medication to the Eye

New technology may replace eye drops currently used by people suffering from glaucoma and dry-eye.

Studies have found that a majority of glaucoma patients regularly skip their eye drops, putting themselves at risk for blindness, and that even when drops are used regularly, only a small percentage of the medication tends to be absorbed into the eye.

In an article published in the July issue of Investigative Ophthalmology and Visual Science, scientists announced that they have developed a contact lens that delivers medication to the eye at a constant rate for over 4 weeks. The lenses should not affect the wearer’s vision.

The special lenses were created by dissolving a biodegradable polymer called PLGA in an organic solvent, to which medication was added. After the solvent evaporated, researchers coated the polymer film/medication mix with a hydrogel called pHEMA — the same material used to make regular contact lenses. Researchers believe they can vary the molecular weight of the polymer to change the rate of drug release as needed.

To date the researchers have only tested the diffusion properties of the lens in a lab dish, but expect to be able to test the lenses in humans within a year.

SOURCE: A Drug-Eluting Contact Lens, Ciolino, et al, Investigative Ophthalmology and Visual Science. 2009;50:3346-3352.)