Getting drugs into the eye is a tricky business. The eye is well adapted at keeping foreign objects out, so most drugs are washed out by tears, disappear down the eye's drainage system, or simply spilled outside the eye. By some estimates, as little as 1% of any drug delivered to the eye actually ends up inside it.
One potential way round this is to use soft contact lenses steeped in a solution of drug that leach it into the eye. However, it is hard to cram a dose large enough to be clinically significant into lenses, which also tend to leak the drugs away too quickly.
So Mark Byrne, a chemical engineer at Auburn University in Alabama, has a developed a contact-lens material that can hold much greater concentrations of drugs and release them more slowly.
The trick is to design the molecular structure of the lens material to mimic tissue-receptor sites that the drug will target within the body. The goal is to make the dummy receptors strike a balance, not holding the drug too tight, but also only releasing it slowly into the eye.
Byrne has set up a company - OcuMedic - to commercialise the idea and is already developing anti-fungal contact lenses for treating eye infections in horses.
Read the full drug-laced contact lenses patent application.
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