Researchers design contact lens to administer glaucoma drug

Los Angeles-Researchers at the University of California, Los Angeles, have designed a contact lens that can release controlled amounts of a glaucoma drug, delivering more consistent dosages of the drug than eye drops. 

Bioengineer Dean Ho, PhD, says eye drops often leak out of the eye and arrive in one high-concentrated burst that quickly tapers off, making dosages inconsistent. Ho aimed to make a daily-wear hydrogel contact lens that could release a drug throughout the day to provide a simple solution for glaucoma patients to get the necessary drugs. The lens uses nanodimaonds, faceted carbon particles about 5 nm in diameter, some of which are positively charges, while others are negatively charged. The nanoparticles attract water and can bind and release a variety of molecules.

Ho and the team of researchers at UCLA created a nanodiamond gel. When the gel comes in contact with lysozyme, an enzyme in tears, it breaks down and the drug is released. The gel was used to create a hydrogel lens, and, after some testing, the lens was able to steadily release timolol for 24 hours. After 48 hours, the drug release became less consistent, but researchers say that was not a concern because patients would likely replace the lenses daily.

“While drug-eluting contact lenses are nothing new, the lysozymal process in the gel of the lens is innovative and worth noting. Many of the problems other drug-eluting contact lenses have encountered in the allergy space will be issues with a glaucoma lens as well,” says Ben Gaddie, OD, in Louisville, KY. “Drug-eluting lenses can result in corneal toxicity from the drug or its preservatives, and contact lens-related dry eye and handling problems must be overcome in order for this to be a viable option. Consider having an 85-year-old patient handle a contact lens on a twice daily basis-this technology will have a steep hill to climb.”

Ho plans to test drug-releasing contact lenses in animals and will experiment with adjusting the timing of the drug release to test whether it will have any clinical benefit.