A contact lens designed to deliver medication gradually to the eye may improve outcomes for patients who struggle with imprecise, difficult to self-administer eye drops. (John Earle Photography)
People suffering from glaucoma who find eye drops painful or inconvenient may one day have another option at their disposal: contact lenses that dispense their medication more precisely.
Monday in the journal Ophthalmology, researchers at Harvard University detailed promising results of the device, which dispenses the common glaucoma treatment latanoprost, in four monkeys.
Study authors argued the lenses could improve the estimated 50 percent adherence rate of eye drop use for glaucoma. Although there is no cure for the eye disease, which is the leading cause of irreversible vision loss in the United States, eye drops can help relieve pressure in the eye to help prevent progression. Researchers compared the lenses’ ability to relieve this pressure using a dosage equal to eye drops as well as to that of a higher dose.
"We found that a lower-dose contact lens delivered the same amount of pressure reduction as the latanoprost drops, and a higher-dose lens, interestingly enough, had better pressure reduction than the drops in our small study," first author Dr. Joseph B. Ciolino, an ophthalmologist at Massachusetts Eye and Ear and an assistant professor of ophthalmology at Harvard Medical School, said in a news release. "Based on our preliminary data, the lenses have not only the potential to improve compliance for patients, but also the potential of providing better pressure reduction than the drops."
Unlike previous similar contact lenses that dispensed latanoprost too quickly, the new device dispenses the drug in a more controlled manner, researchers said. In a 2014 study, Ciolino’s team showed their lens could deliver medication continuously for one month, according to the release.
The lens is comprised of a thin film of drug-encapsulated polymers in the periphery. The film slows distribution of the drug, and its placement on the periphery allows clearance of the lens’s center to avoid impacting vision or moisture levels in the eye.
According to the news release, the lens can be designed to be refractive or not, with the ability to correct near- or far-sighted eyes.
Next, study authors plan to study the lenses in humans and to further confirm their findings in the higher-dose lens.
"If we can address the problem of compliance, we may help patients adhere to the therapy necessary to maintain vision in diseases like glaucoma, saving millions from preventable blindness," Ciolino said in the release. "This study also raises the possibility that we may have an option for glaucoma that's more effective than what we have today."