Novel glaucoma therapy: One ‘ring’ to help them all?

Glaucoma patients struggling to adhere to a daily eye drop schedule may benefit from a nonsurgical inset that researchers say ensures effective delivery of intraocular pressure (IOP)-lowering drugs.

Published online in the journal Ophthalmology, this study determined a medicated silicone ring worn on the eye could deliver similar IOP-reducing benefits as traditional glaucoma eye drops with little or no patient intervention required.

The double-masked clinical trial included 130 adult open-angle glaucoma or ocular hypertensive patients, half receiving the bimatoprost ring and artificial tears, and half receiving a placebo insert and timolol, with instructions to administer twice-daily drops for 6 months. The study found eye pressure in the timolol group dropped 4.2 to 6.4 mmHG, while the bimatoprost ring group fell 3.2 to 6.4 mmHG with an overall decrease in IOP of about 20%.

Additionally, researchers say the ring was "well-tolerated and safe, with a high retention rate of 89% for both groups at six months." This could be a difference-maker, the study notes, considering patient compliance with daily eye drops can be tenuous at times.

A 2008 study found rates of adherence and persistence with chronic therapies, such as glaucoma treatment, hovered below 50% after only a year, and other studies indicate that factors such as forgetfulness or arthritis limit compliance. But the bimatoprost ring in this clinical trial is designed to be placed and removed by an eye doctor every six months, eliminating the need for regular eye drop usage.

'Future of glaucoma therapy'

A group of eye disorders that triggers progressive increases in IOP to the point of damaging the optic nerve, glaucoma is the second-leading cause of blindness in the U.S., occurring most frequently in people over age 40. Commonly, glaucoma develops with few symptoms, and many people are unaware they have the condition until they experience significant vision loss.

Glaucoma cannot be prevented, nor can vision lost due to glaucoma be restored; however, early diagnosis and consistent treatment can slow or prevent further vision loss. That's why this research proves so interesting, says Murray Fingeret, O.D., chief of optometry at the Department of Veterans Affairs New York Harbor Healthcare System.

"This drug-delivery device and others being developed—punctal plugs, contact lenses—hold great promise in regards to reducing the need to instill eye drops daily," Dr. Fingeret writes in reviewing the research. "Changing the ring every few months may be all that is needed, which would improve drug compliance greatly and probably reduce the burden of glaucoma."

Dr. Fingeret notes the IOP reduction was comparable to timolol—with side effects associated with the active ingredients—and the retention rate was "very good." Additionally, the ring is easy for the patient to see, ensuring the device remains in place.

"While IOP reduction may not be comparable to prostaglandin eye drops, the benefit of not having to instill medications daily may override this factor," he states. "It appears to be comfortable, with this perhaps being the future of glaucoma therapy."

Click here to read about other drug-eluting and novel contact lenses in the July/August 2014 edition of AOA Focus.