Reviewed by Harry A. Quigley, MD
Glaucoma specialists are on the threshold of monumental changes in therapeutic innovations—from sustained-drug delivery to neuroprotection—that are expected to be available in a relatively short period compared with previous innovations, said Harry A. Quigley, MD.
While lowering of IOP is protective in glaucoma, the current methods by which this is accomplished are wanting because of patient non-adherence to medication regimens.
“We need ways to deliver medications to glaucoma patients that are safe, effective, practical, cost-effective, and have no side effects,” said Dr. Quigley, the A. Edward Maumenee Professor of Ophthalmology and director, Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore.
Sustained delivery seems to be an answer because it minimizes adherence problems, eliminates infection, lowers the dose/side effects with targeted delivery, and provides a broader range of potentially effective medications, he noted.
Medications can be delivered in a sustained fashion in a number of ways: contact lenses, punctal plugs, a tube with reservoir device, intravitreal capsules, and subconjunctival injections—the last of which Dr. Quigley favors.
“Subconjunctival injection is the most secure method that can lower IOP for 6 months and provide documented protection,” he said.
His laboratory is working on administration of dorzolamide injections to lower IOP, which might be combined with a neuroprotector. His group showed that dorzolamide microparticles were neuroprotective in a rat model of glaucoma. One subconjunctival injection of dorzolamide microparticles resulted in half of the ganglion cell loss in the animal model.