A novel explanation of glaucoma is rapidly rising, and it is promoting advances in treatment that may ultimately eliminate the disease. Rather than being viewed solely as an eye disease, top scientists now consider glaucoma to be a neurologic disorder that causes nerve cell death, similar to what happens in Parkinson’s disease and Alzheimer’s.
Treatment advances are being tested in patients or are scheduled to begin clinical trials soon.
The long-standing theory regarding glaucoma was that vision damage was caused by unusually high pressure inside the eye, known as intraocular pressure (IOP). Therefore, lowering IOP was the focus of surgical techniques and medications; developing tests and instruments to measure and track IOP was vital to that effort.
Although measuring a patient’s IOP is still a key part of glaucoma treatment, it is no longer the only method an ophthalmologist uses to diagnose glaucoma. Even when surgery or medication successfully lowers IOP, some glaucoma patients continue to lose vision.
Also, some patients find it difficult to use eye drop medications as prescribed by their physicians. These problems encouraged researchers to look beyond IOP as a cause of glaucoma and focus of treatment.
The new research model focuses on the damage that occurs in a type of nerve cell called retinal ganglion cells (RGCs), which connect the eye to the brain through the optic nerve and are vital to vision.
RGC-targeted glaucoma treatments now in clinical trials include: medications injected into the eye that deliver survival and growth factors to RGCs; medications known to be useful for stroke and Alzheimer’s, such as cytidine-5-diphosphocholine; and electrical stimulation of RGCs, delivered through tiny electrodes implanted in contact lenses or other external devices. Human trials of stem cell therapies are in the planning stages.
“As researchers turn their attention to the mechanisms that cause retinal ganglion cells to degenerate and die, they are discovering ways to protect, enhance and even regenerate these vital cells,” said Jeffrey L Goldberg, M.D., Ph.D., assistant professor of ophthalmology at the Bascom Palmer Eye Institute and Interdisciplinary Stem Cell Institute.
“Understanding how to prevent damage and improve healthy function in these neurons may ultimately lead to sight-saving treatments for glaucoma and other degenerative eye diseases.”
Based on these findings, future glaucoma treatments may not only prevent blindness, but may actually restore vision. It may also help scientists determine which factors—such as genetics—make some people more susceptible to glaucoma.
The review is published in Ophthalmology.