Eye drops are great. They help lubricate dry eye. They get rid of red eye. They can also be used to treat a condition like diabetic edema, macular degeneration and may prevent vision loss after retinal vein occlusion. Two studies, one done at the University of New South Wales in Australia and another at Columbia University Irving Medical Center have shown promise as possible treatments for these conditions.
Research at the University of New South Wales in collaboration with the pharmaceutical company Exonate, which focuses on retinal diseases, developed eye drops that can help treat diabetic edema and macular degeneration. Scientists identified compounds that curb the growth factors that cause these diseases. What makes this treatment so special is that they are absorbed into the eye, so instead of having this compound injected into the eye, it can be delivered via eye drops.
A clinical trial of these eye drops is currently taking place with 48 diabetic patients who also have macular edema. Results from this are expected in early 2022.
As for the research at Columbia University, scientists developed an experimental therapy that targets a common cause of neurodegeneration and vascular leakage in the eye. This study looked at retinal vein occlusion, which occurs when a vein that drains blood from the retina is blocked as a result of a blood clot. This leads to blood and other fluid leaking into the retina, which damages the photoreceptors.
Current treatments for this condition include drugs that reduce both fluid leakage from blood vessels and abnormal blood vessel growth. These treatments aren’t the best since they require injections into the eye and, in most cases, they don’t prevent vision loss. The treatment developed at Columbia University targets an enzyme known as caspase-9. This enzyme is involved in programmed cell death. When programmed cell death works properly, it is a controlled process for getting rid of damaged or excess cells.
Scientists found that when blood vessels in laboratory mice are injured by retinal vein occlusion, caspase-9 becomes activated, goes out of control and triggers a process that damages the retina. When a caspase-9 inhibitor is delivered via eye drops, there was an improvement in many clinical measures of retinal function in the mice. In addition, the treatment reduced swelling, improved blood flow and decreased neuronal damage in the retina.
“We believe these eye drops may offer several advantages over existing therapies,” said Carol M. Troy, MD, PhD, professor of pathology and cell biology and of neurology in the Taub Institute for Research on Alzheimer’s Disease and the Aging Brain at Columbia University Vagelos College of Physicians and Surgeons who led the study. “Patients could administer the drug themselves and wouldn’t have to get a series of injections. Also, our eye drops target a different pathway of retinal injury and thus may help patients who do not respond to the current therapy.”
Researchers are planning to test the drops in persons with retinal vein occlusion in a Phase I clinical trial. They will also study whether the caspase-9 inhibitor can be used to treat other vascular injuries caused when the enzyme overreacts, such as diabetic edema and stroke.
Both of these studies show promise as a way to treat vision and retinal disorders and it is all via eye drops. These treatments have the potential to be good at the first drop.