A new study led by UA researchers reveals that age-related macular degeneration, a disease that causes blindness in 9 million older Americans, may be prevented or delayed by using a drug that treats motion-related diseases like Parkinson’s disease.
Brian McKay, the study’s lead researcher and an associate professor of ophthalmology and vision science at the UA College of Medicine, worked with a team of 13 researchers from around the country by analyzing data from 15 years and 87 million patients who had developed age-related macular degeneration, or AMD. AMD gradually destroys a person’s ability to read, write, drive, see in their upper field of vision and, eventually, see anything at all.
“It’s the most common cause of irreversible blindness on the planet,” McKay said.
McKay and his researchers looked for differences between patients who took the drug levodopa, also called L-dopa, which is a naturally produced chemical used to treat motion-related disease, and patients who did not.
“We asked the very simple question: If you’re taking L-dopa for whatever reason, do you get AMD?” McKay said.
The study revealed that patients who took L-dopa developed macular degeneration eight and a half years later on average compared to those who did not.
McKay began the collection of data back in 2000, when his studies of then-newly released research revealed that white-skinned people were six times more likely to develop AMD.
Brown pigments in the skin and eyes are more proficient at generating L-dopa, which is the chemical that helps keep the photoreceptors in the eye alive and functioning, said McKay. By taking L-dopa in pill form, patients were able to prevent or delay the development of AMD.
“Research points to this as a pathway to regulate and prevent this most common cause of blindness in adults,” said Murray Brilliant, the director of the Center for Human Genetics at the Marshfield Clinic Research Foundation in Wisconsin and a lead researcher in the study, in a press release. “Imagine telling patients we potentially have medication that will allow them to see and continue enjoying life, their family and perform everyday activities as they age. That is very powerful.”
McKay explained that while the new discovery opens new doors for research, it is not a surefire way to prevent the disease.
“I think this is step one in figuring out how to cure this disease,” McKay said. “It’s not done, but it certainly shows that we probably have the right path. We know what to do now.”
Michelle Valenti, a public health senior, said she thinks that since there is no cure for AMD, it would be ideal if it were preventable.
“We can’t control any of the hereditary components of the disease, but there are things that can increase the risk,” Valenti said. “I’m pretty sure smoking is a pretty huge risk factor, but also nutrition is important for preventing it.”
But besides preventing blindness in the people susceptible to the disease, being able to effectively combat AMD would bring other benefits to the public health sector.
“Lowering the number of cases could lower medical costs overall,” Valenti said. “It would also improve the overall quality of life for those who would have the disease.”
L-dopa, the precursor to dopamine production, rarely has side effects other than making patients feel “really happy.” McKay said that doctors will most likely begin prescribing patients the drug to combat AMD within the next month. This is despite the fact that it must still undergo clinical trials in order to become FDA approved as a drug repurposed to treat a different disease.
McKay said that clinical trials would finish within the next two years. In the meantime, he said he will be hard at work developing a new drug designed to specifically target and completely prevent AMD.
“I already have some pretty good ideas of what [the new drug] is going to look like,” McKay said.
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