Age-related macular degeneration (AMD) is a leading cause of vision loss for adults over 50 in the United States.
According to estimates from the National Eye Institute, about 11 million people in the U.S. are affected by some form of AMD, and this number is expected to double by 2050 due to the aging population.
While AMD doesn’t cause complete blindness, it damages central vision, making daily activities like reading or recognizing faces challenging.
There are two types of AMD: dry (atrophic) and wet (neovascular). Dry AMD is the more common type, accounting for 80–90% of cases. It occurs when the macula, the part of the eye responsible for central vision, thins with age, causing deposits to form that slowly impair sight.
Wet AMD, although less common, is more serious and responsible for most cases of advanced vision loss. In this form, abnormal blood vessels grow under the retina, leaking blood or fluid and causing rapid damage.
Currently, there is no cure for dry AMD, though lifestyle changes and supplements can help slow its progression. Wet AMD can be treated with injections into the eye to slow its damage, but vision loss that has already occurred cannot be reversed.
These treatments, while helpful, are often expensive, invasive, and limited in effectiveness. Researchers are, therefore, searching for more accessible treatments, and one promising candidate is metformin.
Metformin is a medication widely used to treat type 2 diabetes. Recently, researchers have been interested in it because of its potential anti-aging properties.
Studies have shown that people taking metformin for diabetes have a lower incidence of age-related diseases, such as heart disease, cancer, and cognitive decline. This has led scientists to wonder if it might also help prevent AMD.
Dr. Dimitra Skondra, an ophthalmology professor at the University of Chicago, has been at the forefront of this research. She believes metformin, being inexpensive and safe, could be an ideal treatment for AMD.
The drug has been in use for over 30 years and has a strong safety profile. “We need something noninvasive and safe to use in the early stages of AMD, and metformin fits perfectly into that role,” Skondra says.
In 2021, Skondra and her team analyzed data from a large health insurance database. They focused on people over the age of 55 who had been diagnosed with AMD, comparing them to those without the condition.
Their study, published in JAMA Ophthalmology, found that patients taking metformin had a reduced risk of developing AMD. This protective effect seemed to be stronger in people without diabetes.
Her team followed up with another study in 2023, showing that metformin lowered the risk of both wet and dry AMD in people without diabetes, further strengthening the case for the drug’s potential use beyond diabetes treatment.
In addition, Skondra’s research published in the journal Retina earlier this year showed that metformin also reduced the chances of developing wet AMD, particularly in patients without diabetic retinopathy (a condition that affects the eyes due to high blood sugar).
One of the most challenging forms of AMD is geographic atrophy (GA), an advanced form of dry AMD that leads to the death of retinal cells and severe vision loss. Current treatments for GA require frequent injections, have limited success, and come with high costs.
Skondra’s recent analysis, published in Investigative Ophthalmology & Visual Science, found that metformin lowered the odds of developing GA by 47%, offering a potential breakthrough in treating this difficult condition.
While the exact mechanism of how metformin protects against AMD is unclear, it is likely tied to its overall anti-aging effects.
Studies in animals have shown that metformin can reduce oxidative stress, improve the function of mitochondria (the cell’s energy producers), and reduce inflammation—all processes linked to aging.
One especially interesting possibility is that metformin works by improving the gut microbiome, the community of microbes living in our digestive system.
In a study with mice, Skondra’s team found that metformin reduced the size of AMD-related lesions and lowered levels of inflammation. The drug also improved the gut health of these mice, increasing the presence of beneficial bacteria.
Interestingly, when the drug was tested in germ-free mice (those without gut bacteria), it did not have the same protective effects, suggesting that the gut microbiome plays a key role in metformin’s benefits.
These findings are exciting enough to justify clinical trials in humans, Skondra says. Testing metformin on people over the age of 55, both with and without diabetes, could help determine if it truly prevents AMD, particularly in its more advanced forms.
Given the growing number of people at risk for AMD, a safe, inexpensive drug like metformin could have a significant impact.
“Many of these people are just entering retirement and looking forward to enjoying life,” Skondra explains. “If we can prevent the vision loss caused by AMD, it could drastically improve their quality of life.”
If you care about diabetes, please read studies about a cure for type 2 diabetes, and these vegetables could protect against kidney damage in diabetes.
For more information about diabetes, please see recent studies about bone drug that could lower risk of type 2 diabetes, and results showing eating more eggs linked to higher risk of type 2 diabetes.
The research findings can be found in Investigative Ophthalmology & Visual Science.
Copyright © 2024 Knowridge Science Report. All rights reserved.
