A widely used diabetes medication may offer an unexpected benefit beyond controlling blood sugar.
Researchers have discovered that metformin, one of the world’s most commonly prescribed diabetes drugs, may help protect older adults from developing a serious eye condition that can lead to blindness.
The new study was carried out by researchers at the University of Liverpool and published in BMJ Open Ophthalmology. The findings suggest that people over the age of 55 with diabetes who took metformin were significantly less likely to develop a more advanced form of age-related macular degeneration, commonly known as AMD.
Age-related macular degeneration is the leading cause of vision loss in many Western countries. The condition affects the macula, a small but very important area in the center of the retina at the back of the eye.
The retina acts like the film inside a camera, receiving light and sending visual information to the brain. The macula is responsible for sharp central vision, which people use for reading, recognizing faces, driving, and seeing fine details.
As people grow older, changes can occur in the macula that gradually damage central vision. In its early stages, AMD may cause few or no symptoms.
As the disease progresses, people may notice blurred vision, dark spots in the center of their sight, or difficulty reading and recognizing faces. Although AMD does not usually cause complete blindness, it can greatly affect a person’s independence and quality of life.
There are two main forms of advanced AMD. One type is called geographic atrophy, often referred to as dry AMD. In this condition, cells in the macula slowly die, leading to progressive vision loss.
The second type is called wet AMD. This form occurs when abnormal blood vessels grow underneath the retina and leak blood or fluid, causing damage to the macula.
Treating advanced AMD remains a major challenge. In the United Kingdom and Europe, there is currently no approved treatment for geographic atrophy.
Although treatments are available for wet AMD, they usually involve repeated injections directly into the eye. These treatments can slow vision loss but are expensive, uncomfortable, and often require frequent hospital visits.
Because of these limitations, researchers around the world have been searching for new ways to prevent AMD from developing or slowing its progression before serious vision loss occurs.
In the new study, the Liverpool team examined the eye health of 2,000 people who participated in the city’s diabetic eye screening program over five years. The researchers used detailed photographs of the retina to look for signs of AMD and monitor how the disease changed over time.
The team then compared people who were taking metformin with those who were not using the drug. They also took into account other factors that could influence the results, including age, sex, and how long participants had been living with diabetes.
After making these adjustments, the researchers found a clear difference between the two groups. People who took metformin were 37 percent less likely to develop intermediate or more advanced forms of AMD during the five-year period. The statistical analysis showed that the odds of disease progression were significantly lower among metformin users.
Scientists had previously suspected that metformin might help protect eye health. Some earlier studies had hinted at a possible benefit, but much of that research relied on medical records or insurance databases rather than direct examination of the eyes.
The new study is the first to use actual retinal photographs to assess and grade AMD, making the findings more reliable and providing stronger evidence for a possible protective effect.
Dr. Nick Beare, the lead researcher and an eye specialist, described the results as highly encouraging. He explained that most people with AMD currently have few or no treatment options.
Because metformin is already widely used, relatively inexpensive, and has a well-understood safety profile, it could potentially become an important tool for protecting vision if future studies confirm the findings.
The researchers emphasize that more work is still needed. This study cannot prove that metformin directly prevents AMD because it was observational. Clinical trials will now be needed to determine whether the medication truly protects the eyes and whether it could be used specifically to prevent or treat AMD in people with and without diabetes.
Even so, the findings offer new hope for millions of older adults who are at risk of losing their vision. An affordable medicine that has been prescribed safely for decades may one day help prevent one of the most common causes of blindness.
If future clinical trials confirm these results, metformin could lead to a major change in the way doctors approach age-related macular degeneration and help many people preserve their sight as they age.
If you care about diabetes, please read studies about diabetes and vitamin B12, and the right diet for people with type 2 diabetes.
For more health information, please see recent studies about how to eat smart with diabetes, and turmeric and vitamin D: a duo for blood pressure control in diabetic patients.
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