A common medication used to manage type 2 diabetes may offer a surprising benefit: potential protection against age-related vision loss. New research suggests that metformin, a widely prescribed drug, could slow the progression of age-related macular degeneration (AMD), a leading cause of irreversible blindness in older adults.
The findings, published on in BMJ Open Ophthalmology, stem from a retrospective analysis of eye images from approximately 2,000 individuals with diabetes who underwent routine eye screenings in Liverpool, United Kingdom, over a five-year period. Researchers at the University of Liverpool assessed the presence and severity of AMD in these images, comparing those taking metformin to those who were not.
The study revealed that individuals with diabetes over the age of 55 who were taking metformin were 37% less likely to develop the intermediate stage of AMD compared to their counterparts not on the medication. This intermediate stage is crucial, as it often precedes significant vision loss. “Most people who suffer from AMD have no treatment, so this is a great breakthrough in our search for new treatments,” said Nicholas Beare, MD, a clinician researcher at the University of Liverpool who led the research.
Understanding Age-Related Macular Degeneration
AMD affects the macula, the central part of the retina responsible for sharp, central vision. As the disease progresses, it can lead to blurred or distorted vision, making it difficult to read, drive, or recognize faces. There are two main types of AMD: dry and wet. The more common dry form progresses slowly, while the wet form is less frequent but can cause rapid vision loss.
Currently, treatments for AMD are limited, particularly for the dry form. Existing therapies often focus on slowing the progression of the disease rather than reversing damage. This makes the potential for a repurposed drug like metformin particularly exciting.
How Might Metformin Protect Vision?
While the exact mechanisms are still under investigation, researchers hypothesize that metformin’s potential benefits for AMD may be linked to its anti-inflammatory and anti-aging properties. It’s possible that metformin protects the delicate cells of the retina from damage. The drug is inexpensive and already widely available, making it a potentially accessible therapeutic option.
Important Caveats and Next Steps
It’s crucial to emphasize that this study is observational, meaning it demonstrates an association between metformin use and a reduced risk of AMD progression, but it does not prove a direct cause-and-effect relationship. Other factors could be at play. The researchers adjusted for variables such as age, sex, and duration of diabetes, but other confounding factors may exist.
the study population consisted solely of individuals with diabetes. It remains unclear whether metformin would have the same protective effect in people without diabetes. The researchers also lacked detailed information on metformin dosages and patient adherence to their prescriptions.
Dr. Beare emphasized the need for a rigorous clinical trial to confirm these findings. “What we need to do now is test metformin as a treatment for AMD in a clinical trial. Metformin has the potential to save many people’s sight,” he stated.
Metformin: A Familiar Medication with a Potential New Role
Metformin has been a cornerstone of type 2 diabetes treatment for decades. It works by improving the body’s sensitivity to insulin and reducing glucose production in the liver. This proves generally considered a safe medication, although common side effects can include gastrointestinal disturbances. In some cases, long-term metformin use has been associated with vitamin B12 deficiency.
The recent findings regarding AMD add to a growing body of research exploring potential off-label uses for metformin. Studies have also investigated its role in cancer prevention and anti-aging, though more research is needed to establish definitive benefits in these areas.
What Which means for Patients
At this stage, it is essential that individuals do not self-medicate with metformin in an attempt to prevent or treat AMD. The current findings do not warrant a change in treatment plans for either diabetes or AMD. Anyone concerned about their risk of AMD should consult with an ophthalmologist for a comprehensive eye exam and discuss appropriate preventative measures.
The research offers a promising avenue for future investigation and highlights the potential for repurposing existing drugs to address unmet medical needs. Further research, particularly well-designed clinical trials, will be critical to determine whether metformin can truly become a valuable tool in the fight against age-related vision loss.
