Common Eye Disease Among Older People Could Pose Serious Risk of COVID-19, Study Says

A recent study suggests that people with age-related macular degeneration, a common eye condition, could be at greater risk of getting infected and sick from COVID-19.

Age-related macular degeneration (AMD) happens when aging causes damage to the macula, the part of the eye that controls one’s ability to see fine detail in objects and recognize faces and colors. According to the National Institutes of Health (NIH), AMD is the leading cause of vision loss for older adults and affects some 11 million people in the United States.

According to a study published in December 2022 in the Journal of Clinical Medicine, growing evidence has shown that AMD is a greater risk factor for developing serious COVID-19 symptoms (25 percent) than Type 2 diabetes (21 percent) and obesity (13 percent).

The study’s authors, a team of researchers at Boston University, said this could be explained by a specific genetic activity occurring in both AMD and COVID-19 patients.

“Our findings add to the body of evidence for the increased risk of infection and mortality from COVID-19 among AMD patients. Our analysis lends credence to previously reported clinical studies that found those with AMD have a higher risk for COVID-19 infection and severe disease, and that this increased risk may have a genetic basis,” said Dr. Lindsay Farrer, the study’s co-author and medical geneticist at Boston University.

The team focused on what’s called a platelet-derived growth factor subunit B (PDGFB) gene. This gene encodes a platelet-derived growth factor (PDGF), which is involved in the abnormal blood vessel changes that occur in AMD. Upon analyzing data from tens of thousands of patients with AMD or COVID-19, as well as control groups, they found that the PDGFB gene is much more actively expressed in AMD patients than in AMD-free controls. They also found that PDGFB expression is significantly higher in patients with mid-stage COVID symptoms than in those with early-stage COVID symptoms.

“Considering variation across the genome as a whole, we observed a modest genetic correlation between AMD and COVID-19 infection, which indicates that some genetic factors contribute to risk for both diseases,” the authors wrote. “We did not observe a strong genetic correlation of AMD with COVID-19 critical illness and hospitalization.”

As a result, the researchers concluded that reducing PDGFB gene activity and lowering levels of PDGF concentration in blood may help reduce the severity of COVID-19, especially in elderly adults.

“Therapeutic strategies combining anti-VEGF therapy (a current treatment for AMD that limits blood vessel growth in the eye that can harm vision) with antagonists (drugs that bind to receptors) for blocking PDGF signaling have been considered even more effective than the single VEGF treatment and are currently under investigation in clinical trials,” said Dr. Manju L. Subramanian, a co-author of the study and professor of ophthalmology at Boston University.

The team said they need a bigger sample size for critical COVID illness and hospitalizations to better understand the shared pathology and risk factors that lead to worsened clinical outcomes in both disease states.

According to the NIH, people can be more prone to AMD as they get older. The risk for AMD is also higher for white people, smokers, and people who have a family history of the disease.

Research also shows that one may lower the risk of AMD or at least slow vision loss from AMD by quitting smoking, getting regular physical exercise, keeping blood pressure and cholesterol levels in check, and eating healthy foods such as leafy green vegetables and fish.