A new study from Johns Hopkins Medicine, supported by the U.S. National Institutes of Health has found that cigarette smoke doesn’t just irritate the eyes—it accelerates their ageing at the genetic level.

Published in the ‘Proceedings of the National Academy of Sciences,’ researchers revealed how smoking triggers epigenetic changes in retinal cells, effectively reprogramming them in ways that mirror age-related macular degeneration (AMD)—the world’s leading cause of vision loss in adults over 50.

Smokers are already known to be four times more likely to develop AMD. But the biological “how” has remained murky. “Smoking is often assumed to accelerate ageing by releasing tissuedamaging molecules called free radicals,” said James T. Handa, M.D., chief of the retina division at the Wilmer Eye Institute.