Increase in nearsightedness associated with low lighting, not screens.

Myopia on the Rise: New Research Points to Possible Causes

Myopia, or nearsightedness, is becoming a major global issue, with the World Health Organization predicting that nearly half of the world’s population could be affected by 2050.

The heavy use of smartphones and other devices, coupled with extensive computer usage, is raising myopia risk by as much as 80%. However, recent studies indicate that low indoor lighting might also contribute to this growing problem.

For years, scientists have been trying to decode the complexities surrounding the cause of myopia. In lab settings, it can be induced by factors such as blurred vision or altered lenses. Interestingly, it seems spending time outdoors could serve as a counterbalance.

As noted by the American Optometric Association, myopia occurs when the eyeball stretches too much from front to back. This results in light focusing before the retina, causing distant objects to appear fuzzy.

Researchers at the State University of New York (SUNY) School of Optometry have discovered specific triggers linked to this eye growth. When focusing on close objects like a cell phone or a book, pupils tend to constrict naturally.

“In bright outdoor settings, the pupil constricts to safeguard the eye while ensuring adequate light reaches the retina,” explained Ursha Maharjan, a doctoral student at New York University’s Department of Optometry. “Indoors, when we focus on close items, our pupils may also narrow, but here it’s more about image sharpness than brightness. In dim conditions, this can diminish retinal illumination significantly,” she added.

This leads to the hypothesis that long periods of low-light close-up work can trick the retina into signaling the eye to grow. When in darker environments, constricted pupils significantly limit light exposure. As a result, the retina doesn’t receive enough stimulation to signal for growth cessation.

In contrast, the outdoors provides significantly brighter light, ensuring that even when pupils narrow for focus, the retina is still receiving strong signals that foster healthy eye development.

The research team acknowledged some study limitations, including a small sample size and challenges in measuring changes in the internal lens due to the pupils being too small under the bright conditions simulating outdoor light.

Researchers are hopeful that increasing indoor brightness during tasks typically associated with myopia could be a straightforward strategy to combat this global epidemic. “This isn’t the final answer,” stated José Manuel Alonso, MD, a Distinguished Professor at SUNY and lead author of the study. “However, it opens up avenues to explore how our visual habits, lighting, and eye focus interplay,” he remarked.