Dim Indoor Light May Drive Nearsightedness Epidemic

New research suggests we've been looking at nearsightedness all wrong, and the fix might be as simple as turning on more lights.

For years, parents have worried that phones and tablets are ruining their kids' eyesight. But scientists at SUNY College of Optometry now believe screens aren't the main problem. Instead, it's what happens when we focus on nearby objects in poorly lit rooms.

The numbers tell an urgent story. Nearly half of young adults in the United States and Europe now have myopia, and in parts of East Asia, that number climbs to 90 percent. That's a dramatic jump in just a few generations, far too fast to blame genetics alone.

Dr. Jose-Manuel Alonso and his team discovered something fascinating about how our eyes respond to different conditions. When we focus on something close in dim light, our pupils constrict to sharpen the image. But that constriction dramatically reduces how much light reaches the retina, potentially triggering changes that lead to nearsightedness.

"Myopia has reached near-epidemic levels worldwide, yet we still don't fully understand why," said Alonso, SUNY Distinguished Professor and senior author of the study scheduled for publication in Cell Reports. "Our findings suggest that a common underlying factor may be how much light reaches the retina during sustained near work, particularly indoors."

The research helps explain why seemingly different myopia treatments all work. Atropine drops, multifocal lenses, and spending time outdoors may all succeed because they help maintain healthy light levels reaching the retina. They reduce pupil constriction during close-up work.

Doctoral student Urusha Maharjan explained the contrast: "In bright outdoor light, the pupil constricts to protect the eye while still allowing ample light to reach the retina. When people focus on close objects indoors, such as phones, tablets, or books, the pupil can also constrict, not because of brightness, but to sharpen the image."

The Bright Side

This discovery offers families a surprisingly simple strategy. Instead of banning devices entirely, parents might just need to brighten the room when kids do homework or use tablets. The research suggests that maintaining good lighting during close-up activities could help protect developing eyes.

The theory also explains why time outdoors helps so much. When children play outside, they naturally look at distant objects in bright light, giving their eyes the healthy retinal stimulation they need. That's true whether they're reading a book outside or chasing a soccer ball.

Alonso emphasized this isn't the final answer, but it offers a testable path forward. The hypothesis brings together many puzzle pieces that previously seemed unconnected, all grounded in measurable physiology.

For the millions of families watching myopia rates climb, this research brings genuine hope that a global health challenge might have a remarkably achievable solution.