IS NEARSIGHTEDNESS FUELED BY LOW LIGHT?

For years, everyone’s blamed smartphones and computer screens for the worldwide explosion in nearsightedness. But what if screens are just part of the picture? According to researchers at the SUNY College of Optometry, there’s another, sneakier culprit: dim indoor lighting, especially when paired with long stretches of close-up work.

Here’s the gist: whenever you’re hunched over your phone or a book in a softly lit room, your eyes are straining in ways you might not realize. The pupil, which works like a camera shutter, shrinks to sharpen your focus on nearby objects. But in dim light, that same constriction means the retina—the part of your eye that actually “sees”—is getting less light than it needs. Over time, this could lead to changes in the eye that make distant objects appear blurry. In other words, it’s not just the glowing rectangle in your hand, but how and where you use it.

A Modern Epidemic

Let’s talk numbers: nearly half of young adults in the U.S. and Europe now deal with myopia, and in parts of East Asia, it’s almost everyone. Genes play a role, sure, but this rise has happened too quickly for genetics alone to explain it. Something about modern life—our habits, our environments—is pushing our eyes in the wrong direction.

Scientists have known for a while that myopia can be “induced” in lab animals either by depriving them of visual detail or making them wear special lenses. Doctors fight back with all sorts of tricks: special glasses, eye drops, and encouraging kids to spend more time outside. But why do all these different things seem to help? The new theory from SUNY’s team tries to tie it all together.

A Fresh Look at Light and Focus

Here’s what the researchers think is really going on: the common thread isn’t just staring at stuff up close, but what happens to your eyes when you do it in low light. Under bright sunlight, your pupils get small, but there’s still plenty of light hitting the retina. When you’re inside, craning over your phone or a textbook with the lights down, your pupils narrow not for brightness, but because your eyes are working hard to keep things sharp up close. The result? The retina gets even less light, and that might mess with normal eye development.

The study also found that negative lenses—the kind used to correct or even induce myopia in experiments—make the problem worse. When your eyes focus up close for long stretches, especially with strong lenses, your pupils stay pinched, cutting down the light to your retina even more. Once someone is already nearsighted, these effects get even more pronounced.

What This Means for Preventing Nearsightedness

If this theory holds up, it could shake up how we think about both preventing and treating myopia. The main takeaway: your eyes seem to need plenty of light, especially when doing close-up work. That might mean turning up the lights indoors, using special lenses to ease eye strain, or—best of all—spending more time outside, where natural light does the work for you.

As for treatments, the researchers suggest that anything that reduces how much your pupil has to constrict when you focus up close could help. That includes multifocal glasses, certain eye drops (like atropine), or just taking more frequent breaks to look at faraway things.

But, as the lead researcher Jose-Manuel Alonso points out, this isn’t the last word. “This is a testable hypothesis that pulls together a lot of loose threads,” he says. “It gives us a new way to think about how light, habits, and eye focus work together. There’s still more work to do—but it’s a promising start.”

So next time you’re scrolling late at night with the lights low, remember: your eyes might be working harder than you think.