Q: Is there a risk that tweens, teens and college students who spend so many hours peering at their small smartphone screens are doing permanent damage to their eyesight?

A: Almost 75 percent of 13- to 17-year-olds have smartphones, according to the Pew Research Center. That Pew report says “24 percent of teens go online ‘almost constantly,’ facilitated by the widespread availability of smartphones.”

As for the question of whether using that’s damaging their eyesight, “I’m not sure that it’s answerable,” says Dr. Steven Rubin, chief of pediatric ophthalmology at North Shore-Long Island Jewish Health System.

Rubin says he’s not aware of any study that specifically addresses the effects on the eyeballs of looking at a small screen, so there’s no way to know for sure.

Evidence would have to show, for instance, that suddenly the number of college students being diagnosed with myopia — nearsightedness — had gone up, Rubin says. In addition, data showing that myopia had progressed beyond high school graduation — the time when kids with myopia don’t usually get worse — would indicate an issue, he says.

“There’s one school of thought out there — not supported by science — that prolonged exposure may be making you more nearsighted,” he says. “I’m not aware of any data on that.”

Dr. David Epley, a spokesman for the American Academy of Ophthalmology, agrees that there isn’t evidence that focusing on a small screen causes anything more than temporary eyestrain or discomfort.

advertisement | advertise on newsday

Rubin recommends taking a break every few minutes from looking at a screen, whether a smartphone or a laptop or PC, and gazing into the distance. That’s for several reasons, including the fact that when people blink, they spread their tear fluid evenly across their corneas.

“When you’re concentrating, you blink less, and eyes can become dry or uncomfortable,” he says. “A break every few minutes is a great idea.”