(NBC)- "I like email my friends, I like instant message. I used to play video games with my brother," Barrett Malley said.
Like most teenagers, Barrett Malley did a lot of work up close near her eyes.
Recently her vision got worse, quickly.
"It'd be blurry from like looking at the screen," Malley said.
She tried glasses, then contacts ... especially for sports.
Barrett was diagnosed as near-sighted. And she's got lots of company.
Studies show a 66-percent increase in nearsightedness in the past 30 years.
Her optometrist, Dan Press, has a possible explanation why.
"The more time you spent doing things up close, that body may respond by limiting the amount of focusing you need to do up close. And when you're near sighted, you don't need to focus to see things up close, but things far away get blurry," Dr. Press said.
Barrett was prescribed something relatively new: Contact lenses worn only at night.
"While they're sleeping it's gently applying pressure to the front surface of the eye and then when they take it out, it maintains that new shape," Dr. Press said. "They can see clearly, usually up to 20/20."
Nearsightedness almost always gets worse over time in young people, even with glasses. These lenses are said to slow down that deterioration.
To protect your eyesight, there's the 20/20 rule.
"Every 20 minutes, you should look at something at least 20 feet away for 20 seconds," Dr. Press said.
"If I'm on my laptop or texting, I don't try to keep it close to my face. I try to put it here a little while and not be on it so much," Malley said.