PORTLAND, Maine — Dr. Krishna Krithivas says in his 17 years of practicing optometry, the advent of screens big and small has dramatically changed the landscape of the patients he sees. They're getting younger, and are having more issues.

"In the past, I didn't see that many kids with dry eye but now we do. And I think a lot of that has to do with screen time mainly because when we're looking at screens, we don't blink as often as we would otherwise," Dr. Krithivas said. 

Another problem Dr. K sees in kids and adults is nearsightedness,also known as myopia. The reason?

 "Because we spend so much time on these screens, we're indoors. And there have been studies to show that the less outdoor time we have, the more myopic we can become," Dr. Krithivas answered.

So what are the signs when you need to take a break from the screen? When words start to blur or go in and out of focus. Another sign? When your eyes get dry and your head starts to ache.

"After about 20 minutes, it is great to take a break. And there's the old rule "20/20/20". Every 20 minutes, look at something 20 feet away for seconds. And minutes add up so at the end of the day, we don't have as much eye fatigue," Dr. Krithivas said. 

Parents: try to get your kids to take screen breaks too. When they do use them, keep the screen at an arms length. Also, turn the screens off a half hour before you hit the hay.

"When we're exposed to a lot of blue light before going to bed, it does make it more difficult to go to sleep. Melatonin is a chemical that's produced in our brain that helps us to sleep actually, and it interferes with the production of melatonin," Dr. Krithivas said.