Avoid straining eyes by practicing good habits

After marathon hours on her phone and computer, Claudia Herrera's eyes just couldn't focus.

"My eyes would get red and then really irritated, and they really, really hurt," said Herrera, who begins her freshman year at Humboldt State University this year.

Eye fatigue or eye strain can be easily managed, but Dr. Hilary Hawthorne says poor habits can make existing vision problems worse.

The top causes: computer screens, smartphones and video games.

In addition to eyes, experts say to also pay attention to the muscles in the eyelids, neck and shoulders.

Hawthorne recommended Herrera sit between 20 and 28 inches away from a computer screen, which should be about four to five degrees below eye level.

The same eye-level rule applies to smart phone and tablets. Neck and shoulders should be relaxed, arms should be bent and elbows at the side.

Font should also be a comfortable size to read. And avoid looking up for long periods of time.

"It can lead to dryness, especially if there is a certain amount of humidity or dryness in the air, if there's air conditioning, people will have greater complaints," Hawthorne said.

Also, the American Optometric Association recommends what they call a 20-20-20 screen break. Every 20 minutes look at something 20 feet away for 20.

"If you're taking these visual breaks, it gives you the opportunity to refresh your visual system," Hawthorne said.

Another important tip: don't use electronic devices in the dark. Make sure there's another light source somewhere in the room so there isn't so much contrast and turn down the brightness on your screens.

Herrera knows in college she'll be spending a lot more time on her phone and computer, but she's learned the hard way to pace herself. She's headed to school with a pair of glasses.