Staring at your computer screen, smartphone, video game, or other digital devices for long periods won't cause permanent eye damage, but may cause your eyes to feel dry and tired.  Normally, humans blink about 18 times per  minute, but studies show we blink half that often while using computers and other digital screen devices.  Here are some tips to reduce eyestrain from computer use:

• Sit about 25 inches from the computer screen and position the screen so your eye gaze is slightly downward.
• Reduce glare from the screen by lighting the area properly; use a screen filter if necessary.
• Every 20 minutes, shift your eyes to look at an object at least 20 feet away, for at least 20 seconds (the 20-20-20 rule).
• Use artificial tears intermittently to refresh your eyes when they feel dry.
• Take regular breaks from computer work, and try to get enough sleep at night.  

If you have to be at your computer for an extended period of time, take regular rest breaks if possible.  If your eyes begin to feel irritated and tired, apply a washcloth soaked in warm water to your closed eyelids for a few minutes.  If you are a contact lens wearer, give your eyes a break and switch to glasses during a "marathon" computer session.