Great Sand Dunes National Park & Preserve, near Mosca in central Colorado (200 miles from Cortez, CO)
has the tallest sand dunes in North America, rising 750 feet off the valley floor.

From the desk of
Russ Quiring, O.D.
October 14, 2006

Computers & Eyestrain
Part I:  Your Monitor

This issue is the first of a 5 part series on computers and eyestrain.  This first part covers many of the things you can do with your computer monitor to decease eyestrain while using your computer.

Most people use a computer these days.  Whether it's at work, or home the computer is here to stay.  One problem that arises though is the way our eyes respond to the monitor.  They can get drained, irritated and make us down right miserable while we're trying to work on the computer. Drink all the coffee you want, it still won't keep your eyes from getting fatigued.  The monitor is causing your eyes to strain even though you don't realize it.  By making some changes with your computer monitor you will be able to perform better, with less eyestrain, at work or school.

Eyestrain associated with computer use isn't thought to have serious or long-term consequences, but it's disruptive and unpleasant.  Though you may not be able to change the nature of your job or all the factors that can cause eyestrain, you can take several steps to reduce the strain.
 

1. The number one thing you can do is to adjust your monitor's refresh rate.

Increase your Monitor Refresh Rate to 70-85 Hz (Read your monitor or computer hardware instruction manual to be sure your monitor is capable of this setting.)

Are you bothered by fluorescent lights?  So many of my patients complain about them.  These fluorescent bulbs flicker off and on at 60 Hz and many monitors are set at the same refresh rate!  Although humans cannot see fluorescent lights flicker, the sensory system in some individuals can somehow detect the flicker.  Ever since fluorescent lighting was introduced in workplaces, there have been complaints about headaches, eye strain and general eye discomfort.  These complaints have been associated with the light flicker from fluorescent lights.

The same is true for computer monitors; they flicker at the "refresh rate" we set them at.  Most of us don't see  this flicker as our eyes are usually not sensitive enough to detect it, but the flicker is there.  It is easy to notice this when looking at a monitor on a television show.  And as the monitor flickers, it can bother our eyes and cause eyestrain. Higher refresh rates are much less likely to cause eyestrain.

 

2. If you have Windows XP turn on ClearType.

ClearType delivers improved font display quality over traditional forms of font smoothing or anti-aliasing. It improves readability on color LCD displays with a digital interface, such as those in laptops and high-quality flat panel displays.  Readability on CRT monitors can also be improved.  You see better and see clearer with reduced eyestrain.

3. Increase the default font size or change the font face, size and color in the programs you use & in your internet browser.

You can also help reduce eye strain by making your default fonts larger and easier to see.  Monitors that use higher resolutions tend to have crisp but small text.  In Microsoft Word, for example, try Courier New instead of Times New Roman. (You can always change it back before you print).  For surfing the net, most browsers have an option to set font size to small, medium and large.  Try a different font size that makes your eyes more comfortable.

The size of your text should be about two or three times the size of the smallest text that you can read. Black text on a white background is usually the easiest to discern on a computer monitor.

4. Consider upgrading your monitor.

LCD monitors and flat screen monitors can greatly help reduce glare. Glare is a large contributor to eye strain.  Choose a monitor with a flat screen (i.e. LCD monitor) or purchase an anti-glare screen to go over your regular computer monitor.  Large monitors are easier to see as the font size can be increased.  Also make sure light from lamps or sunlight from windows does not reflect off your monitor.
 

5. Center your monitor in front of you.

For most workstations, the best position for your monitor is directly in front of you.  Putting the monitor to the left or right of your body can cause neck and shoulder pain due to twisting and awkward posture.
 

6. Position yourself an arm's length away.

Your monitor should be about arm's length away when you're sitting back in your chair, about 20 to 28 inches from your eyes. Sitting too close or too far from your screen can cause eyestrain.  If you have a large monitor - 20" or larger - you should sit slightly further away.

7. Position the top of your screen level with your eyes.

The ideal viewing height is to have your eyes level with an imaginary line across the screen, about 2"-3" below the top of the monitor.  This can be accomplished in one of two ways - either by either lowering your monitor or raising your chair.  If your screen is too low, you'll find yourself tilting your head forward to view the monitor (a common cause of neck pain).  If it's too high, you may have to tilt your head back, leading to neck and shoulder pain - and increasing the likelihood of glare from overhead lights (a common cause of headaches).
 

8. Tilt your monitor slightly upward.

Tilt the screen so that the base is slightly closer to you than the top.  This enables you to view the entire screen and the display more clearly.  Tilting the monitor downward isn't recommended unless necessary to reduce the glare of overhead lights or if your monitor is too high and can't be adjusted.
 

9. Where are your room windows?

Windows are a common source of glare on the monitor.  If you work in a room with windows, be sensitive to any reflections or glare that may show on your monitor and cause you to squint.  A great way to check for glare is to turn your monitor off and examine any reflections visible on it.  It is usually ideal to have your monitor facing 90 degrees from any window, not directly facing a window or directly opposite from a window.

Also, placing your monitor directly in front of a window can create an uncomfortable viewing situation if the brightness of the window behind the monitor is greater than that of the monitor.

10. Balance the brightness of your monitor and its surroundings.

While setting your monitor at its highest setting makes your programs look more vivid, it actually increases eyestrain.  You should adjust your monitor so that its brightness is approximately equal to the area directly behind it; the goal is to eliminate any contrast between the brightness of the screen and the area behind it.  Uneven brightness can cause headaches and vision issues (such as fatigue and squinting). You may need to adjust your screen brightness throughout the day if your workspace is lit by natural light.
 

11. Reduce undesirable glare.

If left uncorrected, glare will cause discomfort, eyestrain and headaches.  Try to reposition your monitor so that there's no glare on the screen (but avoid putting it in a position that's uncomfortable to view).  Also make sure the light from lamps or windows is not reflecting off your monitor.  If you can't avoid the glare by readjusting your monitor positioning, consider a high-quality anti-glare screen.

Extraneous light, or glare, is the greatest source of eyestrain for computer users. No matter where your computer is relative to a window, adjustable shades, curtains or blinds should be used to effectively control light levels throughout the day. Avoid facing an un-shaded window since the difference in brightness between the screen and the area behind it may be cause eye stress and discomfort.

12. Consider a swivel arm.

If you frequently interact with others, and placing your monitor in the recommended location would interfere with your interactions, consider purchasing a swivel arm.  Swivel arms enable users to maintain proper monitor location while in use and easily swing their monitors out of the ways when not in use.

 

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