Why does my monitor hurt my eyes?

Q A friend is suffering severe eye strain from her monitor. We have tried changing the brightness and contrast settings and using a screen filter but without success.

We would rather not go to the expense of a new screen and were hoping that there might be some setting that can be changed to improve matters. The computer runs Windows XP.
Alfred Miller

A You don’t specify the exact kind of monitor. Older CRT monitors, which are quite rare these days, can cause eye strain if they are set up wrongly.

They are easy to identify because they are very deep; anything more than six inches deep is a CRT monitor.

CRT monitors work in by firing a beam at the inside of the front of the monitor to produce the image one dot (or pixel) at a time. This normally happens fast enough that your eyes don’t notice.

The number of times the screen is update every second is known as the refresh rate. A refresh rate of 70Hz means the screen is updated 70 times every second. As the resolution of the screen is increased, the refresh rate drops, and settings of 60Hz or below can cause eye strain.

Don’t try to increase this without checking the manual first; setting too high a refresh rate can damage a monitor. If this is the case try using a lower resolution. Right-click on the Desktop and then left-click on Properties. Left-click on the Settings tab and move the slider to the left to reduce the screen resolution. Click on Apply to preview the change. Click on OK if you are happy with it and try the new resolution to see if that eases the eye strain.

LCD monitors are immune to this problem but they can cause eye strain if everything on screen is too small.

For example, we once saw a 16in LCD monitor with the same resolution of 17in and 19in monitors. Although there were no refresh-rate problems, the fact everything was much smaller lead to eye strain more quickly than using a regular monitor.

If this is the case, it is possible to tell Windows to make everything bigger. Click on the Advanced button in the Settings tab of Display Properties. Click on the General tab if it does not appear automatically. Click on the dropdown menu and select Large Size (120 DPI). Click on OK in the warning that appears and then in the Display options windows. Restart the computer and all the fonts and icons should now be bigger, hopefully making the computer easier on the eyes.

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