How to avoid a headache which monitor gives you
Most people are surprised when they hear their monitor flickers. They don’t ever realize their monitors hurt their eyes and give them headaches due to low refresh frequency.
The refresh rate is the number of times a display's image is repainted or refreshed per second. The refresh rate is expressed in hertz so a refresh rate of 75 means the image is refreshed 75 times in a second. The refresh rate for each display depends on the video card used.The bigger the refresh rate number, the less flicker you see on the CRT’s screen. As a rule of thumb, higher refresh rates are less likely to cause eyestrain.
An older refresh rate standard, developed by the Video Electronics Standards Association, was only 60 Hz. This refresh rate caused the display's image to flicker, causing eye fatigue and headaches in users. A new standard set the refresh rate to 75 Hz. It is believed that 70 Hz or higher eliminates the flicker. In Europe the legal minimum for health and safety is 72Hz (based on some study done years ago). In the US you can find people with low refresh rates all the time.When purchasing a monitor, look for a refresh rate of 75 to 85 Hz.
Some people are more sensitive to lower monitor refresh rates than others. As well, you may not notice it right away if you are looking directly at the monitor, but if you look out of the corner of one eye, a screen with a refresh of 60hz is crazy. Does it mean you have sore eyes? No. Because you have a really low refresh rate.
Human eyes are more sensitive to colour in the center of our vision, and to luminance in the periphery. Since flicker is a change in brightness (luminance), a monitor that seems okay when you look directly at it will flicker when seen on the edge of your vision. This is also why, in low light levels, you see something out of the corner of your eye, but then don't see anything when
you turn to look at it.
How to Change the Screen Refresh Rate of Your Monitor
1. Click Start, click Control Panel, click Appearance and Themes, and then click Display.
Alternatively, right-click the desktop, and then click Properties.
2. Click the Settings tab, and then click Advanced.
3. Click the Monitor tab, and then click the screen refresh rate that you want to use.
If you use a higher refresh rate, you can reduce the rate that your screen flickers; however, if you specify a refresh rate that is too high for your monitor, your screen may become unusable and your hardware may be damaged. If you increase your CRT's refresh so much that it gets close to its physical bandwidth limit (a.k.a. maximum pixel clock, typically measured in MHz), the image will get blurry. The blurriness is especially noticeable at higher resolutions, but it will affect your eyes to some extent regardless of what resolution you're using. And as if that weren't bad enough, it will significantly decrease the life of the CRT as well.
Because of this, as a general rule of thumb, it's safest to keep your vertical refresh rate at least 5Hz below the highest setting the OS offers for any given mode. For example, if you're running at 1024x768, and Windows offers up to 95Hz for that mode, pick something like 85Hz. Your eyes -- and your wallet -- will thank you.
If you pick a refresh rate and your monitor goes all blooey, don't panic. Just wait fifteen seconds and the system will switch back to the original settings. (If you have a Plug and Play monitor, it's supposed to report the refresh rates it supports, but sometimes that doesn't work.)
Note that not all refresh rates are available at all screen resolutions, so if you want to crank the rate higher, you may have to sacrifice resolution.
This really only applies to CRT monitors. Although Windows gives LCD monitors a refresh rate, the value doesn't really mean much.
Refresh rate is thing to look at when your screen gives you headache, but not the only one. Also try to set up the colors, and most important: contrast and brightness. If I recall it right, you should try to put the first as high as possible, and the second one as low as possible. Of course, don't bring the cursors to 100% and 0%, but to the highest and lowest values where the image displayed still looks natural.
As well, screen filters and protectors may be helpful.
Another point beyond refresh rate is to make sure you get your eyes checked regularly. At least once a year, twice if you can swing it. Even with a high refresh rate or a good LCD, staring all day at a point eighteen inches
7. duben 2008