Summarize this article in one sentence.
When you look at your monitor, you are essentially staring into a lamp. If you do this for extended periods, you can understand how this would fatigue your eyes. The default windows setting has an incredible amount of bright white areas. Keep in mind that white on a computer monitor is not like white on paper. A computer monitor is white because it's a lamp - a light source.

Summary:
Note that monitors have a backlight.