For this reason I decided to adjust my computer's screen brightness according to the time of day (bright during the day, less bright at night). I soon found two programs that helped me with this goal, and I'll list them here so that others can benefit from them.
The first one is a free program called F.lux. When the sun sets, the program changes your computer's "color temperature" to a temperature that is more comfortable on the eyes. You'll need to give it your location so that it knows the time of sunset for you. It also serves as a reminder for the magrib prayer. :) When the color changes, you know it is time to pray.
The second program is also free and it is called MonitorBright. I found that f.lux helps but my monitor still stayed a little too bright. Therefore I now use this program to decrease brightness. Once you download it and open it, right click on its taskbar icon and enter a percentage (such as 20%). The bigger the percentage, the darker your screen will become.
The goal here is to make your monitor's brightness the same as the brightness of the room. Making the monitor too dark compared to the room's brightness will probably hurt your eyes.