If you work many hours in front of the PC (like me), then a good, healthy advice is to take a rest at determined intervals. This program, as its name suggests, is specially focused on taking care of our eyes. It will remind you to take a break and relax your eyes showing you pictures or making you do visual exercises.
EyeDefender is a simple program that, personally, I recommend you to download, specially if your job consists in working many hours a day in front of your PC. Once you've installed it on your system, the program will be available through an icon on the system tray. Making a click on the context menu, you can change some options on the settings window, for example, set the interval minutes between breaks, or set the break duration in minutes, according to your convenience.
Besides, for relaxing your eyes, you can select to show images from a determined folder on your PC, start a visual training exercise, or activate your default screen saver. Also, if you want, the program will only show a small pop up window on the system tray.