We all know how important it is to keep our bodies fit by doing things like going to the gym, jogging, and swimming. But, did you know that you can exercise your eyes as well? Eye exercising will keep your eyes healthy and help minimize eyestrain.

[edit] Steps

Sit comfortably on a chair. Rub your hands together until they feel warm. Close your eyes and cover them lightly with your cupped palms. Avoid applying pressure on your eyeballs. Place your palms so that the nose remains uncovered, and the eyes remain behind the slight hollow of the palms. Make sure that no light rays enter the eyes, and leave no gaps between fingers or between the edge of the palms and the nose. You may still see other lingering traces of colors. Imagine deep blackness and focus on the blackness. Take deep breaths slowly and evenly, while thinking of some happy incident; or visualize a distant scene. After your eyes see nothing but blackness, remove your palms from your eyes. Repeat the palming for 3 minutes or more.
Close your eyes tightly for 3-5 seconds, then open them for 3-5 seconds. Repeat this 7 or 8 times.
Close your eyes and massage them with circular movements of your fingers for 1-2 minutes. Make sure you press very lightly; otherwise, you could hurt your eyes.
Press three fingers of each hand against your upper eyelids, and hold them there for 1-2 seconds, then release. Repeat 5 times.
Sit and relax. Roll your eyes clockwise, then counter-clockwise. Repeat 5 times, and blink in between each time.
Sit about 6 inches (200 mm) from the window. Make a mark on the glass at your eye level (a small sticker, black or red, would be perfect). Look through this mark and focus on something far away for 10-15 seconds; then focus on the mark again.
Hold a pencil in front of you at arm's length. Move your arm slowly to your nose, and follow the pencil with your eyes until you can keep it in focus. Repeat 10 times.
Look in front of you at the opposite wall and pretend that you are writing with your eyes, without turning your head. It may seem difficult at first, but with a bit of practice it is really fun. The bigger the letters, the better the effect.
Imagine that you are standing in front of a really big clock. Look at the middle of the clock. Then look at any hour mark, without turning your head. Look back at the center. Then look at another hour mark. Do this at least 12 times. You can also do this exercise with your eyes closed.
Focus on a distant object (over 150 feet or 50 m away) for several seconds and slowly refocus your eyes on a nearby object (less than 30 feet or 10 m away) that's in the same direction. Focus for several seconds and go back to the distant object. Do this 5 times.
Focus on an object in the distance (as far as possible) with a low contrasting background. Do this for a few minutes every half hour or so. This does not improve your vision, nor does any other technique. It can, however, maintain your best eyesight level during the day and prevent significant further vision deterioration.

[edit] Tips

It's more important to do the exercises regularly than to do them for a long time. Even 30-60 seconds of eye movement every hour is very helpful. For example, when your computer takes its sweet time to do something, most people just stare at the poor thing and waste the time, but you can make a few circles with your eyes. Even the first day you do this, you should notice that, when you finish working, your eyes aren't as tired as usual.
Taking short breaks from near work (e.g. staring at a computer monitor) to stare out to the distance also relieves some strain.
Palming is a good method to help your eyes feel better. You close your eyes and put you palms over them, this will rest your eyes.
Blink the eyes many times.
Splash your eyes with cold water repeatedly when feasible, and especially when your eyes are strained.

[edit] Warnings

Consult your optometrist (eye doctor) before doing any of these exercises. The last thing you want to do is add further strain to your eyes, or damage them permanently.
When doing these exercises, make sure that you're not facing anybody, or that they know you're doing eye exercises. Otherwise they might think you've gone nuts.
Extensive peer reviewed research has shown that visual clarity is not improved by exercise. Some people have weakness in the ability to turn their eye in or out. You may have esotropia (eye naturally turned in) or exotropia (eye naturally turned out). Exercise may help these conditions.
Doing these exercises when you wear contacts may cause them to suction to your eyeball. They might also move around and possibly become folded and/or dislodged, which can be extremely uncomfortable as well.
Do not apply pressure on your eyes.
Wash your hands before doing these exercises to avoid getting irritants in your eye.