Take frequent breaks. Go for a walk. Cut down on harsh lighting. Depending on how old you are that would make a difference. If you're young (not like me) I doubt you'll need glasses. Just don't overdo it. Best results come from being relaxed enough to get into what you're doing. Remember...too too long in front of the computer = crankiness. Not good.

Uvah's right

If you need or already wear glasses you can have a set made for a specific focal length that matches your the distance from your eye to the computer screen. Also, larger screens are generally easier to read so you avoid as much eye strain.

There are several simple solutions.

Don't be too close.

Don't be too far away.

Have the screen centre slightly lower than your natural eye-line. [below horizon].

Adjust brightness and contrast to be less stark/harsh.

Check [particularly with CRTs] that the monitor refresh rate is at least 75hz and thus [relatively] flicker-free/stable.

Google for ergonomics, posture and vision.

Most importantly...no-one actually HAS to sit in front of a computer for hour everyday.... Slavery is prohibited [mostly] and Occupational Health and Safety [or their equivalent] can prosecute employers who fail to ensure safe work practises....;)

This might be useful

http://www.stereopsis.com/flux/

How about you try using both eyes........

Refresh rate to accepted levels as follows:

2048 x 1536 @ 68Hz
1920 x 1440 @ 73Hz
1856 x 1392 @ 75Hz
1600 x 1200 @ 87Hz
1280 x 1024 @ 101Hz

Only CRT actually. As far as I know, screen refresh on LCD/TFT is not an issue.

That's a sweet piece of software! Thanks.

I have been taking online classes for the last 6 months.  And so i have been spending a lot of time reading from the screen..  The books come in pdf.  I have suffered from head aches to blurry vision especailly during cram sessions for tests. 

This were I found help

But even then this didn't help when it came to my cram session time  so went out and purchased a pair of GUNNAR Optiks glasses.  GUNNAR digital performance eyewear with i-AMP™ lens technology is specifically built to give even the most demanding computer user an immediate and noticeable visual advantage in the short term, and provide superior optical performance in the long term.  I have to say these have helped with the headaches and the eye fatigue.

If you are sensitive to light(as I am),Firefox has a plugin called Kill Bright Backgrounds...you can set the amount and range of backgrounds affected.

Its indespensible to me.

I can't seem to find that extension, got a link?

Agreed Kill Bright Backgrounds is excellent.  

http://dourob8.100webspace.net/extensions/killBrightBackgrounds.xpi

all great ideas here....

simple eye exercises also help strengthen the muscles.....

eye exercises 1

eye exercises 2  for example...

but, in a nutshell....don't forget to blink....we tend not to when concentrating...and eyes get dry...

rolling the eyes around...and figure 8 good....and....look up...then centre...down...then centre...right...then centre...left...then centre.....etc..you get the idea.....strengthens the muscles.

another thing that is simple to do....is, if you are sitting next to a window....look out every now and again....and focus on something in the distance....

the colour green...is also the most relaxing on your eyes.....try it out...looking at grass...(old yoga trick)

if I'm working in Word alot....I change the background from white....to the softest pale sage green....much less harsh on your eyes.

have a soft lamp next to the 'puter as well....fluoro lights are very harsh.....

this should protect both of 'em....

Nice advice guys/gals. I find that I have to actually get up and leave my office during work at about 15 min. intervals. I just can not handle staring at the screen or sitting for that long at any given time. My ADHD may also be part of this, but....who knows....LOL

Certain solution............sell computer!

You could use really big fonts.

So, you're a vampire?  mmuuuaahahahahh

I didn't realise there was a difference