I'm working in IT for a company, so I have to spend 8 & 1/2 hours of day in front of a computer. Can you suggest some exercises that will help rest my eyes?
The best "exercise" for your eyes is a 5-mins break: as often as you can. Here is a simple experiment you can do to better understand what it means for your eyes to focus on a screen for a long time.
So, while you are looking a movie, raise your hand parallel to the floor and keep it like that during the movie. How many minutes could you resist? Now realize that while watching a movie or looking at any other screen, your eyes are doing a similar job - muscles are tight and maintain the 3D-shape and position of your eyes to make them focus on the screen.
Now, think about this: is there any type of exercise that would allow you to keep your hand in a horizontal position for at least 1 hour continuously without any hurt or pain? Obviously, no. The same goes for eyes.
I share the same profession as you and have the same concerns. My advice would be to avoid computer eye strain by taking frequent breaks from the screen. I’ve been advised to get up from the pc every twenty minutes, or so. Frequent breaks give your eyes a chance to relax and reduces the strain. I’ve found that setting a regular schedule for breaks helps so that I know when to get up.
Eye exercise programs occupy a nebulous space somewhere between medical science and folk remedy. Most optometrists and ophthalmologists are dismissive of the types of programs promising that you can "throw away your glasses."
As for specific exercises, there are no scientific studies that show they help. There’s only anecdotal evidence. Your best bet is to avoid situations that strain your eyes.
I'm inclined to recommend Flux. It dims the blue component in your monitor. This gives it a slight reddish glow, but after 15 minutes, you're used to it.
The most amazing thing about it, is that if you've used it for 30 minutes or so, and turn it off, you're going to be in awe of how much regular monitor light hurts your eyes. I pretty much keep it on all day.