Hi Pink kittycat,
When working on a computer you tend to blink 3 times less than normal and that can cause your eyes to feel dry and gritty.
It is really important that you incorporate changes of activity into your daily routine so that you are getting up from your computer at least once every 30-40 mins. Its also really important for back, neck, shoulders etc. Simple things like going to toilet, getting water, walking over to a colleagues desk.
You can also get a natural tear drop solution in any chemist for €3-4 which will help to lubricate your eyes.
It's a good idea as well to have your eyes tested every 2 years to maintain good eyesight and eyehealth.