When we concentrate on something our blink-rate can drop to a quarter of its normal rate and the eye dries out; this is particularly common when using computers. Consciously practice giving good blinks, several times a day, and your subconscious blinking should also improve.
Sometimes the glands providing components of the tears may not be working well and wipes and/or hot massage may help. Your optician will be able to advise you (we are very happy to see you if you need further advice on this).
Try and add some moisture to your work environment if this is a problem; could you have a vase of flowers near you, or even a glass of water?
Try and get plenty of rest and eat well- oily fish like salmon and mackeral, and egg yokes are good for dry eyes.
Remember to consult your optician (and we are very happy to help- call us on 01382 224620).