hello there. your eye is just getting tired and dry. and because of that you feel that itching sensation. take frequent breaks from your computer screen during which you need to just close your eyes for a minute or 2 so that the tear layer which had evaporated forms back. wash your eye with water. alternatively, there are many artificial tear drop preparations available. you can use those one drop 5-6 times a day. consult a ophthalmologist if your problem still persists. regards