itchy eyes is generally due to some kind of ocular surface allergy which can cause blood vessels on the conjunctiva to dilate and also might cause erosions on corneal surface if you rub which can be a cause of irritation. also it can affect your lid margin health and can cause swelling of lid glands which is called as anterior or posterior blepharitis which can again cause itch. sometimes mild dry eyes or even computer work excessively might cause these symptoms. all conditions have different treatment
Next Steps
so you should go to an eye specialist for complete examination of your corneal surface including a flurosceine staining slit lamp evaluation and lid margin assessment.
Health Tips
till you do that you can try putting any antiallergic eyedrop which has a lubricant and a non steroidal antiallergic component. Don't use steroidal eyedropper before proper and complete eye evaluation