You seem to have allergic eye disease. In this condition the eyes react to some allergens in our environment which maybe due to pollution or cosmetics or seasonal pollens. Hence whenever your eyes are exposed to such allergens a chemical called histamine is released in the skin (conjunctiva) of the eye which gives us a sensation to itch. You may also be having coexistent cold in the form of running nose or sneezing during such epi odes. The only permanent solution is to find the allergen and avoid complete exposure to that allergen. However it wont be practically possible to do so. Hence to control your allergic symptoms you will require anti histaminic eye drops and tablets.