Eye allergy doctors generally use two kinds: antihistamines and mast cell stabilizers. If you use single-effect drugs, you should use two kinds, 6-8 times a day. Patanluo is double-effect, twice a day, which obviously shows the advantages. My grandfather is allergic to pollen in spring. He uses Patanluo in advance every year, and the symptoms of red-eye itching are quickly relieved. Grandpa likes spring outing very much, so he doesn't have to worry about eye allergies.