Question: What is the best way to prevent and treat allergic conjunctivitis?
Answer: In order to prevent and treat allergic conjunctivitis you need to know that you're actually allergic to something. Without that information you can't avoid exposure to the substance you're allergic to. The way to make that determination is to visit your allergist -- they can do skin testing to determine what you're allergic to. There are a number of things you can be allergic to. For instance, a cat at home, dust and mite in your rugs, to pollens in the environment. There are ways of dealing with that. If it's indeed to pollen you can have a high efficiency, anti-allergic screen in your air conditioning unit. If it's dust and mite, you can actually expose your rugs to special shampoos that remove these allergens that cause your allergy.
Now once you know you're allergic and you try to avoid the allergen, if that doesn't work, you can indeed use new types of anti-allergic medications such as specially developed drops for reduction of allergy and its various effects on the eyes, as well as oral antihistamines.
So first, find out if you are allergic. Second, what are you allergic to and if avoiding this can reduce your allergic inflammation. If not, you need to try new medications to reduce the allergic inflammation.