Allergic conjunctivitis is an allergic reaction on the surface of the eyes.
Pollen, cat dander, and smoke are examples of allergens. The allergens may be in the air, such as smoke or plant pollen. Or they might be on your hands and get into your eyes when you touch your eyes. When your eyes are repeatedly exposed to allergens, the body reacts and produces antibodies. When allergens in the air contact antibodies on the eye, an allergic reaction begins.