noun. an overreaction by the immune system by normally harmless subjects called allergens
Eye allergies, also called allergic conjunctivitis, are quite common. They occur when the eyes react to something that irritates them (called an allergen). The eyes produce a substance called histamine to fight off the allergen. As a result, the eyelids and conjunctiva become red, swollen and itchy. The eyes can tear and burn. Unlike other kinds of conjunctivitis, eye allergies do not spread from person to person.
The most common eye allergy symptoms include:
red, swollen or itchy eyes
burning or tearing of the eyes
sensitivity to light