Conjunctivitis, commonly known as “pink eye,” is an infection or swelling in your conjunctiva, which is a thin, transparent membrane that lies over the inner surface of the eyelid and covers the white part of your eye.
When you have pink eye, blood vessels in your conjunctiva become inflamed. This gives your eye the red or pink color that’s commonly associated with conjunctivitis.
There are different ways of classifying conjunctivitis.
Irritant or allergic conjunctivitis: An allergen or irritant, such as pollen or chlorine, comes into contact with the eye, triggering irritation and inflammation.
Infective conjunctivitis: Bacteria or a virus cause an infection.
Acute or chronic: In acute conjunctivitis, symptoms usually last 1-2 weeks, but they can last for 3–4 weeks. Chronic conjunctivitis lasts for over 4 weeks.