This document defines and classifies conjunctivitis, discussing its various causes including viral, bacterial, allergic, and other non-infectious origins. It describes the signs and symptoms, treatment, and when referral is necessary for different types of conjunctivitis such as viral, bacterial, hyperacute, chronic, and allergic conjunctivitis. It also briefly discusses other eye lesions including keratitis, uveitis, episcleritis, scleritis, hordeolum, chalazion, and pterygium.