ACUTE CONJUNCTIVITIS: DEFINITIONS
A red eye is the most common presenting complaint seen by primary care physicians. The clinical term red eye is applied to a variety of distinct infectious or inflammatory ocular disorders that involve one or more tissue layers of the eye. In some cases, a red eye signals a vision-threatening condition that requires urgent referral to an ophthalmologist. The majority of cases, however, is benign and can be treated by primary care physicians. Conjunctivitis is the most common cause of the red eye in the community setting. The conjunctiva is a thin mucous membrane with both bulbar and palpebral portions. The palpebral portion of the conjunctiva covers the inside surface of the eyelids, while the bulbar portion covers the surface of the globe up to the limbus (the junction of the sclera and cornea). Underneath the conjunctiva lie the episclera, sclera, and uveal tissue layers. The conjunctiva is generally transparent, but when it is inflamed, as in conjunctivitis, it appears pink or red at a distance. The superficial blood vessels within the conjunctiva become engorged (termed injection), and edema of the conjunctiva may become apparent.*27/348/5*
