Context and Definition

Context

The red eye is a common presenting complaint to the emergency department (ED).

Although accurate figures are not available for EDs, the acute red eye accounts for approximately 1-4% of all primary care consultations. [1,2]. Its presence may indicate one of a wide range of acute eye problems, from relatively minor conjunctivitis to potentially eyesight-threatening acute angle closure glaucoma.

The emergency physician must become familiar with all the different causes of a red eye and how to differentiate between them.

Definition

The red eye is a term used to describe the reaction of the eye to exogenous or endogenous inflammation or infection. It encompasses inflammatory processes originating in the conjunctiva, episclera, sclera and anterior uveal tract.

Non-traumatic subconjunctival haemorrhage is also commonly included in the causes of red eye [3], although it is usually not part of an inflammatory or infective process.