“Red eye” is a common presenting complaint in ambulatory practice. A small percentage of patients with red eye need urgent ophthalmological referral and treatment, but the vast majority can be treated by the primary care clinician. Conjunctivitis (allergic or viral) is probably the most common cause of red eye in the community setting.
●Patient evaluation
Patient history, measurement of visual acuity, and findings on penlight examination are important features in determining the cause and management of red eye. The history and ocular examination provide guidance in the decision about whether to refer the patient for ophthalmologic evaluation. The history should include whether vision is affected, whether there is a foreign body sensation, whether there is photophobia, whether there is a history of trauma or contact lens use, and whether discharge is present. Visual acuity of each eye should be assessed in all patients using a Snellen chart or alternative means. Penlight examination should include pupil size and reactivity to light, the presence and nature of discharge, the pattern of redness, and the presence of corneal opacity, hypopyon, or hyphema.
●Causes and management
The differential diagnosis of the red eye includes benign conditions and serious conditions that require ophthalmologic evaluation.
●Indications for emergency ophthalmic evaluation
In the patient with red eye, if vision is unaffected, the pupil reacts, there is no objective foreign body sensation or photophobia, and there is no corneal opacity, hyphema, or hypopyon, it is reasonable for the primary care clinician to manage the condition. The following are indications for emergency referral for ophthalmologic evaluation:
•Unilateral red eye with pain, nausea, and vomiting
•Hyphema or hypopyon
•Visual deficit
•Corneal opacity or infiltrate that stains with fluorescein.
