Atraumatic Red Eye

Atraumatic red eye

The atraumatic red eye is a common ED presentation that ranges from benign, self‑limiting conjunctivitis to sight‑threatening conditions such as corneal ulceration, anterior uveitis and acute angle‑closure glaucoma. The ED clinician’s priorities are to identify red flags that require urgent ophthalmology review; perform a focused bedside assessment (visual acuity, pupils, motility, fluorescein staining, IOP when safe); initiate condition‑specific temporising measures; and apply antimicrobial stewardship and public‑health advice.

This section summarises relevant anatomy, a practical ED assessment framework, important differential diagnoses, immediate management priorities, when to swab or refer, and common pitfalls.

Anatomy and pathophysiology (concise)

• Conjunctiva: mucous membrane over sclera and lining lids - site of conjunctivitis and subconjunctival haemorrhage.
• Episclera: superficial vascular plexus - inflammation → episcleritis (mobile vessels).
• Sclera: deep fibrous coat - scleritis involves deep vessels and often a bluish hue and severe pain.
• Cornea: avascular, transparent anterior surface - epithelial and stromal disease cause pain, photophobia and reduced vision; epithelial defects stain with fluorescein; branching dendritic ulcers suggest herpes simplex.
• Anterior uvea (iris and ciliary body): inflammation → anterior uveitis (iritis) with perilimbal injection, photophobia and anterior chamber cells/flare.
• Aqueous dynamics: produced by the ciliary body, drains via trabecular meshwork/Canal of Schlemm. Angle closure obstructs outflow → raised IOP (acute angle‑closure glaucoma).

Triage - red flags that prompt immediate ophthalmology escalation Urgent senior/ophthalmology...