Presentations / Red eye
The red eye
Three questions, then the pattern of redness.
Most red eyes are conjunctivitis and most of the rest are not. Ask about pain, vision and photophobia; any yes moves the eye out of the benign column. Then read where the redness is, what the cornea looks like, what the pupil is doing, and what is in the chamber.
A watery red eye after a coldOpen in the atlas
The three questions
Is there pain (not grittiness: pain)? Is the vision reduced? Is there photophobia? Conjunctivitis and a subconjunctival haemorrhage answer no to all three. Keratitis, uveitis, scleritis and angle closure answer yes to at least one, and each needs the slit lamp the same day.
What separates them
The pattern of injection, the cornea, the pupil and the chamber sort the serious causes from each other.
| Pain | Vision | Photophobia | Injection | Cornea | Pupil | Discharge | Urgency | |
|---|---|---|---|---|---|---|---|---|
| Conjunctivitis | Gritty, not painful | Normal | No | Diffuse, worst in the fornices | Clear | Normal | Watery (viral), purulent (bacterial), stringy (allergic) | Routine |
| Subconjunctival haemorrhage | None | Normal | No | A flat, bright red, sharply bordered patch | Clear | Normal | None | Routine |
| Episcleritis | Mild ache | Normal | No | Sectoral, superficial, blanches with phenylephrine | Clear | Normal | None | Routine |
| Scleritis | Deep, boring, wakes the patient | May fall | Sometimes | Deep, violaceous, does not blanch; tender globe | Clear | Normal | None | Urgent: systemic disease behind it |
| Keratitis | Yes, foreign-body pain | Reduced | Yes | Ciliary flush | Infiltrate, epithelial defect, stains | Normal or small | Watery or purulent | Urgent: same day |
| Anterior uveitis | Deep ache | Mildly reduced | Yes, marked | Ciliary flush | Clear, or keratic precipitates | Small, irregular | None | Urgent |
| Acute angle closure | Severe, with headache and vomiting | Markedly reduced, haloes | Yes | Diffuse, with a cloudy cornea | Hazy, oedematous | Fixed, mid-dilated | None | Emergent |
Scleritis and episcleritis
Episcleritis is a sectoral, superficial redness with a mild ache, common, self-limiting, and it blanches when phenylephrine drops constrict the superficial vessels. Scleritis is a deep, violaceous redness with a boring pain that wakes the patient, a tender globe, and does not blanch; half have a systemic disease (rheumatoid arthritis, granulomatosis with polyangiitis, relapsing polychondritis) and necrotising scleritis can perforate the eye. Scleritis needs an ophthalmologist and a rheumatologist; episcleritis needs reassurance and, at most, a short course of anti-inflammatory drops.
- A verified photograph of scleritis or episcleritis is not yet in the atlas.
Do not miss
Urgent · same dayA contact lens wearer with a red painful eye has keratitis until the slit lamp says otherwise. An older patient with a red eye, headache and vomiting has angle closure until the pressure is measured. A red eye a week after eye surgery is endophthalmitis until proven otherwise. A red eye with a vesicular rash on the forehead is zoster, and the nose tells you the eye is at risk.
Go and look
Where this topic leads