10 Oct 2026
Patient history
A 28-year-old man has had three days of a painful, red left eye. Bright light makes the pain worse and his vision is blurred. The eye waters but produces no discharge. Two days of chloramphenicol drops from his GP have not helped.
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Acute anterior uveitis
Topical corticosteroids with a cycloplegic
A red eye is only worth diagnosing by the pattern of the redness and the state of the pupil. Here the injection is concentrated in a ring at the limbus and fades outwards, which is ciliary rather than conjunctival and points inside the eye; conjunctivitis reddens the whole conjunctiva, spares that ring, discharges, and is gritty rather than genuinely painful, which is why the antibiotic drops did nothing. The pupil settles the rest. It is small and irregular here because inflamed iris has stuck to the lens behind it, whereas acute angle-closure glaucoma leaves a mid-dilated, oval, fixed pupil, and a normal intraocular pressure of 12 mmHg excludes that diagnosis outright. Cells and flare are protein and white cells leaking from inflamed vessels, and the fine deposits on the corneal endothelium are keratic precipitates; together they are diagnostic of anterior uveitis, and the clear vitreous, healthy disc and normal retina confine it to the front of the eye. The systemic context explains the recurrence, since HLA-B27 with inflammatory back pain and sacroiliitis is axial spondyloarthritis, the commonest association, and negative syphilis and tuberculosis screening removes the infectious causes that would contraindicate steroids. That clearance is what licenses the treatment: an intensive topical corticosteroid, prednisolone acetate hourly at first and tapered over several weeks, to shut the inflammation down. A cycloplegic such as cyclopentolate goes with it for two reasons, relieving the pain of ciliary spasm and keeping the pupil moving so that the adhesions already tethering his iris cannot set, or can be broken before they do. Pressure is monitored throughout, since the disease and the steroid can each raise it. And a second episode on a background of sacroiliitis is the argument for sending him to rheumatology rather than treating the eye again in isolation.