10 Oct 2026 · Case #035
Acute anterior uveitis
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Diagnosis
Acute anterior uveitis
First-line treatment
Topical corticosteroids with a cycloplegic
How the diagnosis is reached
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.
Key clinical clues
- A painful, photophobic red eye that waters without discharge and ignored antibiotic drops
- Redness in a ring at the limbus rather than spread across the conjunctiva
- A small, irregular pupil from adhesions, not the mid-dilated fixed pupil of angle closure
- Intraocular pressure normal at 12 mmHg, excluding an acute pressure rise
- Cells, flare and keratic precipitates, with HLA-B27 and sacroiliitis behind the recurrence
The case in full
Presenting complaint
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.
Background
Patient history
He has had six months of low back pain with over an hour of morning stiffness that eases once he moves about. Eighteen months ago a similar red eye settled with drops from eye casualty. He wears no contact lenses and there was no injury.
Ocular examination
Physical examination
Redness is most intense in a ring around the cornea and fades towards the outer conjunctiva. The left pupil is small and irregular. The cornea itself is clear.
| Parameter | Value | Reference |
|---|---|---|
| Visual acuity, left | 6/18Ref 6/6 | 6/6 |
| Visual acuity, right | 6/6Ref 6/6 | 6/6 |
| Intraocular pressure, left | 12 mmHgRef 10–21 | 10–21 |
| Intraocular pressure, right | 13 mmHgRef 10–21 | 10–21 |
Slit lamp examination
Physical examination
The left anterior chamber contains cells and flare. There are fine deposits on the inner surface of the cornea and adhesions tethering the iris to the lens beneath it. There is no hypopyon.
Investigations
Laboratory results
Blood and imaging results return.
| Parameter | Value | Reference |
|---|---|---|
| HLA-B27 | PositiveRef Negative | Negative |
| CRP | 18 mg/LRef <5 | <5 |
| ESR | 32 mm/hRef <20 | <20 |
| Syphilis serology | NegativeRef Negative | Negative |
| Interferon-gamma release assay | NegativeRef Negative | Negative |
| MRI sacroiliac joints | Bilateral sacroiliitisRef Normal | Normal |
The rest of the eye
Physical examination
The right eye is entirely normal. Dilated fundoscopy on the left shows a clear vitreous, a healthy optic disc and no retinal lesions. A chest radiograph is normal.