Key Facts

Anterior uveitis is a sight-threatening condition requiring prompt ophthalmological assessment and treatment to prevent complications including posterior synechiae, cataract, and glaucoma.

Epidemiology

• Incidence: 15-25 per 100,000 per year
• Peak age: 20-50 years
• 50% are HLA-B27 positive
• Most common cause of non-traumatic anterior uveitis in young adults

Aetiology

• Idiopathic: ~50% of cases
• HLA-B27 associated: ankylosing spondylitis, reactive arthritis, psoriatic arthritis, IBD
• Infectious: herpes simplex, herpes zoster, syphilis, TB, Lyme disease
• Sarcoidosis: bilateral granulomatous uveitis with large KPs
• Behçet's disease: recurrent uveitis + oral/genital ulcers
• Juvenile idiopathic arthritis (JIA): in children; often asymptomatic; screening required

Pathophysiology

• Inflammation of the iris and ciliary body → breakdown of blood-aqueous barrier → protein and inflammatory cells leak into anterior chamber (flare and cells)
• Fibrin deposition can cause posterior synechiae (iris adheres to lens capsule)
• Chronic inflammation → secondary glaucoma (trabecular meshwork obstruction) and cataract (steroid-related or inflammatory)

Symptoms

• Unilateral painful red eye (deep aching)
• Photophobia (often consensual — light in other eye causes pain)
• Blurred vision
• Lacrimation
• Small pupil (miosis) — due to sphincter spasm

Signs

• Ciliary flush (circumcorneal injection)
• Cells and flare in anterior chamber (slit lamp)
• Keratic precipitates (KPs): deposits on corneal endothelium
  • Small KPs: non-granulomatous (HLA-B27)
  • Large "mutton-fat" KPs: granulomatous (sarcoid, TB)
• Posterior synechiae: irregular pupil
• Hypopyon: layered white cells in anterior chamber (severe; Behçet's, HLA-B27)

Red Flags

• Bilateral uveitis (systemic cause likely)
• Recurrent episodes
• Granulomatous KPs (sarcoid, TB)
• Hypopyon (Behçet's, severe)
• In children (JIA — may be asymptomatic)
• Vitritis or retinal involvement (posterior uveitis — different management)

Bedside

• Visual acuity
• Slit lamp examination (cells, flare, KPs, synechiae)
• IOP measurement (may be low in acute uveitis; raised in chronic or steroid-induced)
• Fundoscopy (exclude posterior segment involvement)

Bloods

• First episode, unilateral, non-granulomatous: often no investigations needed
• Recurrent, bilateral, granulomatous, or atypical:
  • HLA-B27
  • ACE level, serum calcium (sarcoidosis)
  • Syphilis serology (VDRL/TPHA)
  • FBC, ESR/CRP
  • Quantiferon/T-SPOT (tuberculosis)
  • ANA (JIA in children)

Imaging

• CXR: sarcoidosis (bilateral hilar lymphadenopathy), TB
• Sacroiliac joint X-ray/MRI: if ankylosing spondylitis suspected

Special Tests

• OCT: macular oedema assessment
• Fluorescein angiography: if posterior involvement suspected

Non-pharmacological

• Sunglasses for photophobia
• Patient education about recurrence and when to seek help

Pharmacological

• Topical corticosteroid (mainstay):
  • Dexamethasone 0.1% drops: initially 1-2 hourly then taper over 6-8 weeks
  • Prednisolone 1% drops: alternative
  • Taper slowly (too rapid withdrawal → rebound)
• Cycloplegic (prevents posterior synechiae + provides pain relief):
  • Cyclopentolate 1% TDS (or atropine 1% BD for severe cases)
• IOP management: if raised, topical timolol 0.5% BD or dorzolamide; avoid prostaglandin analogues (may worsen uveitis)
• Systemic treatment (for recurrent/severe/bilateral):
  • Consider systemic immunosuppression: methotrexate, azathioprine, mycophenolate
  • Biologic agents: adalimumab (anti-TNFα) — NICE approved for non-infectious uveitis (VISUAL trials)

Surgical/Interventional

• Cataract surgery: for steroid-induced or inflammatory cataract
• Intravitreal steroid implant (dexamethasone — Ozurdex): for chronic/recurrent uveitis

Referral Criteria

• All suspected anterior uveitis: urgent ophthalmology referral (same day or next day)
• Recurrent/bilateral/granulomatous: investigate for systemic cause
• Children with JIA: routine ophthalmology screening (every 3-6 months)

• Good visual prognosis with prompt treatment in most cases
• Recurrence: ~50% (higher in HLA-B27+)
• Complications: posterior synechiae (20%), glaucoma (10-20%), cataract (chronic/steroid-induced), cystoid macular oedema
• JIA-associated uveitis: can be insidious; screening is essential to prevent sight loss
• HLA-B27+ anterior uveitis: typically acute, unilateral, alternating, good response to topical steroids

Uveitis Classification

HLA-B27 Associated Conditions