Acute Anterior Uveitis

Acute anterior uveitis (AAU) is sudden onset inflammation of the iris and ciliary body lasting under 3 months, and is the commonest form of uveitis (about 75 percent of cases). Usually unilateral and recurrent.

• About 50 percent are HLA-B27 positive; other associations: reactive arthritis, ankylosing spondylitis, psoriatic arthritis, inflammatory bowel disease, juvenile idiopathic arthritis (chronic rather than acute), Behçet disease, sarcoid, herpes simplex and varicella zoster, syphilis, tuberculosis, trauma, drug induced (rifabutin, bisphosphonates, sulfonamides, topical prostaglandins), and idiopathic (about 40 percent).
• Peak age 20 to 50 years, men more than women among HLA-B27-positive patients.

• Rapid onset of pain, photophobia, redness (circumcorneal ciliary flush), tearing, and blurred vision.
• Small, sluggish pupil, keratic precipitates (fine in non-granulomatous disease, mutton fat in granulomatous), anterior chamber cells and flare (grade by number of cells in a 1 x 1 mm slit beam), fibrin, hypopyon in severe disease, posterior synechiae with irregular pupil, and low or raised intraocular pressure.
• Complications: posterior synechiae, iris bombe, cataract, raised pressure, cystoid macular oedema, band keratopathy, hypotony.
• Features pointing to herpetic disease: sectoral iris atrophy, high pressure, reduced corneal sensation, scars. Features pointing to infection or masquerade: poor response to treatment, vitritis, bilateral onset.

• Clinical diagnosis with slit lamp grading of cells and flare, intraocular pressure, dilated fundus examination to exclude intermediate or posterior involvement.
• First episode of unilateral non-granulomatous anterior uveitis responding promptly to treatment does not need extensive tests. Investigate (HLA-B27, syphilis serology, chest X-ray, interferon gamma release assay, ACE, urinalysis) for recurrent, bilateral, granulomatous, severe or chronic disease.
• Back pain, joint, skin, bowel and genital questions guide systemic referral.
• Aqueous polymerase chain reaction in unilateral hypertensive uveitis with atrophy (herpes simplex, varicella zoster, cytomegalovirus).

• Topical corticosteroid: prednisolone acetate 1 percent, 1 drop every hour while awake for 2 days, then every 2 hours for 3 to 5 days, then four times daily, tapering slowly over 4 to 8 weeks (too rapid tapering causes rebound). Difluprednate 0.05 percent four times daily is an alternative.
• Cycloplegic: cyclopentolate 1 percent three times daily (or atropine 1 percent once or twice daily for severe inflammation or fibrin), phenylephrine 2.5 percent to break synechiae in the clinic.
• Severe or fibrinous disease or hypopyon: sub-conjunctival or sub-Tenon triamcinolone 20 to 40 mg, or oral prednisolone 0.5 to 1 mg/kg for 1 to 2 weeks with taper.
• Pressure: timolol 0.5 percent twice daily, dorzolamide 2 percent three times daily, brimonidine 0.2 percent; avoid prostaglandin analogues and pilocarpine in active inflammation.
• Herpetic: oral valaciclovir 1 g three times daily for 2 to 3 weeks, then 500 mg once or twice daily for prophylaxis, with topical steroid cover.
• Prevention of recurrence in frequent episodes (three or more per year, HLA-B27): sulfasalazine 500 mg daily up to 1.5 g twice daily, methotrexate 15 to 20 mg weekly, or adalimumab 40 mg every 2 weeks.
• Review at 1 week, then every 2 weeks until cell grade 0 to 0.5, and educate patients to attend early with new symptoms.