Box 1.

: Common causes of chronic uveitis and their distinguishing clinical features

• Anterior uveitis

• Fuchs' heterochromic cyclitis

• Uniocular; variable low grade uveitis; characteristic keratitis precipitates extending above horizontal meridian of cornea; not responsive to topical steroids; iris abnormalities; no synechiae; vitreous abnormalities

• Juvenile chronic arthritis

• Onset in childhood; bilateral; typically severe; resistant to treatment; antinuclear antibodies present, rheumatoid factor absent

• Sarcoidosis

• Unilateral or bilateral; persistent low grade inflammation; iris nodules

• Herpetic keratouveitis

• Unilateral; sector iris atrophy; corneal abnormalities; raised intraocular pressure

• Chronic idiopathic anterior uveitis

• Unilateral or bilateral; severe; resistant to treatment; idiopathic; high rate of complications

• Masquerade syndromes

• Iris infiltration; hypopyon; poor response to treatment; elevated intraocular pressure
• Intermediate uveitis

• Intermediate uveitis and pars planitis

• Variable anterior chamber reaction; occasional acute onset; vitreous cells, snowballs and snowbanks; no focal retinal or choroidal pathology; macular oedema, optic disc swelling, retinal oedema; peripheral neovascularisation
• Posterior uveitis
• Infective

• Syphilis

• Positive syphilis serology; optic disc involvement; abnormal cerebrospinal fluid; systemic signs and symptoms

• Tuberculosis

• High risk factors—HIV infection, malnutrition, immunosuppression; multifocal choroiditis; systemic illness

• Lyme disease

• History of exposure; arthropathy and cranial neuropathy; optic disc involvement; positive serology; abnormal cerebrospinal fluid

• Fungal

• High risk factors—intravenous drug misuse, central venous catheters, major illness; often delayed onset after serious systemic illness or sepsis

• Viral

• High risk factors—HIV infection, immunosuppression; cytomegalovirus retinitis, commonest in patients with AIDS; herpetic retinitis (varicella zoster virus or herpes simplex virus) commonest in other groups

• Parasitic

• Ocular toxocariasis produces unilateral chronic panuveitis associated with granulomatous mass lesion in fundus (ocular toxoplasmosis usually causes acute retinochoroiditis)
• Systemic

• Vogt Koyanagi Harada syndrome

• Neurological prodrome; profound visual loss; unusual pink swollen optic discs; multiple choroidal lesions; exudative retinal detachments; late onset poliosis and vitiligo

• Behçet's disease

• Racial predisposition; florid progressive occlusive retinitis, vasculitis, and severe panuveitis; hypopyon; mouth ulcers and genital ulcers; systemic vasculitis

• Sarcoidosis

• Unilateral or bilateral; retinal vasculitis; optic disc involvement; choroiditis
• Endogenous

• Birdshot choroidopathy

• Older age group; panuveitis; subtle punched out white non-pigmented choroidal lesions, typically nasal and posterior pole; macular oedema and disc swelling; positive HLA-A29

• Serpiginous choroidopathy

• Relentless course; media apparently not affected; slowly enlarging pigmented chorioretinal lesions; peripapillary location; acute exacerbation

• Multifocal choroiditis with panuveitis

• Multiple punched out chorioretinal scars in fundus; variable panuveitis

• Sympathetic ophthalmia

• History of trauma or surgery; bilateral panuveitis; chorioretinal lesions; serous retinal detachments
• Masquerade

• Lymphoma

• Vitreous or retinal infiltration; poor response to treatment