- Rare, chronic bilateral inflammatory disorder
- Etiology: unknown
- 96% of patients have human leukocyte antigen (HLA) - A29, mostly sub-type 2
- Affects people in the fourth to sixth decades
- Affects women more than men
- Remissions and exacerbations are common
- Symptoms: floaters, gradual painless blurring of vision, dark-light adaptation impairment and peripheral photopsia
- Mild nongranulomatous iritis
- Disc edema
- Vascular sheating
- Characteristic oval, yellow-cream "birdshot" chorioretinal lesions
- May be complicated with optic atrophy, cystoid macular edema or choroidal neovascularization
- Electrophysiologic studies demonstrate a reduced electroretinogram (ERG) and normal or reduced eletrooculogram (EOG) responses
- Fluorescein angiogram:
- More placoid lesions may be seen. They remain hypofluorescent initially, but may stain in the later phases especially by the involvement of RPE.
- Diffuse leakage of dye from the retinal vessels and cystoid retinal edema may also be appreciated.
- ICG angiography reveals more lesions than fluorescein angiography which appear as hypofluorescent spots
- Observation for patients with relatively mild inflammation and asymptomatic
- Systemic steroid is indicated for more severe inflammation with decreased visual function
- Immunosuppressive agent such as cyclosporine has shown to be helpful.
- Note: due to the side effect of cyclosporine, patients should be monitored for hypertension, elevation of blood urea nitrogen and creatinine.