PURPOSE: To evaluate the effect of treatment on the incidence of vision impairment and structural ocular complications among patients with Vogt-Koyanagi-Harada (VKH) disease. DESIGN: Retrospective cohort study. METHODS: setting: Single-center academic practice. study population: Twenty four consecutive patients with VKH disease who were referred for evaluation and treatment from November 1984 through May 2004. procedures: Information on patients with VKH disease was entered retrospectively into a database and analyzed with time-dependent techniques. main outcome measures: Incidence of visual impairment and of structural ocular complications. RESULTS: In better-seeing eyes, the frequencies of vision loss to 20/50 or worse and to 20/200 or worse at presentation were 50% and 30% , respectively. The incidence rates on follow-up examination for vision loss to 20/50 orworse and to 20/200 or worse were 9% per person-year and 7% per person-year in the better-seeing eye. Oral corticosteroid therapy was associated with a reduced risk of loss of visual acuity to the 20/200 or worse in the better-seeing eye (relative risk [RR]=0.33; P=.05). The use of immunosuppressive drug therapy was associated with a reduced risk of vision loss to the 20/50 or worse and to the 20/200 or worse thresholds in the better-seeing eye (RR=0.33; P=.05; and RR=0.08; P=.04, respectively).CONCLUSION: VKH disease may result in substantial visual impairment. The use of oral corticosteroid or immunosuppressive drug therapy may reduce the risk of vision loss during the follow-up period. PURPOSE: To evaluate the effect of treatment on the incidence of vision impairment and structural ocular complications among patients with Vogt-Koyanagi-Harada (VKH) disease. DESIGN: Retrospective cohort study. METHODS: setting: Single-center academic practice. Twenty four consecutive patients with VKH disease who were referred for evaluation and treatment from November 1984 through May 2004. procedures: Information on patients with VKH disease was entered retrospectively into a database and analyzed with time-dependent techniques. Main outcome measures: Incidence of visual impair and of structural ocular complications. RESULTS: In better-seeing eyes, the frequencies of vision loss to 20/50 or worse and to 20/200 or worse at presentation were 50% and 30%, respectively. The incidence rates on follow- up examination for vision loss to 20/50 orworse and to 20/200 or worse were 9% per person-year and 7% per person-year in the better-seeing eye. Oral corticosteroid the rapy was associated with a reduced risk of loss of visual acuity to the 20/200 or worse in the better-seeing eye (relative risk [RR] = 0.33; P = .05). The use of immunosuppressive drug therapy was associated with a reduced risk of vision loss to the 20/50 or worse and to the 20/200 or worse thresholds in the better-seeing eye (RR = 0.33; P = .05; and RR = 0.08; P = .04, respectively). CONCLUSION: VKH disease may result in substantial visual impairment. The use of oral corticosteroid or immunosuppressive drug therapy may reduce the risk of vision loss during the follow-up period.