Elevated Factor VIII-von Willebrand factor antigen levels are associated with vascular endothelial injury in several disorders, including scleroderma, Raynaud's phenomenon, polymyalgia rheumatica, and temporal arteritis. Eight patients with serpiginous choroidopathy were evaluated with the use of quantitative immunoelectrophoresis for Factor VIII-von Willebrand factor antigen. The serpiginous choroidopathy patients had a mean Factor VIII-von Willebrand factor activity of 226 +/- 47.3%, whereas a disease-free, age- and sex-matched control group had a mean activity of 107 +/- 28%. These findings are statistically significant (P greater than 0.005) and suggest that in some patients, serpiginous choroidopathy represents an occlusive vascular phenomenon that involves the choroidal circulation.