A 46-year-old previously healthy man awoke with a profound loss of vision in the left eye. Shortly thereafter, he developed a generalized skin rash. Examination revealed the findings of a combined occlusion of central retinal vein and artery in the left eye, with cutaneous lesions resembling acute erythema nodosum. The cause was proven to be early infectious (secondary) syphilis, and strongly reactive Treponema pallidum immobilization and fluorescent treponemal antibody absorption (FTA-ABS) tests were found in both peripheral blood and aqueous humor of the involved eye. A treponemal organism was found by silver stain in the aqueous humor by Prof Pierre Collart five months after the patient had received a course of 12,000,000 units of parenteral penicillin.