A 59-year-old male heart transplant recipient experienced progressive visual loss following routine cataract surgery with intraocular lens implantation. Cranial magnetic resonance (MR) imaging suggested and brain biopsy confirmed the cause to be progressive multifocal leukoencephalopathy (PML). The patient died 2 months following cataract surgery. This case illustrates that visual failure may be the initial manifestation of PML, and the ophthalmologist should be aware of this central de-myelinating disorder when dealing with immunocom-promised patients. © 1993 Raven Press, Ltd., New York.