hollenhorst plaque hollenhorst plaque a hollenhorst plaque is a cholesterol embolus that is seen in a blood vessel of the retina. hollenhorst plaquespecialtycardiovascular cause it is usually seen when a physician performs ophthalmoscopy, during which a plaque will appear bright, refractile, and yellow. it is caused by an embolus lodged within the retinal vessel that originated from an atheromatous plaque in a more proximal (upstream) vessel, usually the internal carotid artery. it is often an indication of a previous ischemic episode in the eye and is a sign of severe atherosclerosis. management the most important step in management is to identify and treat the originating plaque to prevent further embolization. eponym the phenomenon is named after the american ophthalmologist robert hollenhorst who first described their significance in 1961.