An optical viewing device is constructed having a housing with a passage extending therethrough to permit an observer to view a subject through the passageway. A pair of optical prisms are mounted within the housing and passageway, each prism designated to accommodate one of the observer's eyes. The prisms are mounted for rotation upon an axis substantially perpendicular to the observer's line of sight through the passageway. Limited inter-prism rotation is permitted to accommodate variations in the observer's left and right eyes. A filter supporting means is provided to support selected colored optical filters to be placed adjacent the opening of the housing to permit the observer to view a subject through the passageway, prisms, and optical filters.