1. in vision, the area of the monocular visual field in which stimulation cannot be perceived because the image falls on the site of the optic disk in the eye. 2. a lack of insight or awareness—often persistent—about a specific area of one’s behavior or personality, typically because recognition of one’s true feelings and motives would be painful. In classical psychoanalysis, it is regarded as a defense against recognition of repressed impulses or memories that would threaten the patient’s ego. See scotomization.