- monocular hallucination
- Also known as monocular complex hallucination. Both terms are indebted to the Greek monos (only) and the Latin oculus (eye). The term monocular hallucination was introduced in or shortly before 1936 by the Swiss neurologist Georges de Morsier (1894-1982) to denote a rare type of * complex visual hallucination that can be suppressed by the covering of one eye, especially in individuals with poor visual acuity or * blindness in the other (i.e. uncovered) eye. The suppression of these hallucinations by closure of the blind eye has also been reported. In either case the adjective monocular refers to the effect of the covering or closing of a single eye rather than the occurrence ofhallucinations in the visual field of a single eye. The German ophthalmologist Wilhelm Uhthoff (1853-1927) is commonly credited with having been the first to describe this phenomenon in 1899. Pathophysiologically, monocular hallucinations are attributed to combined retrobulbar and CNS lesions similar to those in * Charles Bonnet syndrome. Etiologically, they are associated primarily with * delirium tremens. Other conditions in which monocular hallucinations have been described include neurode-generative disorders, vascular CNS lesions, CNS trauma, neoplasms, intoxications, and epilepsy. The monocular hallucination should not be confused with the * closed-eye hallucination, which can be evoked rather than terminated by the closing ofthe eyes.Referencesffytche, D.H. (2007). Visual hallucinatory syndromes: Past, present, and future. Dialogues in Clinical Neuroscience, 9, 173-189.Ross, J., Rahman, I. (2005). Charles Bonnet Syndrome following enucleation. Eye, 20, 1394-1395.Toosy, A.T., Roberton, B.J., Jayaram, H., Plant, G.T. (2006). Monocular complex visual hallucinations and their suppression by eye closure. Eye, 20, 732-733.Uhthoff, W. (1899). Beiträge zu den Gesichtstäuschungen (Hallucinationen, Illusionen etc.) bei Erkrankungen des Sehorgans. Monatsschrift für Psychiatrie und Neurologie, 5, 241-264 & 370-379.
Dictionary of Hallucinations. J.D. Blom. 2010.