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Visual function in multiple personality disorder
1State College of Optometry, State University of New York, NY 10010, USA.
Background:
Multiple personality disorder (MPD) is characterized by the existence of two or more personality states that recurrently exchange control over the behavior of the individual. Numerous reports indicate physiological differences, including significant differences in ocular and visual function, across alter personality states in MPD.
Methods:
The existing literature was reviewed to provide an overview of the nature and characteristics of MPD, with emphasis on reported physiologic and ocular differences across alter personalities. In addition, a case is reported of an MPD patient seen over a 3-year period.
Results:
Physiologic differences across alter personality states in MPD include differences in dominant handedness, response to the same medication, allergic sensitivities, autonomic and endocrine function, EEG, VEP, and regional cerebral blood flow. Differences in visual function include variability in visual acuity, refraction, oculomotor status, visual field, color vision, corneal curvature, pupil size, and intraocular pressure in the various personality states of MPD subjects as compared to single personality controls.
Conclusions:
The possibility of MPDs should be considered in patients who demonstrate unusual variability in ocular and visual findings, particularly with a positive psychiatric history. The existence of visual and other physiologic differences across alter personalities in MPD offers a unique potential for the study of mind-body relationships.