Optical differences in cases of multiple personality disorder.

Area of Science:

• Ophthalmology
• Psychiatry
• Neuroscience

Background:

• Multiple personality disorder (MPD), now known as dissociative identity disorder (DID), is characterized by the presence of two or more distinct personality states.
• Variability in sensory and perceptual functioning has been anecdotally reported in individuals with MPD.

Purpose of the Study:

• To investigate whether patients diagnosed with MPD demonstrate greater variability in visual functioning across their distinct alter personalities compared to individuals role-playing MPD.
• To quantify differences in ophthalmological measures between MPD patients and controls.

Main Methods:

• Complete ophthalmological examinations were administered to nine MPD patients and nine control subjects role-playing MPD.
• Variability of eight optical measures across four visual areas was analyzed using covariance matrices.
• Univariate analyses of variance and blind clinical significance ratings were performed.

Main Results:

• MPD subjects showed significantly greater variability in visual functioning across alter personalities than control subjects (p < .05).
• Statistically significant differences in variability were observed for visual acuity (with and without correction), visual fields, manifest refraction, and eye muscle balance.
• MPD subjects exhibited 4.5 times more clinically significant changes in optical functioning between alters than controls (mean 2.56 vs. 0.55, p < .01).

Conclusions:

• MPD is associated with significant and clinically meaningful fluctuations in visual functioning across alter personalities.
• These findings suggest a potential link between dissociative states and measurable changes in the visual system.
• Further research is warranted to explore the neurobiological underpinnings of these visual alterations in MPD.