Eye Accommodation, Personality, and Autonomic Balance.

The automatic nervous system is made up of two subsystems the parasympathetic PNS and the sympathetic SNS. The balance between these systems regulates bodily functioning during routine PNS-dominant and crisis SNS-dominant situations. It also controls visual accommodation for near PNS-dominant and far SNS-dominant focus. The balance between these physiological systems has been linked to individual differences in personality characteristics, especially introversion PNS-dominant and extraversion SNS-dominant. Since the balance mediates accommodation, the similar personality differences between near- and far-sighted individuals may be related to the more general parasympathetic-sympathetic balance rather than being related solely to the visual capability difference. The relationships among autonomic balance as measured by a battery of four physiological tests modified from Wenger and Ellington, 1943, and by a technique introduced by Porges, 1976, refractive error measured by dark focus, near and far points using a polarized vernier optometer, and introversion - extraversion Eysenck Personality Inventory introversion - extraversion scale core were investigated.