Lateralization of pupillary light reflex parameters

Objective The aim of this study was to determine differing reactions of the left and right eyes with regard to pupillary light reflex (PLR) parameters. Methods All together 90 healthy subjects were included. In the first test series, 34 subjects were investigated on both eyes (left eye was tested first, three tests per day and one reliability test). In the second test series, 32 subjects were studied while changing the beginning side. In the last test series, 29 subjects were investigated 12 times each within 1 h (beginning side changed, without spoken advice). Infrared pupillometry was used to study pupil diameter, latency time, relative amplitude, contraction/dilation velocity, and pupil redilation time. Results The study demonstrated significant differences of PLR parameters between both eyes. In contrast to the pupil diameter of the left eye the papasympathetically-dominated right eye was not influenced by vocal instructions or by changing the beginning side. Conclusions PLR parameters might indicate functional lateralization of autonomic function in the central nervous system. High sensitivity of the procedure (arousal due to spoken advice, time of day) is advantageous for various psychophysiological investigations. Significance Differences between both eyes might point towards cortical lateralization of central autonomic function.