Cardiovascular autonomic rhythms in spontaneous pupil fluctuations

The aim of this paper was to investigate the relationship between spontaneous pupil diameter fluctuations and autonomic rhythms of cardiovascular variability signals. ECG, Finapres and respiration data from 10 normal subjects were recorded simultaneously to spontaneous pupil diameter fluctuations obtained from a portable infrared TV pupillometer. Power spectra of pupillary fluctuations showed in all the subjects a respiratory component with significant spectral coherence with the high frequency components of the tachogram and systogram. Moreover a discrete power distribution in the low frequency band have been identified; coherence with LF power in tachograms and systograms was significant in 6/10 subjects. It is concluded that cardiovascular autonomic rhythms can be detected in spontaneous pupil diameter fluctuations.