Objective: Dynamic pupillometry (DP) is a simple, non-invasive computerized assessment of pupillary light response which provides data concerning both branches of the autonomous nervous system (ANS). Heart rate variability (HRV) analysis assess cardiac health and the ANS modulation on the heart. In this study, we aimed to evaluate the utility of DP as a predictor of cardiac autonomic activity assessed by HRV.
Patients and methods: A total of 44 consecutive healthy subjects (mean age = 35.9 ± 7.4 years, 24 males) were enrolled. Pupil diameters (R0, R1, R2 and R%): latency (Lc), amplitude (Ac), velocity (Vc) and duration of pupil contraction (Tc): latency (Ld), velocity (Vd) and duration of pupil dilatation (Td) were measured in DP. Time and frequency domain indices of HRV were obtained from 24-h ambulatory electrocardiographic monitoring.
Results: There were strong significant correlations of Vc with LF/HF (r = -0.672, p = 0.001) and a measure of HRV: RMSDD (r = 0.654, p = 0.001). R% significantly correlated with PNN50 (r = -0.432, p = 0.003) and RMSDD (r = -0.422, p = 0.004) and LF/HF (r = 0.340, p = 0.024). Vc (β = 0.647, p = 0.011) and Ac (β = 0.320, p = 0.013) were found as independent predictors of RMSSD. Vc (β = 0.578, p = 0.036) was found to be only significant predictor of PNN50. Vc (β = -0.617, p = 0.008) and R% (β = 0.309, p = 0.038) were found to be significant predictors of LF/HF.
Conclusions: Pupillary autonomic functions assessed by DP correlates with cardiac autonomic functions evaluated by HRV. Among the DP parameters analyzed, Vc was a predictor of parasympathetic indices, and R% was a predictor of sympathetic indicators of cardiac autonomic functions.