Objective

Pupillometry is a simple, non-invasive technique that provides valuable data concerning the balance of both branches of autonomous nervous system. Heart rate recovery (HRR) after graded exercise is one of the commonly used technique which reflects autonomic activity and predicts cardiovascular events and mortality not only in cardiovascular system disorders but also in various systemic disorders. We aimed to compare pupillary autonomic functions assessed by dynamic pupillometry and cardiac autonomic functions evaluated via exercise HRR.

Methods

A total of 28 consecutive volunteer healthy subjects were enrolled. The images of both eyes are acquired and processed in real time: 30 images per second (standard) or 200 images per second (with the fast camera option). The average response to successive visual stimuli (light flashes) is quantified with the following parameters: latency and duration of contraction and dilatation; initial, minimum, maximum, and mean pupil diameter; amplitude of contraction; contraction and dilatation velocity; and percent pupil contraction (PPC).

All exercise stress tests were treadmill stress tests using the Bruce protocol and were symptom limite. HRR indices were calculated by subtracting first, second, and third minute heart rates from the maximal heart rate obtained during stress testing and designated as HRR1, HRR2, and HRR3.