Autonomic dysfunction detection by an automatic pupillometer as a non-invasive test in patients recovered from COVID-19

PURPOSE: To recognize dysfunctions in the autonomic nervous system (ANS) with changes in dynamic and static pupillary responses in patients who recovered from coronavirus disease-2019 (COVID-19) METHODS: One month after recovery from COVID-19, patients were subjected to eye examinations. Pupillary responses were measured using a pupillometry system. Dynamic pupil parameters (i.e., pupil contraction amplitude, pupil dilatation latency, pupil contraction latency, pupil dilatation duration, pupil dilatation velocity, pupil contraction duration, pupil contraction velocity, resting pupil diameter [PD]) and static pupil parameters (i.e., mesopic PD, scotopic PD, high photopic PD, and low photopic PD) were registered. RESULTS: Although high photopic and scotopic PDs were significantly higher in patients recovering from COVID-19 than in healthy controls (P = 0.04 and P = 0.002), no statistically significant difference was found in mesopic and low photopic PD (P = 0.19 and P = 0.41). Regarding dynamic pupillometry parameters, resting PD and pupil contraction velocity (P = 0.04 and P = 0.02, respectively) were significantly higher in patients recovering from COVID-19 than in healthy controls (P < 0.001 and P < 0.001, respectively), whereas pupil dilatation latency and pupil contraction duration were lower in these patients than in healthy controls (P = 0.01 and P = 0.008, respectively). No significant differences in pupil contraction amplitude, pupil dilatation duration, pupil contraction latency, and pupil dilatation velocity were found between the study groups (P = 0.93, P = 0.91, P = 0.42, and P = 0.48, respectively). CONCLUSION: Pupil responses, which are controlled by the ANS, were impaired in patients recovering from COVID-19. Pupillometry shows promise as a non-invasive, easy-to-apply diagnostic technology for detecting autonomic dysfunction in patients recovering from COVID-19. CLINICAL TRIAL REGISTRATION: Not applicable.