@article{10.1371/journal.pone.0189016, doi = {10.1371/journal.pone.0189016}, author = {Schmidt, Felix A. AND Ruprecht, Klemens AND Connolly, Florian AND Maas, Matthew B. AND Paul, Friedemann AND Hoffmann, Jan AND Harms, Lutz AND Schreiber, Stephan J.}, journal = {PLOS ONE}, publisher = {Public Library of Science}, title = {B-mode ultrasound assessment of pupillary function: Feasibility, reliability and normal values}, year = {2017}, month = {12}, volume = {12}, url = {https://doi.org/10.1371/journal.pone.0189016}, pages = {1-10}, abstract = {Purpose To evaluate B-mode ultrasound as a novel method for the examination of pupillary function and to provide normal values for the pupillary reflex as assessed by B-mode ultrasound. Methods 100 subjects (49 female, 51 male, mean [range] age 51 [18–80 years]) with no history of ophthalmologic disease, no clinically detectable pupillary defects, and corrected visual acuity ≥ 0.8 were included in this prospective observational study. B-mode ultrasound was performed with the subjects eyes closed using an Esaote-Mylab25 system according to current guidelines for orbital insonation. A standardized light stimulus was applied. Results The mean ± standard deviation left and right pupillary diameters (PD) at rest were 4.7 ± 0.8 and 4.5 ± 0.8 mm. Following an ipsilateral light stimulus (Lstim), left and right constricted PD were 2.8 ± 0.6 and 2.7 ± 0.6 mm. Following a contralateral Lstim, left and right constricted PD were 2.7 ± 0.6 and 2.6 ± 0.5 mm. Left and right pupillary constriction time (PCT) following ipsilateral Lstim were 970 ± 261.6 and 967 ± 220 ms. Left and right PCT following a contralateral Lstim were 993.8 ± 192.6 and 963 ± 189.4 ms. Patient age was inversely correlated with PD at rest and with PD after ipsilateral and contralateral Lstim (all p<0.001), but not with PCT. Conclusions B-mode ultrasound is a simple, rapid and objective method for the quantitative assessment of pupillary function, which may prove useful in a variety of settings where eyelid retraction is impeded or an infrared pupillometry device is unavailable.}, number = {12}, }