Pupil size measurements with two multifunctional devices based on different technologies and an infrared based pupillometer

Abstract Purpose To compare inter- and intra-device agreement of pupil size (PS) measurements of an aberrometer/coherence interferometer/tomographer (Pentacam AXL Wave (OCULUS)), optical coherence tomographer/placido topographer (MS-39, (CSO/Schwind)) and an infrared based pupillometer (PupilX (Albomed)). Methods In this prospective study, PS of healthy eyes was measured with Pentacam without (WO) and with glare (WG), PupilX in 0, 0.06, 0.12, 4 and 64 lx and MS-39 in 0.04, 4 and 50 lx three times each. Scotopic conditions were defined as WO and ≤ 0.12 lx, mesopic as 4 lx and photopic as WG, 50 and 64 lx. Measurements were compared per lighting condition. Results Thirty-seven eyes of 37 participants (mean age 30.8 years ± 9.1 years) were included. Pentacam WG and PupilX at 64 lx showed the lowest inter-device difference and had the only non-significant difference ( p = 0.204). The second lowest mean difference was between Pentacam WO and PupilX at 0.06 lx where significance was also not met ( p = 0.05). Pentacam WO and PupilX at 0 lx showed the highest inter-device difference ( p < 0.001). The lowest intra-device difference (IDD) for scotopic conditions was 0.19 mm (standard deviation (SD): 0.17 mm) with PupilX at 0 lx. In mesopic conditions, the lowest IDD was 0.2 mm (SD: 0.15 mm) with MS-39, in photopic conditions 0.16 mm (SD: 0.11 mm) with PupilX. Conclusion Pentacam showed close-to-acceptable agreement with PupilX in photopic conditions. In the other conditions significant differences were found, which applied for MS-39 and PupilX for all illumination levels. All three devices showed excellent intra-device repeatability for all illuminations levels.