Relation of Pupil Size and retinal diseases

Purpose: The aim of this study was to evaluate differences in pupil size of subjects with diabetes mellitus, age-related macular degeneration and retinal vein occlusion at different illumination levels with a novel pupilometer. Methods: The pupil size of study participants was measured with an infrared-video pupillometer (PupilX, Albomed) at 5 different illumination levels (0, 0.5, 4, 32 and 250 lux). Measurements were performed by the same investigator. 90 images were executed during a measurement period of 3 seconds. Results: This cross-sectional study analysed 484 eyes of 242 patients with diabetes mellitus (DM), age-related macular degeneration (AMD) and retinal vein occlusion (RVO); mean age 73.8 ± 12 years, range 45-92 years. A healthy control group had 342 eyes, mean age 61.4 ± 12.5 years, range 40-87 years. There was a statistically significant smaller pupil size at the DM-group in comparison to AMD, RVO and control group at all illumination levels, except 250 lux (p=0.041, Kruskal Wallis test). There was no statistically significant difference in pupil size of RVO and AMD in comparison to the control group. Conclusion: This study provides comparative data for pupil size at different retinal diseases at different illumination conditions measured with PupilX. Pupil size in diabetic patients was significantly smaller at scotopic and mesopic illuminance conditions. Therefore we confirm using pupillometry as a noninvasive and simple tool for additive detection of autonomic dysfunction in diabetes mellitus.