Analysis of Variation in Incidence of Optic Disc Hemorrhage According to Seasonal and Temperature Changes

PURPOSE: To investigate seasonal variation in optic disc hemorrhage (DH) by review of fundus photographs rep-resentative of 2 calendar years (2019 and 2020). DESIGN: Retrospective, observational trend study. METHODS: Patients who visited the Glaucoma Clinic of Seoul National University Hospital and underwent funus photography were included. All available stereo disc photographs and red-free retinal nerve fiber layer photographs taken between January 1, 2019 and December 31, 2020 were retrospectively reviewed. The monthly inidence rate of DH was determined by reference to the photographs. Seasonal temperature information and patients' intraocular pressure (IOP) information were ob-tained, organized, and analyzed. RESULTS: Fundus images of 13,514 eyes were re-viewed, and 454 eyes were confirmed to have DH. Pois-son regression analyses revealed that as the temperature (T) increased by 1 degrees C, the DH risk ratio was reduced to 0.979 (95% confidence interval [CI] 0.969-0.989, P < .01). The DH incidence ratio was 1.53 (95% CI 1.23-1.91, P < .01) for the T < 10 degrees C group relative to the T >= 20 degrees C group. The IOP of the patients with DH in winter was significantly higher than that measured in sum-mer. CONCLUSION: DH is affected by temperature, and as such, shows seasonal variability. This variability is be -lieved to be caused by temperature-related factors such as IOP or hematological factors. (C) 2022 Elsevier Inc. All rights reserved. (C) 2022 Elsevier Inc. All rights reserved.

Automated summary

Seasonal variation in optic disc hemorrhage (DH) was investigated through a retrospective observational study, revealing a higher incidence in winter and a significant association with temperature and intraocular pressure (IOP).