Optic disc hemorrhage (DH) may be affected by temperature and show seasonal variability throughout the year, according to findings published in the American Journal of Ophthalmology.
Investigators conducted a retrospective, observational analysis in which they reviewed stereo disc and red-free retinal nerve fiber layer photography of 13,514 patients collected at their center between 2019 and 2020. Researchers evaluated date-masked images for instances of DH, and split the 12 months into 3 categories based on average temperature (T); T<10°C, 10°C≤T<20°C, andT≥20°C.
The team determined that 3.36% of the cohort had optic DH (n=454, 63.2% women, mean age 64.9±12.8 years, mean intraocular pressure (IOP) 13.5±2.73 mm Hg). Among patients with DH, 64.3% (n=292) had normal tension glaucoma.
Regression analysis revealed that incidence of DH was negatively associated with temperature, in which every 1°C increase lowered the DH incidence ratio to 0.979 (95% CI, 0.969-0.989; P <.001). DH incidence ratio (1.532) was significantly higher for the T<10°C group (95% CI, 1.231-1.908; P <.001) compared with the T ≥20°C group.
Stratified by month and compared with January, DH was less likely in September (IRR=0.423; 95% CI, 0.262-0.683; P <.001), August (IRR=0.540; 95% CI, 0.335-0.871; P =.012), July (IRR=0.554; 95% CI, 0.365-0.842; P =.006), and May (IRR=0.537; 95% CI, 0.342-0.845; P =.007).
Researchers found that IOP was not significantly related with optic DH (R2=0.002; P =.378). However, IOP in eyes with DH was significantly higher during months in which temperatures were less than 10°C compared with months where the temperature was >20°C (mean difference, 0.71; P =0.000).
“Significant seasonal variation was confirmed when the change in the incidence rate according to the monthly-averaged temperature was analyzed or when the change in the incidence rate was analyzed by sub-grouping the seasons according to temperature,” according to the investigators. “In winter, more optic DH occurred than in summer; in other words, the lower the temperature, the higher the incidence of optic DH.”
Study limitations include a retrospective nature, single center design, a failure to account for hemorrhages that may have occurred and absorbed between visits, and failure to account for humidity, sunlight, or other seasonal factors besides temperature.
Jang M, Kim YK, Jeoung JW, Park KH. Analysis of variation in incidence of optic disc hemorrhage according to seasonal and temperature changes. Am J Ophthalmol. 2022;239:84-89. doi:10.1016/j.ajo.2022.02.007