Seasonal variation in submacular hemorrhages in retinal macroaneurysms and its disappearance in age-related macular degeneration.

To investigate whether previously reported seasonal variation and winter-dominant prevalence of acute massive submacular hemorrhages (SMHs) caused by age-related macular degeneration (AMD) disappeared, and those caused by retinal microaneurysms (RMAs) emerged. The medical charts of 95 patients (95 eyes) with SMH caused by AMD and 76 patients (76 eyes) with SMH caused by RMAs in 2012–2019 were retrospectively reviewed. For each subject, the month of onset, the mean ambient temperature of that month were recorded. The monthly numbers of cases of SMHs caused by AMD from January to December were 6, 8, 4, 9, 7, 10, 9, 11, 7, 11, 3, and 10. No significant seasonal variation in the monthly incidence was identified (Roger’s R = 1.89, p = 0.39). The monthly numbers of SMHs caused by RMAs from January to December were 3, 11, 11, 8, 7, 8, 5, 5, 2, 4, 7, and 5. There was significant seasonal variation in the monthly incidence (Roger’s R = 7.67, p = 0.02). There was no significant correlation between the monthly incidence of SMHs caused by RMAs and mean ambient temperature. Our previous study conducted for cases obtained in 1998–2005 showed seasonal cyclic trend in the number of SMHs caused by AMD, with the peak in winter. However, that significant seasonal variation disappeared in 2012–2019 in the present study. Common usage of OCT devices and anti-VEGF drugs might be the reason for the lack of seasonal variation in the cases of SMH caused by AMD.