Seasonal variations of acute massive submacular haemorrhage associated with age-related macular degeneration.

AIMS To determine whether there is a seasonal variation in the onset of acute, massive submacular haemorrhage associated with age-related macular degeneration. METHODS Sixty eyes of 59 patients diagnosed between April 1998 and March 2005, were studied retrospectively. For each patient, the month and season of onset of the submacular haemorrhage and the mean monthly ambient temperature in Nagoya were analysed. Any history of systemic hypertension was also recorded, and the seasonal variations were also investigated in hypertensive and non-hypertensive groups. RESULTS The number of cases peaked in winter with a trough in summer, and this seasonal variation was significant (Roger's R = 12.03, p<0.01). The monthly incidence was inversely correlated with the temperature (Spearman's rank correlation coefficient r = 0.89, p<0.01). The seasonal variations were significant in the hypertensive group but not in the non-hypertensive group. CONCLUSION The considerable seasonal variations suggests that the mechanism for the haemorrhage is strongly correlated with the systemic blood pressure.