To investigate seasonal variations in the incidence of acute primary angle closure (PAC) attack and to identify climatic factors associated with the frequency of angle closure attack. Methods

A retrospective analysis of proven cases of acute PAC attack from hospital records over a 10-year period from January 2009 to December 2018 at a tertiary hospital. The study was performed to identify and analyze sex, age on diagnosis, onset timing of symptoms. And then, compared the seasonal occurrence rates and analyzed the correlation between climatic factors and occurrence frequency. Results

A total of 227 patients of 227 eyes were diagnosed as acute PAC attack. There were 57 men and 170 women, mean age was 67.0 ± 9.1 years and the highest rate was in the 60s (38.3%). There was a statistically significant increase of acute angle closure attack incidence in women in winter ( p = 0.002). In the case of climate factors, there was a negative correlation with the average temperature and the sunshine time (r = −0.657, p = 0.030; r = −0.583, p = 0.046, respectively). There was no significant correlation with the average humidity and the rate of sunshine (r = −0.288, p = 0.364; r = 0.021, p = 0.948, respectively). Conclusions

Acute PAC glaucoma occurred more frequently in winter. Especially in women, it seems to be more affected by seasonal changes. Acute PAC attack incidence was associated with mean temperature, sum of hours of sunshine.