SEASONAL-VARIATIONS IN THE INCIDENCE OF R HEGMATOGENOUS RETINAL-DETACHMENT

Seasonal variations in the relative incidence of rhegmatogenous retina l detachment were reported as a trend in several studies on the databa se of relatively limited cohort sizes. Patients and methods: An analys is on this topic was performed with a long-term database. A total of 3 073 files of patients with rhegmatogenous retinal detach ment, coverin g 11 years of observation,were reviewed for this study. Patients with signs of long standing detachment or other predisposing diseases were excluded,so that a basic study population of 2314 patients remained fo r the analysis. Results: The averaged seasonal incidence of rhegmatoge nous detachments revealed a significant (P<0.005) mid-summer peak (n i n July = 228) and a winter trough (mean of December-January=161; diffe rence = 36%). Phase and curve fitting of the seasonal variations in th e number of retinal detachment cases was similar to the seasonal varia tion of the astronomic duration of the day (P<0.001). The relation was closer compared to the average duration of light exposure per day cal culated from behavioural data and the astronomic length of light phase (P<0.0002). Conclusion:This long-time study revealed a close correlati on of the relative seasonal incidence of retinal detachment and the se asonal variation of light hours per day. So far, this observations can not be explained pathogenetically. Two basic hypotheses ought to be in vestigated further:(1)The influence of I ig ht on the generation of to xic oxygen radicals and the subsequent destruction of the vitreous and (2) possible light-induced changes in vitreoretinal adhesion.