Rhegmatogenous retinal detachments. Seasonal variation and incidence

Seasonal variations in the relative incidence of rhegmatogenous retinal detachment were reported as a trend in several studies on the database of relatively limited cohort sizes. PATIENTS AND METHODS: An analysis on this topic was performed with a long-term database. A total of 3073 files of patients with rhegmatogenous retinal detachment, covering 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 for the analysis. RESULTS: The averaged seasonal incidence of rhegmatogenous detachments revealed a significant (P < 0.005) mid-summer peak (n in July = 228) and a winter trough (mean of December-January = 161; difference = 36%). Phase and curve fitting of the seasonal variations in the number of retina detachment cases was similar to the seasonal variation of the astronomic duration of the day (P < 0.001). The relation was closer compared to the average duration of light exposure per day calculated from behavioural data and the astronomic length of light phase (P < 0.0002). CONCLUSION: This long-time study revealed a close correlation of the relative seasonal incidence of retinal detachment and the seasonal variation of light hours per day. So far, this observations cannot be explained pathogenetically. Two basic hypotheses ought to be investigated further: (1) The influence of light on the generation of toxic oxygen radicals and the subsequent destruction of the vitreous and (2) possible light-induced changes in vitreoretinal adhesion.