The Incidence of Rhegmatogenous Retinal Detachment in Kumamoto, Japan between 2009 and 2011

Objective: The annual incidence of rhegmatogenous retinal detachment (RRD) in Kumamoto, Japan was previously evaluated in 1990. However, the incidence has not been evaluated during the last 20 years. The purpose of this study was to estimate the current incidence and epidemiologic characteristics of RRD in Kumamoto, Japan. Methods: The study was based on a retrospective chart review of hospital patients living in Kumamoto, Japan. All patients were treated for primary RRD by conventional surgery (pars plana vitrectomy and/or scleral buckling) at Kumamoto University Hospital or Ideta Eye Hospital between January 1, 2009, and December 31, 2011. Information on age, gender, refractive status, and history of cataract surgery was collected. Results: A total of 897 RRD patients were identified during the 3-year study period. The annual incidence of RRD was 16.5 (21.9 in males, 11.7 in females) per 100,000 people, with a peak incidence of 35.4 in the 50-59 years of age group. The incidence of RRD in males was 1.88 times (95% confidence interval, 1.56-2.29) higher than in females (P<0.0001). Prior cataract extraction was found in 14% of RRD eyes. Myopia (≤ −1 diopter [D]) was found in 54%, and high myopia (≤ −6 D) was found in 23%. The mean refraction status was −3.53 ± 3.94 D. The mean refractive status in patients younger than 50 years of age (−6.00 ± 3.33 D) was significantly higher than that in patients 50 years of age or older (−2.23 ± 3.61 D; P<0.001). The incidence of RRD in Kumamoto is expected to increase over the next 20 years in comparison to a previous study investigated in 1990. Conclusion: The annual incidence of RRD was dependent on age, gender, refraction status, and history of cataract surgery. Considering the growing elderly population, we expect that the incidence of RRD will continue to increase in Japan.