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[Epidemiology of rhegmatogenous retinal detachment in Beijing, China].

OBJECTIVE
To investigate the incidence and epidemiological characteristics of rhegmatogenous retinal detachment (RD) in Beijing, China.


METHODS
A prospective population-based study of the incidence of rhegmatogenous RD diagnosed between October 1999 and September 2000 was performed. The study group of Epidemiology of Rhegmatogenous Retinal Detachment in Beijing, China was made-up by the Department of Health Care Epidemiology of Peking University and all 35 hospitals with conditions of diagnosis and treatment for rhegmatogenous RD in Beijing city. Standard questionnaire and diagnostic guidelines for rhegmatogenous RD were adopted. All patients diagnosed for rhegmatogenous RD the first time in this period (included in-patients and out-patients) and resided in Beijing city proper and nearby suburbs were registered and recorded. The record included the age, sex, residing district, month rhegmatogenous RD occurring, refraction, eye or eyes of illness, history of blunt trauma, history of cataract extraction, history of rhegmatogenous RD on the contra-lateral eye, etc. Cases with recurrence, retinal break without retinal detachment and without patient's compliant and subclinical RD were excluded. Exudative RD, tractional RD, secondary detachment of retina after vitrectomy or strabismus operation or excision of ocular tumor and mixed retinal detachment were also excluded.


RESULTS
A total of 526 patients were diagnosed in the city proper and the nearby suburbs. The annual incidence of rhegmatogenous RD was 7.98 per 100 000 population [95% confidence interval (CI), 7.3 - 8.7]. The incidence of blunt traumatic, aphakic or pseudophakic, and nontraumatic phakic cases being 0.93/10(5) (95% CI, 0.7 - 1.2), 0.80/10(5) (95% CI, 0.6 - 1.0), and 6.25/10(5) (95% CI, 5.7 - 6.9), respectively. The incidence of traumatic detachment for males was 1.55/10(5) (95% CI, 1.1 - 2.0), which was higher than that for females 0.30/10(5) (95% CI, 0.1 - 0.5), (Z test based on the Poisson distribution, P < 0.001). But there was no significant difference between males and females in the incidences of nontraumatic phakic detachment and aphakic detachment (Z test based on the Poisson distribution, 0.5 < P < 0.7). There were two peak incidences, one occurred in 60 - 69-age-group, and the other occurred in 20 - 29-age-group. No seasonal variations in the occurrence of retinal detachment was found (Z test based on the Poisson distribution, 0.8 < P < 0.9). There was no difference of incidence between the left and the right eye (Z test based on the Poisson distribution, P > 0.05). The proportion of bilateral detachment was 5.82% in that myopia was found in 66.5% of the patients. The proportion of high myopia in bilateral retinal detachment was greater than that of the unilateral retinal detachment (Chi-square test, 0.01 < P < 0.02).


CONCLUSIONS
The annual incidence of rhegmatogenous RD in Beijing city proper and its nearby suburbs of China between Oct 1999 and Sept 2000 was 7.98 per 10(5) population (95% CI, 7.3 - 8.7).