Prevalence And Determinants Of Refractive Errors In The Elderly Population Of The Bai Nationality Of Dali, China

Purpose:To describe the prevalence and determinants of refractive errors in the elderly people of the Bai nationality in Dali, China.Design:Population-based, cross-sectional study.Participants:persons of the Bai nationality, above 50 years old living in Dali.Methods:In a cross-sectional study with a cluster sampling method, the sampling population was selected proportional to the total population of Dali. The selected persons were invited for eye examination in a proper place. After an interview, refractive data were collected using objective and subjective refractions. Refractive error data were converted into spherical equivalent (SE), and myopia was defined as an SE worse than -0.50 Diopters (D), hyperopia worse than +0.50 D, and astigmatism was defined as cylinder power> 0.75D.Results:of the 2133 selected samples,77.8% participated in the study.63.9% were female, and36.1% were male. The mean age of the participants was 64.5±8.9 years(range,50.1 to 91.7).The prevalence of myopia in the right eye was 21.5% (95% confidence interval(CI),19.7-23.2); 23.8% in men and 20.1% in women.The rate of myopia showed an increase with age from 50 to 80, which was partially explained by the age-related increased in the prevalence of cataract. In a multiple logistic regression model, age and cataract were associated with myopia (P=0.001). The prevalence of hyperopia in the right eye was 16.0%(95% CI,14.5%-17.6%); 17.2% were women and 13.9% in men (P=0.046). The rate of hyperopia showed a⌒-shaped relationship between increasing age and the prevalence of hyperopia, the peak was among 70-75 years age group. The prevalence of astigmatism was 27.2%(95%CI,24.8%-29.5%). The prevalence of anisometropia was 8.0% (95% CI,6.9%-9.2%).Conclusions:More than one-fifth of older adult Bai people in Dali had myopia. Compared with previous reports of similarly aged, the prevalence of myopia, hyperopia, astigmatism and anisometropia was lower. Refractive errors are a major issue among the elderly and their prevalence rates vary greatly depending on age. Looks as if the refractive errors in Bai nationality are more optimistic compared with the Han nationality.