Elsevier

Ophthalmology

Volume 112, Issue 10, October 2005, Pages 1676-1683
Ophthalmology

Original Article
Refractive Error in Urban and Rural Adult Chinese in Beijing

https://doi.org/10.1016/j.ophtha.2005.05.015Get rights and content

Purpose

To evaluate refractive error and its demographic associations in an urban and rural population in northern China.

Design

Epidemiological study.

Participants

The Beijing Eye Study is a population-based cohort study in northern China including 4439 subjects. Excluding pseudophakic and aphakic patients, the present study involved 4319 subjects. It was divided into a rural part (1905 [44.1%] subjects) and an urban part (2414 [55.9%] subjects). Mean age was 55.85±10.33 years (range, 40–90).

Methods

Standardized ophthalmologic examination. For statistical analysis, the spherical equivalent was converted to binary variables, and logistic regression was used to investigate the association with continuous or categorical independent variables.

Main Outcome Measure

Refractive error.

Results

Mean refractive error measured −0.33±2.22 diopters (D) (range, −20.88 to +7.88). Myopia of >−0.50 D, −1.0 D, >−6.0 D, and >−8 D, respectively, occurred in 22.9% (95% confidence interval [CI], 21.7–24.2), 16.9% (95% CI, 15.8–18.0), 2.6% (95% CI, 2.2–3.1), and 1.5% (95% CI, 1.1–1.9) of the subjects, respectively. Myopic refractive error was associated significantly with younger age (P<0.001), urban region (vs. rural region) (P<0.001), higher educational background (P<0.001), higher degree of nuclear cataract (P<0.001), decreasing uncorrected visual acuity (UCVA) (P<0.001), decreasing best-corrected visual acuity (BCVA) (P<0.001), and female gender (P<0.001). Prevalence of high myopia (myopic refractive error >−8 D) was associated with age (P<0.001), female gender (P = 0.020), urban region (P = 0.023), and lower BCVA (P<0.001). Mean anisometropia was 1.09±2.03 D (median, 0.38; range, 0–22.0). Prevalence of anisometropia of ≥1 D was associated significantly with age (P<0.001), refractive error (P<0.001), BCVA (P<0.001), and region (P<0.001). Mean astigmatic error measured 0.62±0.90 D (median, 0.25; range, 0–7.50). Astigmatism of ≥1 D was associated significantly with age (P<0.001), lower UCVA (P = 0.003), lower BCVA (P<0.001), urban area (P<0.001), and degree of cortical cataract (P = 0.027).

Conclusions

As in other population-based studies on Chinese, myopia was more prevalent in younger subjects. Myopia was associated with urban region, educational background, female gender, decreasing visual acuity, and nuclear cataract. If longitudinal studies confirm the association of refractive error with age, refractive surgery may achieve emmetropia only for a limited time.

Section snippets

Subjects and Methods

The Beijing Eye Study is a population-based prospective cohort study in northern China. It was carried out in 4 communities in the urban district of Haidian in the north of central Beijing and in 3 communities in the village area of Yufa of the Daxing district south of Beijing. The study was performed in a rural area and in an urban area because the areas differ markedly in level of education, access to medical care, mobility, frequency of hereditable diseases, and way of life. In the rural

Results

Response rates were 79.30% in the rural population and 86.95% in the urban population (Table 2). Mean monthly salary (365±351 renminbi yuan [95% CI], 376–409) vs. 1781±5820 renminbi yuan [95% CI], 1521–1854), age, and level of education were significantly lower in the rural region than in the urban region (Table 1).

Taking into account the whole study population, mean refractive error measured −0.33±2.22 D (median, 0; range, −20.88 to +7.88; 95% CI, −0.37 to −0.28) (Fig 1). The distribution

Discussion

In the present Beijing Eye Study, myopia of more than −0.5 D occurred in 21.8% of subjects, and hyperopia of more than +0.5 D was found in 20.0% of subjects (Table 3, Fig 1). High myopia of more than −8 D was present in 1.5% of subjects. Myopia was more prevalent in younger subjects and was associated with urban region, higher educational background, female gender, decreasing VA, and degree of nuclear cataract. Similar figures for the prevalence of myopia have been reported in the Shihpai Eye

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    Manuscript no. 2004-328.

    Proprietary interest: none.

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