Abstract
Purpose: :
To evaluate the prevalence of the refractive states and variation trend among children aged 3 to 6 years in Nantong, China.
Methods: :
A population-based cross-sectional study was conducted in Nantong City, an urban East China, in 2007. By simple random sampling, 680 children aged 3 to 6 years (170 children each age stage aged from 3 to 6 years) were randomly selected. Children were subjected to retinoscopy and optometry bilaterally after paralyzing ciliary muscles with 1% atropine ointment. The prevalence of ametropia and the average spherical equivalence by 1-year age intervals with 95% confidence interval (95% CI) were obtained and a linear regression analysis was used to study refractive states variables associated with age. A chi square test was used to test the difference of average spherical equivalence refractive error between every two different ages.
Results: :
A total of 617 (90.73%) out of 680 children participated in the survey. the prevalence of hyperopia, myopia, and emmetropia were 60.33% (95% CI, 58.36%-62.30%), 0.65% (95% CI, 0.33%-0.97%) and 39.02% (95% CI, 37.05%-40.99%) respectively. The average spherical equivalence refractive error aged 3 to 6 years by 1-year age intervals were +2.29D (95% CI, +2.20D-+2.39D), +2.03D (95% CI, +1.94D-+2.10D), +1.85D (95% CI, +1.77D-+1.93D) and +1.68D (95% CI, +1.59D-+1.78D) respectively and the differences between every two different ages had statistically significant by using chi square test (p<0.01). Linear regression analysis indicated that the mean annual decrease of refractive error was 0.2D.
Conclusions: :
Most of spherical equivalent refractive state of preschool children was slight hyperopia and emmetropia, and the refractive errors decreased year by year gradually with the increase of age.
Keywords: refraction • hyperopia