Refractive status and prevalence of refractive errors in suburban school-age children.
OBJECTIVE
This study investigated the distribution pattern of refractive status and prevalence of refractive errors in school-age children in Western China to determine the possible environmental factors.


METHODS
A random sampling strategy in geographically defined clusters was used to identify children aged 6-15 years in Yongchuan, a socio-economically representative area in Western China. We carried out a door-to-door survey and actual eye examinations, including visual acuity measurements, stereopsis examination, anterior segment and eyeball movements, fundus examinations, and cycloplegic retinoscopy with 1% cyclopentolate.


RESULTS
A total of 3469 children living in 2552 households were selected, and 3070 were examined. The distributions of refractive status were positively-skewed for 6-8-year-olds, and negatively-skewed for 9-12 and 13-15-year-olds. The prevalence of hyperopia (≥+2.00 D spherical equivalent [SE]), myopia (≤-0.50 D SE), and astigmatism (≥1.00 diopter of cylinder [DC]) were 3.26%, 13.75%, and 3.75%, respectively. As children's ages increased, the prevalence rate of hyperopia decreased (P<0.001) and that of myopia increased significantly (P<0.001). Children in academically challenging schools had a higher risk of myopia (P<0.001) and astigmatism (≥1.00DC, P =0.04) than those in regular schools.


CONCLUSIONS
The distribution of refractive status changes gradually from positively-skewed to negatively-skewed distributions as age increases, with 9-year-old being the critical age for the changes. Environmental factors and study intensity influence the occurrence and development of myopia.
Department of Ophthalmology, Children's Hospital, Chongqing Medical University, Chongqing, People's Republic of China.
Lian-Hong
LH
Pi
Lin
L
Chen
Qin
Q
Liu
Ning
N
Ke
Jing
J
Fang
Shu
S
Zhang
Jun
J
Xiao
Wei-Jiang
WJ
Ye
Yan
Y
Xiong
Hui
H
Shi
Zheng-Qin
ZQ
Yin
D000293:Adolescent; D017677:Age Distribution; D001251:Astigmatism / Q000175:diagnosis / Q000453:epidemiology; D002648:Child; D002681:China; D005260:Female; D006801:Humans; D008297:Male; D009216:Myopia / Q000175:diagnosis / Q000453:epidemiology; D015995:Prevalence; D012029:Refraction, Ocular / Q000502:physiology; D012030:Refractive Errors / Q000175:diagnosis / Q000453:epidemiology*