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.
Pi
Lian-Hong
LH
Department of Ophthalmology, Children's Hospital, Chongqing Medical University, Chongqing, People's Republic of China.
Chen
Lin
L
Liu
Qin
Q
Ke
Ning
N
Fang
Jing
J
Zhang
Shu
S
Xiao
Jun
J
Ye
Wei-Jiang
WJ
Xiong
Yan
Y
Shi
Hui
H
Yin
Zheng-Qin
ZQ
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*