title: Validating the accuracy of a model to predict the onset of myopia in children.
abstract: OBJECTIVE
  To assess the sensitivity and specificity of models predicting myopia onset among ethnically Chinese children.
  
  
  METHODS
  Visual acuity, height, weight, biometry (A-scan, keratometry), and refractive error were assessed at baseline and 3 years later using the same equipment and protocol in primary schools in Xiamen (China) and Singapore. A regression model predicting the onset of myopia < -0.75 diopters (D) after 3 years in either eye among Xiamen children was validated with Singapore data.
  
  
  RESULTS
  Baseline data were collected from 236 Xiamen children (mean age, 7.82 ± 0.63 years) and from 1979 predominantly Chinese children in Singapore (7.83 ± 0.84 years). Singapore children were significantly taller and heavier, and had more myopia (31.4% vs. 6.36% < -0.75 D in either eye, P < 0.001) and longer mean axial length. Three-year follow-up was available for 80.0% of Xiamen children and 83.1% in Singapore. For Xiamen, the area under the receiver-operator curve (AUC) in a model including ocular biometry, height, weight, and presenting visual acuity was 0.974 (95% confidence interval [CI], 0.945-0.997). In Singapore, the same model achieved sensitivity, specificity, and positive predictive value of 0.844, 0.650, and 0.669, with an AUC of 0.815 (95% CI, 0.791-0.839).
  
  
  CONCLUSIONS
  Accuracy in predicting myopia onset based on simple measurements may be sufficient to make targeted early intervention practical in settings such as Singapore with high myopia prevalence. Models based on cohorts with a greater prevalence of high myopia than that in Xiamen could be used to assess accuracy of models predicting more severe forms of myopia.
authors.affiliation: Joint Shantou International Eye Center, Shantou, People's Republic of China.
authors.forename: Mingzhi
authors.initials: M
authors.lastname: Zhang
authors.forename: Gus
authors.initials: G
authors.lastname: Gazzard
authors.forename: Zhifu
authors.initials: Z
authors.lastname: Fu
authors.forename: Liping
authors.initials: L
authors.lastname: Li
authors.forename: Bin
authors.initials: B
authors.lastname: Chen
authors.forename: Seang Mei
authors.initials: SM
authors.lastname: Saw
authors.forename: Nathan
authors.initials: N
authors.lastname: Congdon
mesh_terms: D017668:Age of Onset; D044466:Asian People / Q000706:statistics & numerical data*; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D015233:Models, Statistical; D009216:Myopia / Q000175:diagnosis* / Q000208:ethnology*; D011237:Predictive Value of Tests; D015995:Prevalence; D012372:ROC Curve; D012044:Regression Analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012846:Singapore / Q000453:epidemiology