title: Validation and cost-effectiveness of a home-based screening system for amblyopia.
abstract: OBJECTIVE
  To investigate the cost-effectiveness of a novel home-based screening system for amblyopia and amblyogenic risk factors.
  
  
  METHODS
  Evaluation of diagnostic test or technology.
  
  
  METHODS
  Two thousand four hundred forty-two preschoolers 3 to 6 years of age from 10 kindergartens randomly selected from Guangzhou participated in the study in 2009.
  
  
  METHODS
  Preschoolers were assessed for amblyopia and amblyogenic risk factors by their parents using the home-based screening system and were re-evaluated by professionals who conducted a comprehensive eye examination.
  
  
  METHODS
  Sensitivity, specificity, positive predictive value, negative predictive value, and the cost-benefit of the home-based screening system were calculated by comparing the results from the home-assessed model and those from the professional evaluation.
  
  
  RESULTS
  Three thousand three hundred children were invited to participate in the study, and 2308 (1216 boys and 1092 girls) completed all of the procedures. Twenty-four amblyopes were found by professional examinations. Fifteen of these amblyopes had not been diagnosed previously, and 12 of them were detected by the home-assessment model. The sensitivity, specificity, positive predictive value, and negative predictive value were 80.0%, 94.1%, 8.2%, and 99.9%, respectively. Professional examinations cost an average of US $1131.00 per case of amblyopia detected, whereas the cost was only US $266.00 per case for the home-based method. For amblyogenic factors, 50, 87, and 96 children were classified into grade I, II, or III according to the professional examinations. The corresponding numbers in the home-based system were 23, 29, and 15, respectively. Accordingly, the true positive rates were 46.0%, 33.3%, and 15.6% for each grade.
  
  
  CONCLUSIONS
  The home-based amblyopia screening system was found to be a simple, effective, and cost-beneficial method for amblyopia screening and amblyogenic risk factors. The approach offers a practical option for developing areas with large populations.
  
  
  BACKGROUND
  The author(s) have no proprietary or commercial interest in any materials discussed in this article.
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong Province, China.
authors.forename: Weizhong
authors.initials: W
authors.lastname: Lan
authors.forename: Feng
authors.initials: F
authors.lastname: Zhao
authors.forename: Zhen
authors.initials: Z
authors.lastname: Li
authors.forename: Junwen
authors.initials: J
authors.lastname: Zeng
authors.forename: Wenyan
authors.initials: W
authors.lastname: Liu
authors.forename: Jinhua
authors.initials: J
authors.lastname: Lu
authors.forename: Dehui
authors.initials: D
authors.lastname: Zheng
authors.forename: Lixia
authors.initials: L
authors.lastname: Lin
authors.forename: Jian
authors.initials: J
authors.lastname: Ge
authors.forename: Zhikuan
authors.initials: Z
authors.lastname: Yang
mesh_terms: D000550:Amblyopia / Q000175:diagnosis* / Q000191:economics* / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D003362:Cost-Benefit Analysis; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008297:Male; D009988:Orthoptics / Q000191:economics* / Q000295:instrumentation; D011237:Predictive Value of Tests; D015995:Prevalence; D012307:Risk Factors; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires; D015351:Vision Screening / Q000191:economics* / Q000295:instrumentation