title: Nearwork-induced transient myopia and parental refractive error.
abstract: OBJECTIVE
  To investigate the relationship between parental refractive error and the nearwork-induced transient myopia (NITM) characteristics of their children.
  
  
  METHODS
  Three hundred sixty children (173 boys and 187 girls) aged 6 to 17 years were tested. Initial NITM and its decay time (DT) were assessed objectively (WAM-5500, Grand-Seiko) immediately after binocularly viewing and performing a sustained near task (5 diopters [D]) for 5 minutes, incorporating a cognitive demand with full distance refractive correction in place. The NITM was classified into three categories: low (< 0.15 D), moderate (0.15 to 0.30 D), or high (≥0.30 D), whereas its decay was classified into two categories, namely, complete or incomplete. In addition, the children were divided into three groups based on the number of myopic parents (none, one, or two) and into four groups based on the level of parental myopia (no, low, moderate, or high).
  
  
  RESULTS
  Neither paternal nor maternal refractive error was associated with either their children's initial NITM magnitude or its DT in the myopic, emmetropic, or hyperopic groups or the combined group. No significant differences (p > 0.05) in the NITM magnitude, DT, or decay time constant were found as related to the number of myopic parents or level of parental myopia. Multiple odds ratio for incomplete decay of NITM did not change significantly (p > 0.05) with either an increase in number of myopic parents or level of parental myopia.
  
  
  CONCLUSIONS
  There was no association between parental refractive error and their children's NITM characteristics. This suggests a primary environmental basis for the NITM characteristics in the children.
authors.affiliation: Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Science Key Lab, Beijing, China.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Lin
authors.forename: Balamurali
authors.initials: B
authors.lastname: Vasudevan
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Ciuffreda
authors.forename: Ning Li
authors.initials: NL
authors.lastname: Wang
authors.forename: Yi Cao
authors.initials: YC
authors.lastname: Zhang
authors.forename: Shi Song
authors.initials: SS
authors.lastname: Rong
authors.forename: Li Ya
authors.initials: LY
authors.lastname: Qiao
authors.forename: Calvin Chi Pui
authors.initials: CC
authors.lastname: Pang
authors.forename: Yuan Bo
authors.initials: YB
authors.lastname: Liang
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology*; D000293:Adolescent; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009216:Myopia / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D010290:Parents; D012029:Refraction, Ocular; D012030:Refractive Errors / Q000503:physiopathology; D012189:Retrospective Studies; D015348:Vision, Binocular / Q000502:physiology*