title: The relationship between growth spurts and myopia in Singapore children.
abstract: OBJECTIVE
  We aimed to determine the relationship between puberty and growth spurts with peak spherical equivalent (SE) or axial length (AL) velocity in Singapore schoolchildren.
  
  
  METHODS
  In the Singapore Cohort Study of the Risk Factors for Myopia of 1779 schoolchildren, the longitudinal refractive and pubertal status of 892 boys and 887 girls from ages 6 to 14 years were assessed. The study sample included 1329 Chinese, 316 Malays, 114 Indians, and 20 children of other races. Information regarding puberty parameters, age of peak height velocity, age of menarche, and break of voice (BOV) was obtained. Peak velocity was defined as the greatest change in measurements over a period of 1 year. Tanner stage 1 for pubic hair or breast development, in boys and girls, respectively, at age 12 was categorized as "later puberty," whereas stages 2 to 5 corresponded to "earlier puberty." Refractive error was determined by cycloplegic autorefraction using the Canon RK-F5, and AL was measured using the A-scan biometry machine.
  
  
  RESULTS
  The children were examined annually, and the mean number of visits was 5.7 ± 1.3. Age of peak height velocity occurred earlier in girls than in boys (11.0 ± 1.2 vs. 12.0 ± 1.7 years, P < 0.001). Girls with earlier peak height velocity experienced peak AL velocity and peak SE velocity approximately half a year earlier than those with later puberty (mean age of 10.3 ± 1.6 vs. 10.8 ± 1.7 years, P < 0.001; and 10.0 ± 1.5 vs. 10.6 ± 1.25 years, P < 0.001, respectively). Similarly, boys who had earlier peak height velocity also achieved peak AL and peak SE velocity earlier than those who experienced later peak height velocity (mean age of 10.4 ± 1.6 vs. 11.1 ± 1.8 years, P < 0.001; and 10.1 ± 1.5 vs. 10.6 ± 1.7 years, P = 0.01). Both girls and boys who had early peak height velocity had earlier age of onset of myopia than those with later peak height velocity (9.7 ± 1.4 vs. 10.1 ± 1.5 years for girls, P = 0.04; and 9.9 ± 1.5 vs. 10.4 ± 1.6 years for boys, P = 0.03). Myopia progression, in terms of AL velocity, also occurred earlier in boys and girls with earlier peak height velocity (10.2 ± 1.5 vs. 11.0 ± 1.9 for boys, P < 0.001; and 10.2 ± 1.5 vs. 10.7 ± 1.7 for girls, P = 0.004, respectively). The associations were not significant when Tanner staging, age of menarche, or BOV was used to determine stage of puberty.
  
  
  CONCLUSIONS
  Boys and girls with earlier peak height velocity experienced earlier peak SE and AL velocity, and age of myopia onset. Thus, variations in the onset and peak progression of myopia may be associated with height spurts.
authors.affiliation: Department of Ophthalmology, Tan Tock Seng Hospital, Singapore.
authors.forename: Vivien Cherng-Hui
authors.initials: VC
authors.lastname: Yip
authors.forename: Chen-Wei
authors.initials: CW
authors.lastname: Pan
authors.forename: Xiao-Yu
authors.initials: XY
authors.lastname: Lin
authors.forename: Yung-Seng
authors.initials: YS
authors.lastname: Lee
authors.forename: Gus
authors.initials: G
authors.lastname: Gazzard
authors.forename: Tien-Yin
authors.initials: TY
authors.lastname: Wong
authors.forename: Seang-Mei
authors.initials: SM
authors.lastname: Saw
mesh_terms: D000293:Adolescent; D044466:Asian People / Q000208:ethnology; D058452:Axial Length, Eye / Q000502:physiology*; D001699:Biometry; D049628:Body Size / Q000502:physiology*; D002648:Child; D005123:Eye / Q000254:growth & development*; D005260:Female; D006801:Humans; D008297:Male; D009216:Myopia / Q000453:epidemiology / Q000503:physiopathology*; D011446:Prospective Studies; D011627:Puberty / Q000502:physiology*; D012029:Refraction, Ocular / Q000502:physiology; D012307:Risk Factors; D012846:Singapore / Q000453:epidemiology; D014792:Visual Acuity / Q000502:physiology