title: Role of parental myopia in the progression of myopia and its interaction with treatment in COMET children.
abstract: OBJECTIVE
  The present study investigated the relationship between parental refractive error and myopia progression in their offspring and the interaction between parental ametropia and the effects of wearing progressive-addition (PALs) or single-vision (SVLs) lenses on the progression of myopia in children enrolled in the Correction of Myopia Evaluation Trial (COMET).
  
  
  METHODS
  The progression of myopia in a subset of COMET children (N= 232; 49% of initial group) was defined as the difference in mean spherical equivalent refraction of both eyes obtained by cycloplegic autorefraction between the baseline and 5-year visit. Parental refractions were obtained by noncycloplegic autorefraction (81%) or from recent eye examination records (19%).
  
  
  RESULTS
  The number of myopic parents (mean spherical equivalent refraction </=-0.75 D) was directly related to myopia progression among children wearing SVLs: myopia in children with no (zero) myopic parents progressed (mean +/- SE) -1.81 +/- 0.18 D and with one myopic parent, -2.04 +/- 0.13) D; these amounts were significantly less than the progression of children with two myopic parents (-2.59 +/- 0.19 D). In the PAL group, progression was not significantly related to the number of myopic parents and was -2.01 D overall. Among children with two myopic parents, progression was -2.00 D in the PAL group, significantly less than the progression of children wearing SVLs (P = 0.03). Among children with zero or one myopic parent, progression did not differ significantly between the lens groups. When the data were adjusted for covariates, the interaction between treatment effect and number of myopic parents was significant (P = 0.01). Over the 5-year study period, axial length increased 0.93 +/- 0.07 mm in children with two myopic parents wearing PALs and 1.18 +/- 0.07 mm in children with two myopic parents wearing SVLs (P = 0.01). The axial length increase in children wearing SVLs and with two myopic parents was significantly more than the 0.89 +/- 0.07 mm increase in children wearing SVLs and with zero myopic parents (P = 0.015).
  
  
  CONCLUSIONS
  Parental refraction was related to myopia progression and changes in axial length. Among COMET children with two myopic parents, myopia progression and increases in axial length were slower in the group wearing PALs than in those wearing SVLs, by a statistically significant but clinically minor amount. Because this study was ancillary to COMET and the present analyses are based on a subset of participants, conclusions must be regarded as suggestive.
authors.affiliation: New England College of Optometry, Boston, Massachusetts 02115, USA. kurtzd@neco.edu
authors.forename: Daniel
authors.initials: D
authors.lastname: Kurtz
authors.forename: Leslie
authors.initials: L
authors.lastname: Hyman
authors.forename: Jane E
authors.initials: JE
authors.lastname: Gwiazda
authors.forename: Ruth
authors.initials: R
authors.lastname: Manny
authors.forename: Li Ming
authors.initials: LM
authors.lastname: Dong
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Mitchell
authors.initials: M
authors.lastname: Scheiman
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology; D000328:Adult; D002648:Child; D016241:Child of Impaired Parents; D018450:Disease Progression; D005139:Eyeglasses; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000503:physiopathology* / Q000628:therapy*; D010290:Parents; D055656:Prescriptions; D012029:Refraction, Ocular / Q000502:physiology; D014792:Visual Acuity / Q000502:physiology