title: Visual activity and its association with myopia stabilisation.
abstract: OBJECTIVE
  To evaluate the association between outdoor and nearwork activities at baseline and myopia stabilisation by age 15 in the Correction of Myopia Evaluation Trial (COMET).
  
  
  METHODS
  Correction of Myopia Evaluation Trial enrolled 469 children (ages: 6-11 years) with spherical equivalent myopia between -1.25 and -4.50 D, who were randomised to progressive addition or single vision lenses and followed for 5 years in their original lenses. At baseline, families recorded the child's outdoor and nearwork activities for 3 days within a week. Weekly hours spent in nearwork and outdoor activities were calculated for each participant. Refractions collected over 11 years were fit using the Gompertz function to determine each participant's myopia stabilisation age. Myopia for each child was then categorized as stable/not stable by age 15.
  
  
  RESULTS
  Half (233/469) of participants had usable baseline activity diaries and refraction data that could be fit with the Gompertz function, 59.7% (139/233) had stable myopia by age 15 and 40.3% had myopia that was not yet stable. The frequency of stable myopia was similar for the two categories (median split) of outdoor activities: 60% (71/118) for ≤9.0 hours/week(-1) and 59% (68/115) for >9.0 hours/week(-1) . 56% (64/114) of children reporting >21.0 h of baseline weekly nearwork activity had stable myopia by age 15 compared to 63% (75/119) with ≤21.0 h of near work (adjusted OR = 0.74; 95% CI: 0.43-1.29). Using baseline nearwork as a continuous variable, the multivariable odds ratio for the association between baseline nearwork hours and stabilisation by age 15 is 0.98: 95% CI: 0.96-1.00, a result trending towards significance.
  
  
  CONCLUSIONS
  While time spent in outdoor activities in childhood does not appear to be related to myopia stabilisation by age 15, less near work activity might potentially be associated with myopia stabilisation by that age.
authors.affiliation: Pennsylvania College of Optometry, Salus University, Philadelphia, USA.
authors.forename: Mitchell
authors.initials: M
authors.lastname: Scheiman
authors.forename: Qinghua
authors.initials: Q
authors.lastname: Zhang
authors.forename: Jane
authors.initials: J
authors.lastname: Gwiazda
authors.forename: Leslie
authors.initials: L
authors.lastname: Hyman
authors.forename: Elise
authors.initials: E
authors.lastname: Harb
authors.forename: Erik
authors.initials: E
authors.lastname: Weissberg
authors.forename: Katherine K
authors.initials: KK
authors.lastname: Weise
authors.forename: Lynette
authors.initials: L
authors.lastname: Dias
mesh_terms: D000293:Adolescent; D002648:Child; D005139:Eyeglasses; D005260:Female; D006801:Humans; D007899:Leisure Activities; D008019:Life Style; D008297:Male; D015999:Multivariate Analysis; D009216:Myopia / Q000209:etiology* / Q000628:therapy; D013177:Sports; D014937:Work
keywords: myopia; nearwork; outdoor activity; visual activity