title: Time outdoors, visual activity, and myopia progression in juvenile-onset myopes.
abstract: OBJECTIVE
  To investigate the association between myopia progression and time spent outdoors and in various visual activities.
  
  
  METHODS
  Subjects were 835 myopes (both principal meridians -0.75 diopters [D] or more myopia by cycloplegic autorefraction) in the Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) Study with both progression data and at least one measure of activity associated with a progression interval. Activity data were collected by parental survey. Average activity level (mean of the activity at the beginning and the end of a 1-year progression interval) was the primary predictor in a repeated-measures mixed model. The model controlled for age, sex, ethnicity, refractive error at the beginning of the progression interval, clinic site, and type of autorefractor used. Effects were scaled based on performing an additional 10 hours per week of an activity.
  
  
  RESULTS
  In the multivariate model, the number of hours of reading for pleasure per week was not significantly associated with annual myopia progression at an a priori level of P ≤ 0.01, nor were the other near activities, the near-work composite variable diopter-hours, or outdoor/sports activity. The magnitude of effects was clinically small. For example, the largest multivariate effect was that each additional 10 hours of reading for pleasure per week at the end of a progression interval was associated with an increase in average annual progression by -0.08 D.
  
  
  CONCLUSIONS
  Despite protective associations previously reported for time outdoors reducing the risk of myopia onset, outdoor/sports activity was not associated with less myopia progression following onset. Near work also had little meaningful effect on the rate of myopia progression.
authors.affiliation: The Ohio State University College of Optometry, Columbus, Ohio 43210, USA. ljordan@optometry.osu.edu
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Jones-Jordan
authors.forename: Loraine T
authors.initials: LT
authors.lastname: Sinnott
authors.forename: Susan A
authors.initials: SA
authors.lastname: Cotter
authors.forename: Robert N
authors.initials: RN
authors.lastname: Kleinstein
authors.forename: Ruth E
authors.initials: RE
authors.lastname: Manny
authors.forename: Donald O
authors.initials: DO
authors.lastname: Mutti
authors.forename: J Daniel
authors.initials: JD
authors.lastname: Twelker
authors.forename: Karla
authors.initials: K
authors.lastname: Zadnik
mesh_terms: D000293:Adolescent; D017668:Age of Onset; D002648:Child; D018450:Disease Progression; D005260:Female; D006306:Health Surveys; D006801:Humans; D007899:Leisure Activities; D008137:Longitudinal Studies; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D009216:Myopia / Q000453:epidemiology* / Q000503:physiopathology*; D011932:Reading; D012307:Risk Factors; D013177:Sports / Q000502:physiology*; D013997:Time Factors; D014785:Vision, Ocular / Q000502:physiology*