title: Comparison of Near Addition Value Prescription Methods for Myopic Children.
abstract: OBJECTIVE
  To compare personalized near addition values for myopic children that induce a reasonable phoria (Ph) (meeting Sheard's criterion) and induce a null lag of accommodation at near and to evaluate changes in these metrics after lens adaptation.
  
  
  METHODS
  Fifty-three myopic children participated in this study. Accommodative response, Ph, and fusional amplitudes (FAs) were measured at 33 cm through multiple addition lenses (0D, +1.00D, +1.50D, +2.00D, +2.50D, +3.00D). The adaptation effect on measured parameters was evaluated after 6 min of near work with each addition. The FA/Ph ratios were calculated for each addition and fitted using a rational function to obtain the optimal addition value satisfying Sheard's criterion (FA/Ph ≥ 2). Lag of accommodation change in association with addition value was assessed using linear regressions to obtain the addition values inducing a null lag.
  
  
  RESULTS
  Lag of accommodation (r = -0.987, p < 0.001) and Ph (r = -0.999, p < 0.001) decreased linearly with addition value. The 6-min adaptation induced a small but significant increase in accommodative lag and an exophoric shift (p < 0.05). Three FA/Ph patterns with respect to addition lenses were observed based on the near Ph: orthophoria/exophoria, low esophoria, and large esophoria. Addition values based on Sheard's criterion (mean ± SD, +2.16 ± 0.79D) were significantly lower than those based on null lag (+2.83 ± 0.44D, t = 19.86, p < 0.001). The FA/Ph ratio was less than 2.0 in 75.5% of subjects with additions determined through null accommodative lag. Additions determined through FA/Ph ≥ 2 induced a lag of accommodation of 0.38 ± 0.42D.
  
  
  CONCLUSIONS
  Personalized near addition values using Sheard's criterion were lower than those obtained through null lag of accommodation. These values should allow a better binocular balance especially for exophoric children.
authors.affiliation: *MD †PhD The Eye Hospital of Wenzhou Medical University (XY, JB, WL, GW, JX, HC); WMU-Essilor International Research Centre, Wenzhou, China (XY, JB, BD, WL, GW, JX, HC); and R&D Asia, Essilor International, Singapore (BD).
authors.forename: Xinping
authors.initials: X
authors.lastname: Yu
authors.forename: Jinhua
authors.initials: J
authors.lastname: Bao
authors.forename: Björn
authors.initials: B
authors.lastname: Drobe
authors.forename: Wenhui
authors.initials: W
authors.lastname: Lv
authors.forename: Ge
authors.initials: G
authors.lastname: Wu
authors.forename: Jinling
authors.initials: J
authors.lastname: Xu
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology*; D000221:Adaptation, Ocular / Q000502:physiology; D002648:Child; D005139:Eyeglasses; D005260:Female; D006801:Humans; D008297:Male; D009216:Myopia / Q000503:physiopathology / Q000628:therapy*; D055656:Prescriptions; D013285:Strabismus / Q000503:physiopathology; D014937:Work