title: [Effects of orthokeratology lenses on the magnitude of accommodative lag and accommodativeconvergence/accommodation].
abstract: OBJECTIVE
  To evaluate the change in accommodative lag and accommodation convergence/accommodation (AC/A) after patients with myopia wear orthokeratology lenses.
  
  
  METHODS
  A total of 48 myopic subjects (a test group), who wore orthokeratology lenses regularly, and 48 myopic subjects (a control group), who wore spectacles regularly, were enrolled for this study from January 2011 to January 2013 in Optometric Center, the Forth Hospital of Changsha. Accommodative lag was measured by fused cross cylinder method, where the patients should gaze at the front optotypes 40 cm away. Gradient of the AC/A ratio was measured by Von Grafe method to check closer distance heterophoria. Accommodative lag and AC/A ratio were analyzed by statistics.
  
  
  RESULTS
  After 1-year follow-up, accommodative lag and AC/A rate in patients with low or moderate myopia in the test group was decreased in 1, 3, 6 months or 1 year compared with that in the control group (P<0.05).
  
  
  CONCLUSIONS
  Compared with spectacles, orthokeratology lenses are able to decrease accommodative lag and high AC/A rate in patients with low or moderate myopia. The relationship between accommodation and convergence is improved by orthokeratology lenses. Orthokeratology is an effective way to control myopia.
authors.affiliation: Department of Ophthalmology, The Forth Hospital of Changsha, Changsha 410000, China.
authors.forename: Qiujin
authors.initials: Q
authors.lastname: Ren
authors.affiliation: Department of Ophthalmology, The Forth Hospital of Changsha, Changsha 410000, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Yue
authors.affiliation: Department of Ophthalmology, The Forth Hospital of Changsha, Changsha 410000, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhou
mesh_terms: D000065:Accommodation, Ocular; D016022:Case-Control Studies; D003261:Contact Lenses; D005139:Eyeglasses; D006801:Humans; D009216:Myopia / Q000628:therapy*; D054158:Orthokeratologic Procedures; D013285:Strabismus