title: [The roles of AC/A ratio and other ocular motor parameters in the induction of late-onset myopia].
abstract: OBJECTIVE
  This study was to explore ocular motor parameters (accommodation and convergence) in late myopia onset and development.
  
  
  METHODS
  Eleven Emm (emmetrope), 14 S.M. (stable late-onset myopia), and 9 P.M. (progressing late-onset myopia) were include in this study. Phoria at distance and near, positive and negative relative accommodation (NRA/PRA), accommodative convergence and accommodation response were measured.
  
  
  RESULTS
  Response AC/A ratio of P.M. was higher than that of Emm or S.M. (P < 0.05); But statistically AC/A ratio was not significant difference (P > 0.05). Accommodation response (3.00 D) of Emm was higher than P.M and S.M (P < 0.05). There was significant difference in phoria in near between LOM and Emm, but none in that of distance. There was no significant difference in NRA. However, PRA of LOM was lower than that of the Emm (P < 0.05).
  
  
  CONCLUSIONS
  Ocular motor parameters are important in LOM onset and development. Response AC/A ratio (not calculated AC/A ratio) is one of key parameters among them, Response AC/A ratio is the highest in P.M, which indicates out of focus of retinal image in the developing LOM.
authors.affiliation: Department of Ophthalmology, Jinhua Central Hospital, Jinhua 321000, China. wangqcy@gmail.com
authors.forename: Qing
authors.initials: Q
authors.lastname: Wang
authors.forename: Qin-mei
authors.initials: QM
authors.lastname: Wang
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology*; D000328:Adult; D003290:Convergence, Ocular / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009216:Myopia / Q000209:etiology / Q000503:physiopathology*