title: Predictive role of corneal Q-value differences between nasal-temporal and superior-inferior quadrants in orthokeratology lens decentration.
abstract: BACKGROUND
  To investigate the association between pretreatment corneal parameters and orthokeratology lens decentration.
  
  
  METHODS
  This retrospective study included a total of 108 eyes in 60 myopia patients, who were divided into a lens-decentration and a control group. Various pretreatment corneal parameters were analyzed by receiver operating characteristic curves (ROC curves), including corneal horizontal and vertical curvatures, diopter, corneal eccentricity (E-value), asphericity (Q-value), diameter, and astigmatism, to establish a reliable predictive model for orthokeratology lens decentration.
  
  
  RESULTS
  The temporal and inferior quadrants are preferential sides for lens decentration, which was associated with the occurrence of complications such as ghosting and corneal epithelial staining. By further analysis, we revealed lower corneal horizontal curvature and much higher corneal Q-value differences between the nasal-temporal and superior-inferior quadrants in the lens-decentration group compared to the control group (P < 0.05). ROC curve analysis showed that the sum of Q-value differences between the nasal-temporal and superior-inferior quadrants was more sensitive than any other corneal parameters in predicting lens decentration, with an area under the curve of 0.778 and a truncation point of 0.3 (P < 0.001).
  
  
  CONCLUSIONS
  The sum of pretreatment corneal Q-value differences between nasal-temporal and superior-inferior quadrants is a convenient and reliable predictor for orthokeratology lens decentration.
authors.affiliation: aDepartment of Ophthalmology, Guangdong Eye Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, China bHealth Management Center, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Li
authors.forename: Cheng
authors.initials: C
authors.lastname: Yang
authors.forename: Wenjuan
authors.initials: W
authors.lastname: Xie
authors.forename: Guanrong
authors.initials: G
authors.lastname: Zhang
authors.forename: Xue
authors.initials: X
authors.lastname: Li
authors.forename: Shujun
authors.initials: S
authors.lastname: Wang
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Yang
authors.forename: Jin
authors.initials: J
authors.lastname: Zeng
mesh_terms: D002648:Child; D003261:Contact Lenses / Q000009:adverse effects; D019781:Corneal Topography; D006801:Humans; D009216:Myopia / Q000503:physiopathology / Q000628:therapy*; D054158:Orthokeratologic Procedures / Q000009:adverse effects / Q000379:methods; D012029:Refraction, Ocular; D012189:Retrospective Studies; D014792:Visual Acuity / Q000502:physiology