Predictive role of corneal Q-value differences between nasal–temporal and superior–inferior quadrants in orthokeratology lens decentration

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). CONCLUSION 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.