Does refractive error change twice as fast as corneal power in orthokeratology?

We analyzed data from 4 orthokeratology studies of refractive error change (deltaRE) and keratometer-reading change (deltaK). Instead of the reported deltaRE/deltaK ratio of 2:1, we calculated from linear-regression analysis a ratio (slope) of 2:3. The ordinate intercept of the straight line fitted to the data (N = 181 eyes) indicates that when deltaK = 0, deltaRE = 0.72. The correlation between deltaK and deltaRE is poor (+0.63). Causes and interpretations of these results are discussed.