Reply: Intraocular lens power calculation after photorefractive surgery: Modified double-K method

摘要

Dr. Galvis et al. wrote that the coefficient of determination (R2) of 0.73 for the regression equation between the preoperative mean anterior K values in the 3.0 mm zone (Km) and the postoperative mean posterior corneal power in the 6.0 mm zone (K~6mm) in 72 post-LASIK eyes does not guarantee that the model fits the data sufficiently well, because a high R2 can occur in the presence of a misspecified functional form of a relationship or in the presence of outliers that distort the true relationship. However, as shown in Figure 1 in our article, the relationship between the 2 variables in our study was linear and included no outliers, meeting the major assumptions for simple linear regression analysis. Therefore, we believe the simple linear regression model is an appropriate functional form for the data and the parameter estimates are unbiased.