Reply: Assessment of PEARL-DGS Performance After Myopic Refractive Surgery

We have some concerns regarding the authors' interpretation of their findings and the general relevance of some formulas evaluated.First, the authors conclude that the EVO and Barrett True-K formulas should be the first choice for surgeons performing intraocular lens (IOL) calculations after refractive surgery.However, the mean absolute error (MAE) of the PEARL-DGS (0.62 D) was lower than that of the Barrett True-K (0.69 D) in their analyses, and the percentage of eyes in the less than 0.25, less than 0.75, less than 1.00, and greater than 1.50 diopter (D) error categories was visually higher for the PEARL-DGS than for the Barrett True-K.Although the EVO and Barrett True-K are effective and reliable postrefractive formulas, we believe the excellent performance of the PEARL-DGS in the authors' data should be more clearly highlighted.Second, the authors evaluated the performance of the PEARL-DGS "TK" by replacing the K value with TK on the online calculator.This approach cannot yield good performance due to the functioning of the formula. 2 The post-refractive version of the PEARL-DGS estimates the posterior radius from a corrected anterior radius value, and the anterior radius value used optically is also corrected.Introducing a total keratometry value skews the formula's estimates by causing double corrections.The formula referred to as "PEARL-DGS TK" in the article is not comparable to that evaluated by Anter et al. 3 The calculator's website states that we can conduct blind calculations for researchers wishing to evaluate our formula, and it is regrettable that this was not done.Finally, we believe that evaluating formulas not designed for use on eyes with a history of refractive surgery (specifically, K6 and Kane) is not relevant.The disappointing outcomes of these formulas on post-refractive eyes were predictable, and it is unfair to conclude poor performance when those formulas were not developed for this purpose.