Accuracy of Intraoperative Aberrometry, Barrett True-K With and Without Posterior Cornea Measurements, Shammas-PL, and Haigis-L Formulas After Myopic Refractive Surgery

PURPOSE: To assess the accuracy of intraoperative aberrometry, the Barrett True-K No History (Barrett TKNH), Barrett TKNH with posterior corneal measurements (Barrett TKNH with PC), Shammas-PL, and Haigis-L formulas in patients with cataract who had prior myopic refractive surgery. METHODS: This was a retrospective consecutive case series of patients with prior myopic refractive surgery undergoing cataract extraction. Mean absolute error (MAE) and median absolute error (MedAE) of refraction prediction were compared for each formula. Interactions of each biometry measurement were modeled for each formula to evaluate those with the most significant impact on refraction prediction. RESULTS: One hundred sixteen eyes of 79 patients were analyzed. MAE was 0.40 +/- 0.33 diopters (D) for intraoperative aberrometry and 0.42 +/- 0.31 D for the Barrett TKNH, 0.38 +/- 0.30 D for the Barrett TKNH with PC, 0.47 +/- 0.38 D for the Shammas-PL, and 0.56 +/- 0.39 D for the Haigis-L formulas. Comparisons between formulas were significant for Barrett TKNH versus Barrett TKNH with PC formulas (P = .046), Barrett TKNH with PC versus Shammas-PL formulas (P = .023), and for all comparisons with the Haigis-L formula (P < .001), and not significant for all other comparisons (P > .05). Eyes were within +/- 0.50 D of prediction 73%, 72%, 69%, 62%, and 52% of the time for intraoperative aberrometry, the Barrett TKNH with PC, Barrett TKNH, Shammas-PL, and Haigis-L formulas, respectively. Corneal asphericity (Q value) was significantly associated with prediction error for all five methods. Changes in anterior chamber depth had a significant impact on Shammas-PL prediction errors. CONCLUSIONS: Newer technology using information from the posterior cornea modestly improved outcomes when compared to established methods for intraocular lens selection in eyes that had previous laser refractive surgery for myopia.