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To compare the accuracy of a high-resolution Scheimpflug camera-based formula (Potvin-Hill) and a spectral-domain OCT based formula to the ASCRS calculator for previous myopic LASIK eyes undergoing phacoemulsification (PE) with standard (SV) and premium (P) IOLs.
This is a retrospective nonrandomized clinical cohort study of 170 post-myopic LASIK eyes that underwent PE with PCIOL implantation. Postoperative refractive data were used to compare back-calculated optimum IOL powers (BCO) and to derive the absolute prediction error (AE). We conducted further subanalyses of the relationship between axial length, optimum power IOL, and the Potvin-Hill and OCT formulas. Eyes with corneal pathologies including keratectasia, pterygium, and Fuch's endothelial dystrophy were excluded from the study as were retinal pathologies including epiretinal membranes, age-related macular degeneration, and active diabetic retinopathy.
We implanted 72 SV PCIOLs and 98 P-IOLs (32 toric, 66 EDOF) in 170 post-myopic LASIK eyes undergoing PE. 81.6% and 91.1% of eyes fell within +/- 0.5D and +/-1.0D of target prediction refraction respectively. In descending order, BCO was most accurate for the Barrett True K formula(AE= 0.40), ASCRS Average (0.42), Masket (0.47), Modified Masket (0.53), Potvin-Hill (0.54), Haigis-L (0.54), OCT (0.62), and Shammas (0.67). When compared to the OCT and Shammas formulas, the Barrett True K, ASCRS Average, and Masket formulas demonstrated statistical significance (p<0.001).
The Barrett, ASCRS Average, and Masket formulas outperformed the Potvin-Hill and OCT power calculations although the difference was only statistically significant for the OCT power calculation comparison. The Potvin-Hill formula typically under-predicted optimum IOL power and performed best in eyes with a greater axial length.