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Enhanced keratometry for IOL power calculation after myopic LASIK: a multi-device comparison
Hung-Yuan Lin1, Chia-Chieh Hsiao2, Ya-Jung Chuang3
1Universal Eye Center, Zhong-Li, Taiwan, ROC.
Background:
To comparatively evaluate the predictive accuracy of Lenstar 900, IOL Master 700, OptiWave refractive analysis (ORA) and a modified Placido topography method in patients undergoing cataract surgery following myopic laser-assisted in situ keratomileusis (LASIK).
Methods:
A cohort of 62 post-myopic LASIK eyes from 37 patients was enrolled. Six methods were employed to estimate intraocular lens (IOL) power: Lenstar Barrett true K (BTK), Lenstar Shammas, IOL Master BTK, IOL Master BTK with total keratometry (TK), ORA and a modified Placido topography method.
Results:
Mean prediction errors and mean absolute errors were lowest to highest for the modified Placido topography method, IOL Master BTK with TK and IOL Master BTK, respectively. The IOL Master BTK, Lenstar BTK and ORA method did not significantly differ from each other. All methods outperformed Lenstar Shammas. At 2 months postoperatively, the modified Placido topography method had the highest percentages of eyes with manifest absolute prediction errors within 0.50 and 1.00 D (91.9%, 100%), followed by IOL Master BTK with TK (67.7%, 100%), IOL Master BTK (62.9%, 95.2%), ORA (54.8%, 95.2%), Lenstar BTK (53.2%, 95.2%) and Lenstar Shammas (38.7%, 67.7%).
Conclusion:
The BTK formula was highly accurate in predicting IOL power for patients undergoing cataract surgery after myopic LASIK. However, variations in keratometry values can influence outcomes. In this study, the modified Placido topography method was the most accurate, followed by IOL Master BTK with TK, IOL Master BTK, ORA, Lenstar BTK and Lenstar Shammas.
