Scheimpflug photography keratometry readings for routine intraocular lens power calculation

PURPOSE: To prospectively evaluate keratometry (K) values obtained by Scheimpflug photography in eyes scheduled for cataract surgery, compare the results with K values obtained with an autokeratometer (automated K), and evaluate the K values in commonly used intraocular lens (IOL) power calculation formulas for routine cataract surgery. SETTING: Private clinical ophthalmology practice, Lynwood, California, USA. METHODS: The mean simulated K power (simulated K), equivalent K (equivalent K), and true net power (true net K) readings from the Pentacam Comprehensive Eye Scanner were compared with the automated K readings. Automated K, simulated K, and equivalent K values were compared in commonly used IOL power calculation formulas. RESULTS: The mean automated K value was 43.49 diopters (D) +/- 1.75 (SD) and the mean simulated K value, 43.49 +/- 2.00 D (P >.1). The mean equivalent K value was 43.78 +/- 1.97 D and exceeded the mean automated K and simulated K by 0.29 D (P >.1). The mean true net K was 42.31 +/- 2.13 D, which was 1.18 D lower than the automated K and simulated K values (P = .015). The IOL prediction mean absolute error was 0.41 +/- 0.27 D using the automated K method, 0.50 +/- 0.36 D using the simulated K method (difference 0.09 D) (P >.1), and 0.65 +/- 0.35 D using the equivalent K method (difference 0.24 D) (P <.01). CONCLUSION: The K values from Scheimpflug photography did not improve accuracy over autokeratometer values for routine IOL power calculation.