Accuracy of corneal power measurements by a new Scheimpflug camera combined with Placido-disk corneal topography for intraocular lens power calculation in unoperated eyes

作者：Savini Giacomo^*; Barboni Piero; Carbonelli Michele; Hoffer Kenneth J

来源：Journal of Cataract and Refractive Surgery, 2012, 38(5): 787-792.

DOI：10.1016/j.jcrs.2011.11.037

PURPOSE: To assess the accuracy of the corneal power measurements with a new Scheimpflug camera combined with Placido-disk corneal topography (Sirius) (combined Scheimpflug camera-topographer) for intraocular lens (IOL) power calculation in unoperated eyes and compare the results with those by a validated corneal topographer (Keratron) (validated topographer).
SETTING: Private practice.
DESIGN: Case series.
METHODS: Consecutive patients having phacoemulsification and in-the-bag IOL implantation were studied. Intraocular lens power was calculated using the Hoffer Q, Holladay 1, and SRK/T formulas; the axial length, as measured by ultrasound immersion biometry; and 3 corneal power measurements: validated topographer simulated keratometry (K); combined Scheimpflug camera-topographer simulated K (derived from anterior corneal curvature only); combined Scheimpflug camera-topographer mean pupil power (derived from anterior and posterior corneal curvatures through ray tracing). The prediction error was calculated as the difference between the predicted refraction and the refraction measured 1 month postoperatively.
RESULTS: When the corneal power measurements from the combined Scheimpflug camera-topographer were used, the mean absolute error (MAE) ranged between 0.23 diopter (D) +/- 0.24 (SD) (simulated K and Hoffer Q formula) and 0.33 +/- 0.23 D (mean pupil power and SRK/T formula). There were no statistically significant differences between the MAE generated by the simulated Ks of the 2 devices with any of the 3 formulas.
CONCLUSION: Both corneal power measurements (simulated K and mean pupil power) provided by the new combined Scheimpflug camera-topographer were successfully entered into third-generation IOL power calculation formulas in unoperated eyes.

• 出版日期2012-5