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A. R. Fedyk, C. W. Bowman; A Comparison of Corneal Power Measurement Devices to Determine Their Accuracy for Intraocular Lens Power Calculation. Invest. Ophthalmol. Vis. Sci. 2009;50(13):5084.
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© ARVO (1962-2015); The Authors (2016-present)
To compare 4 different corneal power measurement methods in determining accuracy for intraocular lens power calculation prior to cataract surgery.
We retrospectively reviewed the records of 53 eyes of 29 patients who had phacoemulsification and posterior chamber lens implantation during the past 2 years. All patients had no prior corneal surgery and no corneal pathology. Each of the patients had preoperative corneal curvature measurements taken with manual keratometry, IOL-Master, corneal topography, and Pentacam Scheimpflug camera. 2 corneal power measurements were derived from the Pentacam (simulated keratometry, BESSt formula). Following cataract surgery, using the manifest refraction obtained at 6 weeks postoperatively, the Holladay II formula was used to derive the actual corneal curvature value for each eye. These values were compared to the pre-operative corneal curvature measurements to contrast the mean absolute errors.
The mean absolute error for manual keratometry, IOL-Master, corneal topography, and Pentacam by simulated K and BESSt formula were 0.47 diopters, 0.43 diopters, 0.57 diopters, 0.63 diopters, and 0.60 diopters, respectively. 95% limits of agreement were -0.33 to 1.19 for the IOL-Master, -0.43 to 1.36 for manual keratometry, -0.44 to 1.58 for TMS, -0.23 to 1.49 for Pentacam simulated K, and -0.25 to 1.44 using the BESSt formula. Overall the statistical analysis was significant (P<0.05).
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