Comparison of Simulated and True Keratometry Measurements Using Swept-Source Optical Coherence Tomography and Dual Scheimpflug-Placido Imaging.

Elizabeth A Urias,Rahul T Pandit,Efstathia Polychronopoulou,Marco Pellegrini

doi:10.1155/2021/5860846

Elizabeth A Urias, Rahul T Pandit + Show 2 more

Open Access

https://doi.org/10.1155/2021/5860846

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Abstract

Purpose To compare simulated and total keratometry and corneal astigmatism values between the IOLMaster 700 and Galilei G4 devices. Methods A retrospective chart review was conducted for all patients undergoing phacoemulsification by a single surgeon (RTP) from March through September 2020 and who underwent imaging with both the IOLMaster 700 and Galilei G4. Exclusion criteria were prior corneal surgery, keratectatic diseases and inability to obtain a reliable image during image acquisition. Mean, flat, and steep keratometry values as well as astigmatism magnitude were compared. Results A total of 200 eyes of 100 patients were included. Intraclass correlation coefficients (ICC) were moderate or high for all variables. Mean difference ± SD in SimK and TrueK between devices (G4-IOLM) was 0.05 ± 0.318 diopters and −1.1156 ± 0.438 diopters, respectively (p < 0.05 for both). The IOLM measured steeper TrueK value than the G4. For SimK, there was a statistically significant difference between devices only for mean keratometry (K), whereas for TrueK, there were significant differences in flat K, steep K, and mean K. Astigmatism analysis revealed a difference in mean (±SD) SimK of 0.07 (±0.57) D at 94 degrees and in mean TrueK of 0.04 (±0.85) D at 108 degrees. Conclusion Though there is overall good correlation between the IOLMaster 700 and Galilei G4 in SimK and astigmatism measurements, there is a significant difference in TrueK measurements, with the IOLM measuring steeper values by about 1.0 diopter as compared to the G4.

Highlights

To compare simulated and total keratometry and corneal astigmatism values between the IOLMaster 700 and Galilei G4 devices
Astigmatism analysis revealed a difference in mean (±standard deviation (SD)) SimK of 0.07 (±0.57) D at 94 degrees and in mean TrueK of 0.04 (±0.85) D at 108 degrees
Males comprised 49 patients, and eyes were divided between right and left eyes. e mean patient age was 66 years (SD ± 8.9; range 32–85). e mean ± SD, maximum, and minimum keratometry values for all variables measured on the IOL Master 700 (IOLM) and G4 are listed in Table 1, along with differences between devices and statistical significance

Summary

Introduction

To compare simulated and total keratometry and corneal astigmatism values between the IOLMaster 700 and Galilei G4 devices. Ough there is overall good correlation between the IOLMaster 700 and Galilei G4 in SimK and astigmatism measurements, there is a significant difference in TrueK measurements, with the IOLM measuring steeper values by about 1.0 diopter as compared to the G4. Newer technologies have allowed us to directly measure the anterior and posterior surface of the cornea to obtain the true corneal power (TrueK). High intraobserver repeatability has been demonstrated in the dual Scheimpflug analyzer for simulated total and posterior corneal power measurements and moderate repeatability for posterior corneal astigmatism [4]. E purpose of this study was to compare simulated and total keratometry and corneal astigmatism values between the IOLMaster 700 and Galilei G4 devices

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