A Comprehensive Assessment of the Precision and Agreement of Anterior Corneal Power Measurements Obtained Using 8 Different Devices

Abstract

PurposeTo comprehensively assess the precision and agreement of anterior corneal power measurements using 8 different devices.MethodsThirty-five eyes from 35 healthy subjects were included in the prospective study. In the first session, a single examiner performed on each subject randomly measurements with the RC-5000 (Tomey Corp., Japan), KR-8000 (Topcon, Japan), IOLMaster (Carl Zeiss Meditec, Germany), E300 (Medmont International, Australia), Allegro Topolyzer (Wavelight AG, Germany), Vista (EyeSys, TX), Pentacam (Oculus, Germany) and Sirius (CSO, Italy). Measurements were repeated in the second session (1 to 2 weeks later). Repeatability and reproducibility of corneal power measurements were assessed based on the intrasession and intersession within-subject standard deviation (Sw), repeatability (2.77Sw), coefficient of variation (COV), and intraclass correlation coefficient (ICC). Agreement was evaluated by 95% limits of agreement (LoA).ResultsAll devices demonstrated high repeatability and reproducibility of the keratometric values (2.77Sw<0.36D, COV<0.3%, ICC>0.98). Repeated-measures analysis of variance with Bonferroni post test showed statistically significant differences (P<0.01) among mean keratometric values of most instruments; the largest differences were observed between the EyeSys Vista and Medmont E300. Good agreement (i.e., 95%LoA within ±0.5D) was found between most instruments for flat, steep and mean keratometry, except for EyeSys and Medmont. Repeatability and reproducibility of vectors J0 and J45 was good, as the ICCs were higher than 0.9, except J45 of Medmont and Pentacam. For the 95% LoAs of J0 and J45, they were all ≤ ±0.31 among any two paired devices.ConclusionsThe 8 devices showed excellent repeatability and reproducibility. The results obtained using the RC-5000, KR-8000, IOLMaster, Allegro Topolyzer, Pentacam and Sirius were comparable, suggesting that they could be used interchangeably in most clinical settings. Caution is warranted with the measurements of the EyeSys Vista and Medmont E300, which should not be used interchangeably with other devices due to lower agreement.Trial RegistrationClinicalTrials.gov NCT01587287

Repeatability and interobserver reproducibility of a new optical biometer based on swept-source optical coherence tomography and comparison with IOLMaster

“…With low TRT (<0.31 D for repeatability and <0.16 D for reproducibility) and low CoV (not exceeding 0.26% for repeatability and 0.14% for reproducibility), we found a high precision of measurements for corneal power. It performs even better than the EyeSys (EyeSys Vision, Houston, Texas, USA) and Topolyzer (WaveLight Technologie AG, Erlangen, Germany) 7. Compared with the PCI, which measures the corneal curvature at 2.5 mm, statistically significant differences were observed, although the mean differences were small (0.09–0.13 D.) The results showed that the PCI provides slightly steeper K values than SS-OCT.…”

“…reports the repeatability and reproducibility data previously published for the latter device 7 12–18…”

“…It is designed to measure AL, ACD, LT and central corneal thickness (CCT) and is simultaneously able to measure K, pupil size and corneal diameter (CD). Since no studies have yet investigated the precision of this new biometer, the aim of the current study was to assess the intraobserver repeatability and interobserver reproducibility of the measurements using the SS-OCT instrument in normal subjects without cataract or other ocular disease, and compare these data with those derived from the standard reference, that is, PCI 6 7…”

Potec PRK-6000 Otorefraktometre, IOLMaster ve Pentacam ile Ölçülen Keratometri Değerlerinin Tekrarlanabilirliği ve Karşılaştırılması

“…Literatüre bakıldığında bu cihazların keratometrik analizdeki karşılaştırmasını yapan çeşitli yayınların bulunduğu görülmektedir. 1,7,[16][17][18] Ancak bahsedilen çalışmalar içinde Potec PRK-6000 otorefraktometresini dahil ederek IOLMaster ve Pentacam ile kıyas eden bir çalışmanın bulunmadığı görülmektedir. Bilgilerimiz ışığında literatürde ilk kez olmak üzere gerçekleştirdiğimiz bu çalışmamızda her üç cihazın da sadece korneal astigmatik değerler açısından birbiriyle uyumlu sonuçlar verdiği bulunmuştur.…”

“…[16][17][18][19] Çalışmamızda bu husus da irdelenmiş ve başta Pentacam olmak üzere her üç cihazın da oldukça tekrarlanabilir sonuçlar verdiği bulunmuştur.…”