Differences Between Keratometry And Total Keratometry Measurements In A Large Dataset Obtained With A Modern Swept Source Optical Coherence Tomography Biometer
Published 2024 - 42nd Congress of the ESCRS
Reference: FP30.03 | Type: Free paper | DOI: 10.82333/vs5w-yc97
Authors: Jascha Wendelstein* 1 , Achim Langenbucher 2 , Damien Gatinel 3 , Giacomo Savini 4 , Seth Pantanelli 5 , Matthias Bolz 6 , Theo Seiler 7 , Martin Zinkernagel 8 , Peter Hoffmann 9 , Tun Kuan Yeo 10 , Oliver Findl 11 , Kamran Riaz 12 , Ken Hoffer 13 , Guillaume Debellemanière 3
1Johannes Kepler University,Linz,Austria;Kepler University Hospital,Linz,Austria;IROC,Zürich,Switzerland, 2Saarland University,Homburg,Germany, 3Rothschild Foundation Hospital,paris,France, 4Biettei Fondation,Rome,Italy, 5Penn State,Hershey,United States, 6Kepler University Hospital,Linz,Austria;Johannes Kepler University,Linz,Austria, 7IROC,Zürich,Switzerland;Universitätsklinik Düsseldorf,Düsseldorf,Germany;Inselpital,Bern,Switzerland, 8Inselpital,Bern,Switzerland, 9Augen und Laserklinik,Castrop,Germany, 10Tan Tock Seng Hospital,Singapore,Singapore, 11Hanusch Hospital,Vienna,Austria, 12Dean A. McGee Eye Institute,Oklahoma City,United States, 13Stein Eye Institute,Los Angeles,United States
Purpose
This study aimed to explore the concept of total keratometry (TK) by analyzing extensive international datasets representing diverse ethnic backgrounds. The primary objective was to quantify the disparities between traditional keratometry (K) and TK values in normal eyes and assess their impact on intraocular lens (IOL) power calculations using various formulas.
Setting
Retrospective multicenter intra-instrument reliability analysis. Study centers were located in Europe (Austria, France, Germany, Italy, Switzerland) , Asia (Singapore), and North America (United States of America).
Methods
The study involved the analysis of biometry data collected from ten international centers across Europe, the United States, and Asia. Corneal power was expressed as equivalent power and astigmatic vector components for both K and TK values. The study assessed the influence of these differences on IOL power calculations using different formulas. The results were analyzed and plotted using Bland-Altman and double angle plots.
Results
The study encompassed a total of 116,982 measurements from 57,862 right eyes and 59,120 left eyes. The analysis revealed a high level of agreement between K and TK values, with 93.98% of eyes exhibiting an absolute difference of 0.25 D or less. Astigmatism vector differences exceeding 0.25 D and 0.50 D were observed in 39.43% and 1.08% of eyes, respectively.
Conclusions
This large-scale study underscores the similarity between mean K and TK values in healthy eyes, with rare clinical implications for IOL power calculation. Noteworthy differences were observed in astigmatism values between K and TK. Future investigations should delve into the practicality of TK values for astigmatism correction and their implications for surgical outcomes.