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Klin Monbl Augenheilkd 2021; 238(11): 1213-1219
DOI: 10.1055/a-1535-1685
Klinische Studie

Reliability of Corneal, Epithelial, and Stromal Thickness Mapping for a 9-mm Zone Using Spectral-Domain Optical Coherence Tomography

Reliabilität der Pachymetriemessung von Kornea, Korneaepithel und Korneastroma mittels Spectral-Domain optische Kohärenztomografie über eine 9 mm große Zone
Daniel Krause
Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany
,
Niklas Mohr
Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany
,
Mehdi Shajari
Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany
,
Wolfgang J. Mayer 
Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany
,
Siegfried Priglinger
Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany
,
Nikolaus Luft
Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany
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Abstract

Purpose To evaluate the reliability of spectral-domain optical coherence tomography (SD-OCT; RTVue XR; Optovue, Inc., Fremont, CA, USA) for thickness mapping of the entire cornea (CT), corneal epithelium (ET). and corneal stroma (ST) over a 9-mm zone in healthy eyes. We sought to develop reference values for different age groups and elucidate potential sex- and age-dependent characteristics of corneal sublayer pachymetry maps.

Methods Three consecutive SD-OCT scans were obtained in 166 healthy right eyes (mean age = 50 ± 20 years). The thickness maps contain 25 sectors over a 9-mm diameter zone. To test measurement reliability, intraclass correlation coefficients (ICC), coefficients of variation (CoV), and within-subject standard deviations (WSSD) were calculated.

Results CT, ET, and ST ICCs ranged from 0.961 to 0.998, 0.896 to 0.945, and 0.955 to 0.998, respectively. CoV values for CT, ET, and ST ranged between 0.3 and 1.5%, 1.6 and 4.2%, and 0.4 and 1.7%, respectively. WSSD ranged from 6 to 41, 4 to 8, and 7 to 46 µm, respectively. A negative correlation was found between age and ET (p < 0.05) but not between age and ST or CT. No gender-related differences in CT, ET, or ST were detected. CoV of CT, ET, and ST measurements showed a positive correlation with age in 28, 64, and 28% of the sectors, respectively.

Conclusion SD-OCT is a rapid and noninvasive technique that provides excellent reliability for corneal sublayer thickness measurements over a 9-mm zone. The reliability of the ET measurement seems to be negatively affected by age. Peripheral CT and global ET thin with age.

Zusammenfassung

Hintergrund Die Spectral-Domain optische Kohärenztomografie (SD-OCT) hat in den letzten Jahren zunehmend auch im vorderen Augenabschnitt an Bedeutung gewonnen. Moderne SD-OCT-Geräte (RTVue XR; Optovue, Inc., Fremont, CA, USA) sind in der Lage, Pachymetriekarten der gesamten Kornea (CT), des Korneaepithels (ET) und des Korneastromas (ST) über eine 9-mm-Zone zu bestimmen. Ziele dieser Studie waren, neben einer Überprüfung der Reliabilität des Geräts, sowohl die Bestimmung von Referenzwerten für verschiedene Altersgruppen als auch die Untersuchung möglicher alters- oder geschlechtsabhängiger Merkmale der einzelnen Korneaschichten an gesunden Augen.

Methoden Es wurden 3 aufeinanderfolgende SD-OCT-Aufnahmen an 166 gesunden rechten Augen (Durchschnittsalter = 50 ± 20 Jahre) angefertigt. Die Pachymetriekarten gliedern sich in 25 Sektoren über eine Fläche mit einem Durchmesser von 9 mm. Um die Reliabilität zu messen, wurden „Intraclass Correlation Coefficients“ (ICC), „Coefficients of Variation“ (CoV) und „Within-subject Standard Deviations“ (WSSD) berechnet.

Ergebnisse Die ICCs von CT, ET und ST lagen jeweils zwischen 0,961 und 0,998, 0,896 und 0,945 sowie 0,955 und 0,998. Der CoV für CT, ET und ST lag jeweils zwischen 0,3 und 1,5%, 1,6 und 4,2% sowie 0,4 und 1,7%. Die WSSD betrug 6 – 41 µm für die CT, 4 – 8 µm für die ET und 7 – 46 µm für die ST. Die Untersuchungen ergaben eine negative Korrelation zwischen Alter und ET (p < 0,05). Für CT und ST konnte keine signifikante Korrelation gezeigt werden. Es wurden keine geschlechtsspezifischen Unterschiede für CT, ET oder ST festgestellt. Der CoV zeigte eine positive Korrelation mit dem Alter der Probanden in bis zu 64% der Sektoren.

Schlussfolgerung Die SD-OCT ist eine schnelle, nicht invasive Technik, welche für Messungen der Dicke einzelner Korneaschichten bis zu einer 9-mm-Zone eine exzellente Reliabilität bietet. Allerdings muss beachtet werden, dass die Wiederholbarkeit von Messungen des Epithels mit steigendem Alter sinkt. Ebenfalls altersabhängig wird die periphere Kornea sowie das gesamte Korneaepithel mit der Zeit dünner.

Key words

cornea - SD-OCT - reliability - anterior segment OCT

Schlüsselwörter

Kornea - SD-OCT - Vorderabschnitts-OCT - Reliabilität


Publication History

Received: 10 October 2020

Accepted: 21 June 2021

Article published online:
15 September 2021

© 2021. Thieme. All rights reserved.

Georg Thieme Verlag KG
Rüdigerstraße 14, 70469 Stuttgart, Germany

 

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