ESCRS - FP11.05 - Repeatability And Agreement Of Total Corneal Astigmatism Measured In Keratoconic Eyes Using Four Current Devices

Repeatability And Agreement Of Total Corneal Astigmatism Measured In Keratoconic Eyes Using Four Current Devices

Published 2023 - 41st Congress of the ESCRS

Reference: FP11.05 | Type: Free paper | DOI: 10.82333/b6jb-7v45

Authors: Yue Feng* 1 , Aleksandar Stojanovic 2

1The Artic University of Norway,Tromsø,Norway, 2The Artic University of Norway,Tromsø,Norway;Eye department,University Hospital of North Norway,Tromsø,Norway

Purpose

To evaluate repeatability and agreement of measurements of total corneal astigmatism (TCA) in keratoconic (KC) eyes, obtained by two swept-source (SS) optical coherence tomography (OCT)-based devices (Anterion and Casia SS-1000), one SS-OCT combined with reflectometry (IOLMaster 700) and one spectral-domain (SD) OCT combined with Placido imaging (MS-39). 

Setting

Øyelegesenteret clinic in Tromsø, Norway

Methods

Three consecutive measurements were acquired with each of the four devices in 136 eyes. TCA values were transformed into power vector components (J0/J45). The acquisitions from the Anterion and the IOLMaster 700 also provided Axial length (AL) measurements. The repeatability was calculated using pooled within-subject standard deviation (Sw). The agreement between the four devices was assessed by Repeated-measures ANOVA, Bland–Altman plots, and Double-angle plots for vector difference in astigmatism

Results

The repeatability of TCA measurements showed Sw ≤ 0.23 D for cylinder magnitude, ≤ 0.14 D for J0, and ≤ 0.12 D for J45, for all four devices. There were statistically significant differences in cylinder magnitude for each pair, except when comparing IOLMaster 700 to MS-39 and Anterion to MS-39. There were statistically significant differences in J0 when comparing Anterion to MS-39 and Anterion to MS-39. The smallest mean magnitude of vector difference in astigmatism was between Anterion and Casia SS-1000 (0.55 ± 0.43 D), while the largest was between Anterion and MS-39 (1.36 ± 1.32 D). Both Anterion and IOLMaster 700 showed high repeatability in AL measurements. The difference in AL between the two was 0.015 ± 0.033 mm (p< 0.001).

Conclusions

All four devices showed good repeatability in measurements of TCA in KC eyes, but there were statistically significant variations in cylinder magnitude. Anterion and IOLMaster 700 showed good repeatability and agreement in AL measurements. Future studies are warranted to evaluate the use of the four devices in refractive procedures.