Repeatability and agreement of biometric measurements using spectral domain anterior segment optical coherence tomography and Scheimpflug tomography in keratoconus

Li, Ye; Gokul, Akilesh; McGhee, Charles N J; Ziaei, Mohammed

doi:10.1371/journal.pone.0248659

Cited by 5 publications

(16 citation statements)

References 34 publications

(52 reference statements)

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“…22 Furthermore, the TCT of patients with KC1, 2, and 3 keratoconus measured by Casia-2 were 534.7 ± 39.9 µm, 578.1 ± 37.4 µm, and 450.7 ± 37.3 µm, respectively. 23 These results are comparable to those of our study. In contrast, the CCT measured by RTVue reported earlier in mild to moderate non-progressive keratoconus were 457.3 ± 38.9 µm and 431 ± 39.7 µm, lower than the CCTs measured by RTVue in our study, probably because the former study only included cases with stages 2-3 based on the Amsler-Krumeich classi cation criteria.…”

Section: Discussionsupporting

confidence: 91%

“…However, most previous studies on patients with keratoconus reported that FD-OCT tend to underestimate the CCT compared with Pentacam. 20,23 Patient selection may explain the discrepancy between those results and ours; previous studies included keratoconus patients with a wide range of stages, including forme fruste or KC3-4 keratoconus. Also, corneal thickness is obtained by measuring the radial distance between two concentric spheres.…”

Section: Discussioncontrasting

confidence: 61%

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A comparative study of corneal thickness measurements with the RTVue, Casia-2, and Pentacam devices in patients with mild to moderate keratoconus

Sun

Zhang

Huang

et al. 2022

Preprint

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PurposeTo explore the characteristics of the RTVue, Casia-2, and Pentacam instruments for measuring the corneal thickness in patients with mild to moderate keratoconus.MethodsWe recruited patients diagnosed with mild to moderate keratoconus at our hospital from January to March 2022; 46 eyes (46 patients) were enrolled (35 men [76.09%], 30 right eyes [65.22%], mean age 24.3 ± 6.2 years). Central corneal thickness (CCT) and thinnest corneal thickness (TCT) were measured using two optical coherence tomography (OCT) instruments (RTVue and Casia-2) and the more conventional Pentacam. Then, differences and correlations between the CCTs and TCTs based on the device and factors influencing those differences were explored.ResultsThe CCTs were 488.9 ± 41.44 µm, 488.7 ± 42.52 µm, and 489.3 ± 44.17 µm for the RTVue, Casia-2, and Pentacam, respectively. The TCT results were 465.5 ± 39.78 µm, 466.5 ± 39.39 µm, and 480.5 ± 41.27 µm for the RTVue, Casia-2, and Pentacam, respectively. The CCTs were highly consistent among the groups and correlated with one another. The TCTs measured by the RTVue and Casia-2 were thinner than the Pentacam, but all three devices were highly correlated. The RTVue and Casia-2 thinnest point location measurements significantly differed from the Pentacam (p < 0.001). Bland-Altman plots demonstrated a significant agreement between the three instruments (p < 0.001); the 95% limits of agreement were − 16.19 µm to + 17.32 µm for Pentacam and RTVue and − 15.78 µm to + 15.47 µm forPentacam and Casia-2. Multivariate analysis identified that the TCT measurement difference between the RTVue and Pentacam were related to the difference between the CCT and TCT (b = 0.532, 95% confidence interval [CI]: 0.04 to 1.024, p < 0.001), whereas the difference between the Casia-2 and Pentacam were related to the anterior radius for curvature (A) grade (b = 3.9, 95% CI: 1.753 to 6.074, p = 0.001), corneal pachymetry at the thinnest (C) grade (b = − 7.875, 95% CI: − 11.404 to − 4.346, p < 0.001), and the difference between the CCT and TCT (b = 0.425, 95% CI: 0.1 to 0.751, t = 0.012).ConclusionsThe CCTs in patients with mild to moderate keratoconus were similar among all three devices, but the TCTs and thinnest point locations were not. Furthermore, the TCT measurement differences between the OCT instruments and the Pentacam were more pronounced in keratoconus cases with a steeper anterior surface, thicker TCTs, and a larger difference between the CCT and TCT.Trial registrationRegistration number: 2021118-1. Retrospectively registered: 01 September 2021.

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Section: Discussionsupporting

confidence: 91%

Section: Discussioncontrasting

confidence: 61%

A comparative study of corneal thickness measurements with the RTVue, Casia-2, and Pentacam devices in patients with mild to moderate keratoconus

Sun

Zhang

Huang

et al. 2022

Preprint

View full text Add to dashboard Cite

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“…We used Bland–Altman plots to illustrate the agreements among the three devices for CCT measurements; an acceptable agreement was noted for all (±15 μm < LOA < ±30 μm). However, most previous studies on patients with keratoconus have reported that compared to Pentacam, FD-OCT tends to underestimate CCT [ 17 , 19 ]. Patient selection may explain the discrepancy between these previous results and our present findings; previous studies included patients with keratoconus at a wide range of stages, including forme fruste or KC3–4 keratoconus.…”

Section: Discussionmentioning

confidence: 99%

Corneal thickness measurements with the RTVue, Casia-2, and Pentacam devices in patients with mild-to-moderate keratoconus: a comparative study

et al. 2023

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Background To compare the characteristics of corneal thickness measurements among the RTVue, Casia-2, and Pentacam in patients with mild-to-moderate keratoconus. Methods We recruited 46 eyes of 46 patients diagnosed with mild-to-moderate keratoconus at our hospital between January and March 2022. The central corneal thickness (CCT) and thinnest corneal thickness (TCT) were measured using two optical coherence tomography (OCT) instruments (RTVue and Casia-2) and the more conventional Pentacam. Differences and correlations between the CCTs and TCTs, based on the device and influencing factors, were explored. Results The CCTs were highly consistent among the groups (p = 0.434) and correlated with one another (p < 0.001). The TCTs measured by OCTs were thinner than those measured by the Pentacam (p < 0.001); however, all three devices were highly correlated (p < 0.001). The thinnest point location measurements with RTVue and Casia-2 differed significantly from the measurements with the Pentacam. Bland–Altman plots demonstrated a significant agreement between Pentacam and OCTs in TCT measurement (p < 0.001); the 95% limits of agreement were − 3.1 μm to + 33.1 μm for Pentacam and RTVue and − 8.6 μm to + 36.5 μm for Pentacam and Casia-2. RTVue and Casia-2 showed no difference in corneal thickness (p = 0.633) and thinnest point location measurement (p > 0.05). Multivariate analysis identified that the TCT measurement difference between the RTVue and Pentacam was related to the difference between the CCT and TCT (b = 0.490, 95% confidence interval [CI]: 0.033 to 0.948, p = 0.036), whereas the difference between the Casia-2 and Pentacam was related to the anterior radius for curvature (A) grade (b = 3.9, 95% CI: 1.753 to 6.074, p = 0.001), corneal pachymetry at the thinnest (C) grade (b = − 7.875, 95% CI: − 11.404 to − 4.346, p < 0.001), and the difference between the CCT and TCT (b = 0.425, 95% CI: 0.1 to 0.751, p = 0.012). Conclusions CCTs in patients with mild-to-moderate keratoconus were similar among all three devices, but the TCTs and the thinnest point locations were not. Furthermore, the TCT measurement differences between the OCT devices and the Pentacam were more pronounced in keratoconus cases with a steeper anterior surface, thicker TCTs, and a larger difference between the CCT and TCT. Trial registration Number: 2021118–1. Retrospectively registered: September 01, 2021.

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“…Li et al, studied (CCT) and (TCT) in KC eyes using both Pentacam and AS-OCT measurements. Although both machines demonstrated good repeatability, there was poor agreement between different groups [ 20 ]. This contrasts with our work where a good agreement for CCT & TCT between both machine readings was demonstrated in KC patients.…”

Section: Discussionmentioning

confidence: 99%

Comparison of corneal measurements in normal and keratoconus eyes using Anterior Segment Optical Coherence Tomography (AS-OCT) and Pentacam HR topographer

et al. 2023

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Background Keratoconus (KC) is easily recognized by its unique topographic pattern, but it can be difficult to distinguish subclinical form of the disease from the normal cornea. Optovue anterior segment optical coherence tomography (AS-OCT) helps diagnose KC. Aim of the work To assess and the level of agreement of Keratometry-readings (K), Central Corneal Thickness (CCT) and Thinnest Corneal Thickness (TCT) measurements obtained by Optovue AS-OCT and Wavelight Oculyzer Pentacam HR in two groups: KC eyes and normal eyes. Patients and methods This is a prospective clinical observational study. The study included 110 eyes divided into two groups. The study group included 62 eyes with topographic evidence of KC. The control group included 48 eyes of normal subjects with no topographic evidence of KC. All of the participants underwent full cycloplegic refraction, spectacle best-corrected distance visual acuity, comprehensive slit-lamp biomicroscopy and fundoscopy. All participants underwent corneal topography by Pentacam HR and AS-OCT. Results There were highly significant differences between the studied groups as regarding BCVA, intraocular pressure and CCT measurements which were found to be lower among KC group compared to the control one. There were highly significant differences between the studied groups regarding TCT measurement detected by Pentacam HR and AS-OCT which was found to be lower among the keratoconus group compared to the control one (470.9, 455.7 versus 541.9 and 518.7 respectively). Conclusion Both Scheimpflug-based imaging and AS-OCT provide comparable readings with a good agreement regarding corneal pachymetry in keratoconus group with accurate identification of KC eyes and healthy ones. However, there was a significant difference in K readings between both devices in Keratoconus and control group.

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Repeatability and agreement of biometric measurements using spectral domain anterior segment optical coherence tomography and Scheimpflug tomography in keratoconus

Cited by 5 publications

References 34 publications

A comparative study of corneal thickness measurements with the RTVue, Casia-2, and Pentacam devices in patients with mild to moderate keratoconus

A comparative study of corneal thickness measurements with the RTVue, Casia-2, and Pentacam devices in patients with mild to moderate keratoconus

Corneal thickness measurements with the RTVue, Casia-2, and Pentacam devices in patients with mild-to-moderate keratoconus: a comparative study

Comparison of corneal measurements in normal and keratoconus eyes using Anterior Segment Optical Coherence Tomography (AS-OCT) and Pentacam HR topographer

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