Agreement of Corneal Diameter Measurements Obtained by a Swept-source Biometer and a Scheimpflug-based Topographer

Salouti, Ramin; Nowroozzadeh, Mohammad Hossein; Tajbakhsh, Zahra; Bagheri, Mansoureh; Ghoreyshi, Maryam; Azizzadeh, Monir; Razeghinejad, Mohammad Reza

doi:10.1097/ico.0000000000001300

Cited by 23 publications

(21 citation statements)

References 14 publications

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“…The agreement between the measurements of the two devices was not clinically acceptable (95% LoA of −0.088 and −0.545 mm). Our data are in accordance with two previous studies 30 , 31 which concluded that the IOLMaster 700 overestimates the WTW distance compared with the Pentacam device in healthy corneas. This finding was expected because keratoconus does not affect the corneal diameter.…”

Section: Discussionsupporting

confidence: 93%

Agreement in anterior segment measurements between swept-source and Scheimpflug-based optical biometries in keratoconic eyes: a pilot study

et al. 2022

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Background: Cataract surgery in keratoconic patients is challenging because of the corneal distortion, which can lead to inaccurate keratometry readings. This study is a comparison of the accuracy of keratometry readings by two types of devices in a tertiary hospital. Purpose: To evaluate the comparability of corneal power measurements, anterior chamber depth (ACD), and white-to-white (WTW) distance between Scheimpflug-based tomography (Pentacam AXL; OCULUS GmbH, Wetzlar, Germany) and swept-source optical biometry (IOLMaster 700; Carl Zeiss Meditec AG, Jena, Germany) in patients with keratoconus. Methods: This pilot, prospective, interinstrument reliability study included 30 keratoconic eyes of 15 individuals who had not undergone any kind of corneal surgery. Standard K and total refractive power (TK®) of the flattest and steepest axes of the IOLMaster 700 were compared with the standard keratometry (SimK), true net power (TNP), equivalent keratometer readings (EKR), and total corneal refractive power (TCRP) of the Pentacam. The Bland–Altman analysis was used to evaluate the agreement between the measurements of both devices. The paired-samples t-test and the Wilcoxon signed-rank test were performed to compare the mean values of the variables obtained with the devices. Results: The K1 value of the IOLMaster 700 was significantly higher from EKR K1 along the 3-mm (mean difference: 0.79 diopters, p = 0.01), 4-mm (mean difference: 1.01 D, p = 0.01), and 4.5-mm zones (mean difference: 1.20 D, p = 0.01) and TNP K1 along the 3-mm (mean difference: 0.88 D, p < 0.001) and 4-mm zones (mean difference: 0.97 D, p < 0.001). The TK1 value was significantly higher from EKR K1 along the 2-mm (mean difference: 0.42 D, p = 0.04), 3-mm (mean difference: 0.83 D, p = 0.003), 4-mm (mean difference: 1.05 D, p = 0.004), and 4.5-mm zones (mean difference: 1.24 D, p = 0.005) and TNP K1 along the 3-mm (mean difference: 0.92 D, p < 0.001) and 4-mm zones (mean difference: 1.01 D, p < 0.001). The K2 value of the IOLMaster 700 was significantly higher from TK2 (mean difference: 0.11 D, p = 0.04) and all the corresponding variables of the Pentacam device. The TK2 value was significantly higher from all the corresponding variables of the Pentacam device. The Pentacam also yielded significantly lower values for the WTW distance (mean difference: 0.31 mm, p < 0.001) and no significant difference in terms of ACD values ( p = 0.9). Conclusion: The IOLMaster measured significantly greater keratometry readings in the steep axis for all the variables studied. The keratometry and WTW measurements of the investigated devices cannot be used interchangeably in keratoconus.

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Section: Discussionsupporting

confidence: 93%

Agreement in anterior segment measurements between swept-source and Scheimpflug-based optical biometries in keratoconic eyes: a pilot study

et al. 2022

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“…Only one study compared two of the instruments we have analyzed: the IOLMaster 700 and the Pentacam HR [12]. In fact, there are no studies comparing WTW measured with the Anterior SS-OCT and the Cassini.…”

Section: Discussionmentioning

confidence: 99%

“…In fact, there are no studies comparing WTW measured with the Anterior SS-OCT and the Cassini. This study, carried out by Salouti et al [12], evaluated the agreement between the measurements obtained in 100 patients using the IOLMaster 700 and the Pentacam HR. They reported mean values of 11.72 ± 0.45 mm and 11.41 ± 0.42 mm for the IOLMaster 700 and Pentacam HR, respectively.…”

Section: Discussionmentioning

confidence: 99%

“…It has been published several studies analyzing the agreement among instruments based on these techniques to measure WTW. These studies have analyzed the interchangeability of OCT devices and Scheimpflug cameras [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. New devices in the market and the possibility to use them to measure this distance make interesting their analysis to ascertain if there are differences between them.…”

Section: Introductionmentioning

confidence: 99%

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Agreement of white-to-white measurements with swept-source OCT, Scheimpflug and color LED devices

et al. 2020

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Purpose To assess the interchangeability of different devices for measuring white-to-white (WTW) distance. Methods WTW distance was measured in 53 eyes of 53 patients using Anterion swept-source optical coherence topographer (SS-OCT), IOLMaster 700 SS-OCT, Pentacam HR Scheimpflug and Cassini color LED. Statistical analysis was done by means of the Friedman test and the post hoc Tukey test. The Bland-Altman analysis was applied to carry out pairwise comparisons with the average difference, 95% confidence interval of the average difference and limits of agreement 95% (LoA). Results WTW values obtained by the Anterion, IOLMaster 700, Pentacam HR and Cassini were: 11.84 ± 0.41 mm, 11.96 ± 0.41 mm, 11.68 ± 0.38 mm and 12.65 ± 0.52 mm, respectively. Statistically significant differences were found in all pairwise comparison (p \ 0.001). The lowest mean difference was found between the Anterion and IOLMaster 700 (-0.11 mm) and the highest between the Pentacam HR and Cassini (-0.96 mm). The widest LoA ranges were those that compared any device with the Cassini. LoA ranges when the other three devices were compared among them were similar: Anterion versus IOLMaster 700, Anterion versus Pentacam HR and IOLMaster versus Pentacam HR (about 0.2 mm). Conclusions Our results show that there were statistically significant differences in WTW measurement among the four devices, but under a clinical point of view, we believe that Anterion and IOLMaster 700 may be considered interchangeable and so Anterion and Pentacam HR, however, IOLMaster 700 and Pentacam HR may not and neither is Cassini with any of the other three devices.

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“…The high precision was similar to those published by Lattimore et al and Shajari et al ( 39 ). However, Salouti et al ( 40 ) showed poor agreement for CD measurements between the SS-OCT optical biometer (IOLMaster 700) and the same rotating Scheimpflug camera (95% LoA, −0.17 and 0.78 mm). These results suggest that the accuracy of CD measurements depends on the method that each device uses to define the limbus and the quality of the anterior segment images that are generated.…”

Section: Discussionmentioning

confidence: 99%

Comparison of a New Optical Biometer That Combines Scheimpflug Imaging With Partial Coherence Interferometry With That of an Optical Biometer Based on Swept-Source Optical Coherence Tomography and Placido-Disk Topography

et al. 2022

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PurposeTo evaluate measurement precision and to compare the Pentacam AXL (Oculus Optikgeräte, Wetzlar, German), a new optical biometer based on Scheimpflug imaging and partial coherence interferometry (PCI) with that of the OA-2000 biometer (Tomey, Nagoya, Japan), which combines swept-source optical coherence tomography (SS-OCT) and Placido-disk topography.MethodsAxial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), aqueous depth (AQD), mean keratometry (Km), astigmatism vectors J0, J45, and corneal diameter (CD) were measured in triplicate by two technical operators. Within-subject standard deviation (Sw), repeatability and reproducibility (2.77 Sw), coefficient of variation (CoV), and intraclass correlation coefficient (ICC) were used to assess the Pentacam AXL intra-observer repeatability and inter-observer reproducibility. Paired t-test and Bland-Altman plots were used to determine the agreement between the two biometers.ResultsThe new optical biometer had high intra-observer repeatability [all parameters evaluated had low CoV (<0.71%) and high ICC (>0.88)]. Inter-observer reproducibility was also excellent, with high ICC (>0.95) and low CoV (<0.52%). The 95% LoA between the new biometer and OA-2000 were insignificant for most of the parameters evaluated, especially for AL. However, the measurement agreement was moderate for CCT.ConclusionsIntra-observer repeatability and inter-observer reproducibility were excellent for all parameters evaluated using the new optical biometer based on Scheimpflug imaging and PCI. There was a high agreement between the two devices and hence could be clinically interchangeable for the measurement of most ocular parameters.

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Agreement of Corneal Diameter Measurements Obtained by a Swept-source Biometer and a Scheimpflug-based Topographer

Cited by 23 publications

References 14 publications

Agreement in anterior segment measurements between swept-source and Scheimpflug-based optical biometries in keratoconic eyes: a pilot study

Agreement in anterior segment measurements between swept-source and Scheimpflug-based optical biometries in keratoconic eyes: a pilot study

Agreement of white-to-white measurements with swept-source OCT, Scheimpflug and color LED devices

Comparison of a New Optical Biometer That Combines Scheimpflug Imaging With Partial Coherence Interferometry With That of an Optical Biometer Based on Swept-Source Optical Coherence Tomography and Placido-Disk Topography

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