Comparison of corneal elevation and pachymetry measurements made by two state of the art corneal tomographers with different measurement principles

Schröder, Simon; Langenbucher, Achim; Schrecker, Jens

doi:10.1371/journal.pone.0223770

Cited by 14 publications

(23 citation statements)

References 24 publications

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“…Furthermore, 1310 nm penetrates opaque tissues more deeply, providing clearer images of cloudy corneas than visible wavelengths [25]. The SS OCT is characterized by a high repeatability and reproducibility of the keratometry, pachymetry, Fourier, corneal elevation, anterior eye chamber, and lens parameter results, regardless of the accommodative stress, which has been confirmed in previous studies [26][27][28].…”

Section: Introductionsupporting

confidence: 73%

“…Although all examinations were performed between 10:00 and 13:00, the impact of the daily hour on FECD could be significant [ 36 , 37 ]. Moreover, the repeatability and reproducibility of SS OCT were already proved in healthy corneas, but there is a lack of such studies in larger samples of FECD eyes [ 26 , 27 , 28 ]. Variations in corneal Fourier indices or elevation might occur due to subtle misalignments caused by eye movements during examination.…”

Section: Discussionmentioning

confidence: 99%

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Corneal Analysis with Swept Source Optical Coherence Tomography in Patients with Coexisting Cataract and Fuchs Endothelial Corneal Dystrophy

et al. 2021

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This study focused on defining the characteristic features of keratometry and pachymetry elevation maps based on swept source optical coherence tomography (SS OCT) in Fuchs endothelial corneal dystrophy (FECD) eyes with a coexisting cataract. 70 eyes of 35 patients diagnosed with FECD and a coexisting cataract and 70 control eyes were included in this prospective, controlled, observational, cross-sectional study. Features characteristic of intermediately affected eyes included an increased corneal thinnest thickness (CTT) (p = 0.01), 3 and 6 mm asymmetry (p < 0.0001), higher order Fourier indices (p < 0.05 and p ≤ 0.0001, respectively), chord µ, and a posterior Ectasia Screening Index (pESI) (p < 0.01). The lack of agreement between the anterior and posterior elevation map and a significant area of negative values in the posterior map were detected. In advanced FECD eyes, our study additionally revealed decreased posterior keratometry steep (Ks), keratometry flat (Kf), keratometry average (AvgK), eccentricity (Ecc), an increased corneal apex thickness (CAT), and decreased 3 and 6 mm posterior spherical indices (p < 0.0001 for all of the above). Characteristic features of subclinical FECD, independent of the corneal thickness, can be detected by SS OCT and should be considered during the preoperative assessment of patients with a coexisting cataract.

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Section: Introductionsupporting

confidence: 73%

Section: Discussionmentioning

confidence: 99%

Corneal Analysis with Swept Source Optical Coherence Tomography in Patients with Coexisting Cataract and Fuchs Endothelial Corneal Dystrophy

et al. 2021

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“…CASIA 2 (Tomey Corporation, Nagoya, Japan), the second generation of anterior segment OCT has emerged in recent years, combines Fourier domain technology and frequency sweep source OCT technology to further optimize scanning speed (50,000 A-scans/s), scanning depth (16 × 16 × 13 mm), scanning density, and imaging resolution. However, its measurement accuracy remains unclear (11)(12)(13)(14)(15). As we all know, if a new device wants to be recognized by clinicians and be widely used in clinical practice, it will be compared with the currently recognized instrument.…”

Section: Introductionmentioning

confidence: 99%

Agreement of Anterior Segment Parameter Measurements With CASIA 2 and IOLMaster 700

et al. 2022

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PurposeTo compare the difference and agreement in central corneal thickness (CCT), keratometry (K), anterior chamber depth (ACD), aqueous depth (AQD), and lens thickness (LT) measured with CASIA 2 and IOLMaster 700 in patients with cataract.MethodsA total of 81 patients with cataract (81 eyes) scheduled for phacoemulsification were prospectively collected from March to May, 2020 in the cataract department of Zhongshan Ophthalmic Center, Sun Yat-sen University, including 43 males and 38 females with age of 61.5 ± 10.6 years. CCT, anterior Kf, anterior Ks, real Kf, real Ks, ACD, AQD, and LT were measured with CASIA 2 and IOLMaster 700. Paired t-test, intraclass correlation coefficients (ICCs), 95% limit of agreement (95% LoA), and Bland-Altman plots were performed and used to analyze the difference and agreement between the two devices.ResultsThere was no statistically significant difference in anterior K measurement with the CASIA 2 (44.3 ± 1.66 mm) and IOLMaster 700 (44.31 ± 1.67 mm, P = 0.483). Differences among the CCT, anterior Kf, real Kf, real Ks, ACD, AQD, and LT measured by the two instruments were statistically significant (P < 0.001). The ICCs of CCT, anterior Kf, anterior Ks, real Kf, real Ks, ACD, AQD, and LT measurements between the two devices were 0.892, 0.991, 0.991, 0.827, 0.817, 0.937, 0.926, and 0.997, respectively. The 95% LoA between CASIA 2 and IOLMaster 700 was −30.06 to 0.43 μm for CCT, −0.3 to 0.48 D for anterior Kf, −0.46 to −0.43 D for anterior Ks, −1.49 to −0.49 D for real Kf, −1.62 to −0.49 D for Real Ks, −0.03 to 0.24 mm for ACD, 0.04 to 0.25 mm for AQD, and −0.06 to 0.09 mm for LT.ConclusionAnterior Kf, anterior Ks, ACD, AQD, and LT have excellent agreement between the two devices. CCT, real Kf, and real Ks have moderate agreement between the two devices. It is recommended to use anterior Kf, anterior Ks, ACD, AQD, and LT interchangeably between CASIA 2 and IOLMaster 700.

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“…T he structural and refractive knowledge of the cornea is essential for the accurate diagnosis and monitoring of ectasic corneal conditions, such as keratoconus, and for the planning and implementation of surgical procedures, with special importance in the correction of astigmatism and in the field of refractive surgery. [1][2][3][4][5][6][7][8][9][10][11][12] Furthermore, the accurate analysis of the corneal structure is pivotal in the selection of the power for an intraocular lens. [1][2][3][4][5][6][7]13,14 In addition, the acquisition of the cornea's posterior surface data is relevant if the intraocular lens to be implanted has toric features.…”

mentioning

confidence: 99%

“…[1][2][3][4][5][6][7]13,14 In addition, the acquisition of the cornea's posterior surface data is relevant if the intraocular lens to be implanted has toric features. 6 Since the appearance of the first keratometers, several technologies have evolved to accurately characterize corneal morphology and several studies have tried to assess the repeatability and reliability of these modern technologies. Placido disk technology obtains the measurements of the anterior surface of the cornea following the specular reflection principle 15 ; however, the assessment of the posterior surface is one of its main limitations.…”

mentioning

confidence: 99%

Intraobserver Repeatability of Tomographic, Pachymetric, and Anatomical Measurements in Healthy Eyes Using a New Swept-Source Optical Coherence Topographer

Serrano

Jaimes

Lucas

et al. 2021

Cornea

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The purpose of this study was to evaluate the intraobserver repeatability of several corneal parameters in healthy eyes using a new swept-source optical coherence topographer.Methods: Fifty right eyes of 50 subjects were enrolled in this study. A single examiner performed 3 consecutive measurements using the Anterion swept-source optical coherence tomography. The following corneal parameters were evaluated: average keratometry (K), steep K, flat K, astigmatism, best fit sphere, and maximum keratometry on the anterior and posterior surfaces at 3 mm, average K, steep K, flat K, and astigmatism in the total corneal power map at 3 mm, central corneal thickness and thinnest point thickness in the pachymetric map, and corneal diameter. To assess the repeatability of the measurements, we calculated the following indexes: intrasubject SD (Sw), coefficient of variation, coefficient of repeatability, and intraclass correlation coefficient (ICC).Results: High repeatability was reported for all the evaluated corneal parameters, with Sw values lower than 0.027, coefficient of variation values lower than 0.066%, and coefficient of repeatability values lower than 0.187. ICC values showed a high correlation between measurements in all cases, being the lowest value for the astigmatism of the anterior surface (ICC = 0.92); for the rest, ICC values were larger than 0.98. Finally, we have not found statistically significant differences between repeated measurements (P . 0.05). Conclusions:The anterior segment measurements provided by the Anterion swept-source optical coherence tomography device show high intraobserver repeatability in healthy eyes.

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Comparison of corneal elevation and pachymetry measurements made by two state of the art corneal tomographers with different measurement principles

Cited by 14 publications

References 24 publications

Corneal Analysis with Swept Source Optical Coherence Tomography in Patients with Coexisting Cataract and Fuchs Endothelial Corneal Dystrophy

Corneal Analysis with Swept Source Optical Coherence Tomography in Patients with Coexisting Cataract and Fuchs Endothelial Corneal Dystrophy

Agreement of Anterior Segment Parameter Measurements With CASIA 2 and IOLMaster 700

Intraobserver Repeatability of Tomographic, Pachymetric, and Anatomical Measurements in Healthy Eyes Using a New Swept-Source Optical Coherence Topographer

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