Comparison of corneal measurements in keratoconus using swept‐source optical coherence tomography and combined Placido–Scheimpflug imaging

Chan, Tommy C Y; Biswas, Sayantan; Yu, Marco; Jhanji, Vishal

doi:10.1111/aos.13298

Cited by 46 publications

(39 citation statements)

References 26 publications

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“…In eyes with keratoconus, several studies have reported good repeatability in ACD, CCT, and TCT measurements using various AS-OCT and Scheimpflug imaging devices, including spectral-domain AS-OCT (Bioptigen Inc., Durham, North Carolina, USA and Optovue, California, USA) [ 11 , 28 ], swept-source AS-OCT (CASIA SS1000, Tomey, Nagoya, Japan), Fourier-domain AS-OCT (Casia SS-1000, Tomey Corp, Nagoya, Japan) [ 15 ], Pentacam Scheimpflug imaging (Oculus Optikgerate GmbH, Wetzlar, Germany) [ 11 , 28 ], and TMS-5 Scheimpflug imaging (Tomey, Erlangen, Germany) [ 29 ]. In keratoconus, most authors caution that AS-OCT and Scheimpflug imaging devices should not be used interchangeably for ACD, CCT, and TCT measurements [ 11 , 13 , 28 , 29 ]. Some authors, however, have reported insignificant differences in ACD and CCT measurements yielded by AS-OCT and Scheimpflug imaging in keratoconus [ 14 ].…”

Section: Discussionmentioning

confidence: 99%

“…The results of this study indicate better repeatability using Scheimpflug imaging compared to AS-OCT in AL, ACD, CCT, and TCT. This is in contrast to previous studies, where Fourier-domain AS-OCT (Casia SS-1000, Tomey Corp, Nagoya, Japan) was more repeatable than Scheimpflug imaging (Pentacam HR, Oculus, Wetzlar, Germany) for CCT, TCT, and ACD in patients with keratoconus [ 13 ], while AS-OCT (CASIA SS-1000, Tomey, Nagoya, Japan) was more repeatable than Scheimpflug imaging (TMS-5, Tomey, Erlangen, Germany) for CCT in patients with keratoconus [ 29 ].…”

Section: Discussionmentioning

confidence: 99%

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

Gokul

McGhee

et al. 2021

PLoS ONE

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Purpose To compare the repeatability and agreement in biometric measurements using Spectral Domain Anterior Segment OCT (AS-OCT, REVO-NX, Optopol) and Scheimpflug tomography (Pentacam-AXL, Oculus) in keratoconus. Methods Prospective case series at a university hospital tertiary center. Axial length (AL), anterior chamber depth (ACD), central corneal thickness (CCT), and thinnest corneal thickness (TCT) were measured using both devices in patients with keratoconus. Three groups were analyzed: eyes with no prior crosslinking or contact lens wear (Group A), eyes with prior crosslinking (Group B), and eyes with prior contact lens wear (Group C). Repeatability and agreement of measurements were analyzed. Results The study comprised of 214 eyes of 157 subjects. In Group A (n = 95 eyes), Group B (n = 86 eyes), and Group C (n = 33 eyes), intraclass correlation coefficient (ICC) was higher than 0.90 for all examined parameters, except for ACD readings in Group A with the REVO-NX (ICC = 0.83). Differences in ACD, TCT, and CCT were significantly different between the two devices for Groups A, B and C (p<0.05). AL measurements differed significantly in Groups A and B (p<0.05) but not in Group C (p = 0.18). Repeatability did not vary significantly between Groups A, B, or C in any parameter with both devices (p>0.05). There was poor agreement between the two devices across all parameters (p<0.05). Conclusions Both devices demonstrated good repeatability but poor agreement across AL, ACD, CCT and TCT measurements. There was no significant difference in repeatability in virgin eyes compared to eyes with prior crosslinking or contact lens wear, however, the interchangeable use of the two devices is not recommended.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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

Gokul

McGhee

et al. 2021

PLoS ONE

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“…These have set the peripheral CT measurements on a distance of 2.5 mm and 4.0 mm, respectively, to the corneal vertex, and showed smaller CT readings at all locations with OCT instrument, as well as poor agreement between Visante and Sirius with 95% LoA of − 42.7 to − 2.0 μm for CCT measurement, and − 42.8 to 24.0 μm, − 59.1 to 7.6 μm, − 77.5 to 9.2 μm, and − 51.6 to 0.4 μm, respectively for 2.5 mm temporally, nasally, superiorly, and inferiorly, and − 86.1 to − 32.9 μm, − 112.2 to − 22.8 μm, − 88.7 to 15.2 μm, and − 128.9 to 6.2 μm, respectively, for 4.0 mm temporally, nasally, superiorly, and inferiorly. OCT instruments tended to underestimate the CCT values as compared to Scheimpflug-based devices in the normal cornea [11,26,[31][32][33][34][35][36][37], and SS-OCT is not an exception [17][18][19][38][39][40][41].…”

Section: Discussionmentioning

confidence: 99%

The precision and agreement of corneal thickness and keratometry measurements with SS-OCT versus Scheimpflug imaging

et al. 2020

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Purpose: To assess the repeatability and reproducibility of swept-source optical coherence tomography (SS-OCT) and Scheimpflug system and evaluate the agreement between the two systems in measuring multiple corneal regions in children. Methods: Pachymetric and keratometric maps for both systems were evaluated. Central, midperipheral and peripheral corneal thickness (CT), keratometry and astigmatism power vectors were recorded. The three outcomes yielded by the same observer were used to assess intraobserver repeatability. The differences in the mean values provided by each observer were used to evaluate interobserver reproducibility. Within-subject standard deviation, test-retest repeatability (TRT) and coefficient of variation (CoV) were used to analyze the intraobserver repeatability and interobserver reproducibility. Paired T-test and Bland-Altman were used to appraise interdevice agreement. Results: Seventy-eight eyes of 78 children were included. The CoV was ≤2.12 and 1.10%, respectively, for repeatability and reproducibility. TRT and CoV were lower for central and paracentral CT measurements than for peripheral measurements. The SS-OCT device generated higher precision when acquiring CT data, whereas Scheimpflug system showed higher reliability when measuring corneal keratometry. Although the CT readings measured using SS-OCT were significantly thinner than Scheimpflug device (P < 0.001), the central and thinnest CT values were still of high agreement. The interdevice agreement of keratometry measurement was high for the central corneal region and moderate for the paracentral and peripheral areas. Conclusions: The precision of CT measurements by SS-OCT was higher, while the reliability of keratometry measurements by the Scheimpflug system was higher in children. Apart from the measured values in the central corneal region, the thickness and keratometry readings should not be considered interchangeable between the two systems.

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“…Corneal tomography (e.g. Scheimpflug or OCT) is the most commonly used modality to diagnose keratoconus due to its ability to detect posterior corneal elevation abnormalities even in mild or subclinical disease …”

Section: Clinical Applications Of Corneal Topographymentioning

confidence: 99%

“…Scheimpflug or OCT) is the most commonly used modality to diagnose keratoconus due to its ability to detect posterior corneal elevation abnormalities even in mild or subclinical disease. 8 Several indices such as the inferior-superior index and KISA% index may facilitate the differentiation of keratoconus from normal corneas. 9,10 The central K value, an expression of central corneal steepening, is the average of the dioptric powers on rings 2-4 of the Placido disc and a central K value ≥47.2 diopters is indicative of keratoconus.…”

Section: Diagnosis Of Keratoconusmentioning

confidence: 99%

Applications of corneal topography and tomography: a review

Fan

Chan

Prakash³

et al. 2018

Clinical Exper Ophthalmology

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103

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Corneal imaging is essential for diagnosing and management of a wide variety of ocular diseases. Corneal topography is used to characterize the shape of the cornea, specifically, the anterior surface of the cornea. Most corneal topographical systems are based on Placido disc that analyse rings that are reflected off the corneal surface. The posterior corneal surface cannot be characterized using Placido disc technology. Imaging of the posterior corneal surface is useful for diagnosis of corneal ectasia. Unlike corneal topographers, tomographers generate a three-dimensional recreation of the anterior segment and provide information about the corneal thickness. Scheimpflug imaging is one of the most commonly used techniques for corneal tomography. The cross-sectional images generated by a rotating Scheimpflug camera are used to locate the anterior and posterior corneal surfaces. The clinical uses of corneal topography include, diagnosis of corneal ectasia, assessment of corneal astigmatism, and refractive surgery planning. This review will discuss the applications of corneal topography and tomography in clinical practice.

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Comparison of corneal measurements in keratoconus using swept‐source optical coherence tomography and combined Placido–Scheimpflug imaging

Cited by 46 publications

References 26 publications

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

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

The precision and agreement of corneal thickness and keratometry measurements with SS-OCT versus Scheimpflug imaging

Applications of corneal topography and tomography: a review

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