Comparison of Scheimpflug and swept-source anterior segment optical coherence tomography in normal and keratoconus eyes

Ghoreishi, S.M.; Mortazavi, Seyed Ali Akbar; Abtahi, Zahra-Alsadat; Abtahi, Mohammad‐Ali; Sonbolestan, Seyed Ali; Abtahi, Seyed‐Hossein; Mohammadinia, Mohadeseh; Isfahani, Kimia Nekouie

doi:10.1007/s10792-016-0347-8

Cited by 16 publications

(36 citation statements)

References 17 publications

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“…A similar outcome has been reported by Szalai et al [18], which was consistent with our study result. Ghoreishi et al [38] noticed a high agreement between CASIA and Pentacam HR (95% LoA, − 0.24 to 0.54 D) in adults. As compared with the peripheral regions, agreement for paracentral keratometry measurements was even lower, which resulted from the abnormal precision of Pentacam HR for keratometry measurements in this area.…”

Section: Discussionmentioning

confidence: 95%

“…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%

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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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Section: Discussionmentioning

confidence: 95%

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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“…A good agreement was noted between Scheimpflug and OCT devices in unoperated eyes, but most studies only confirmed the high correlations of measurements among devices without affirming their interchangeability. In other studies, significant differences were shown in mean keratometry between Pentacam and different OCT devices . Good agreement in anterior and posterior keratometric indices was reported between Scheimpflug (Pentacam and Galilei, respectively) and Swept source OCT (Casia) in normal corneas .…”

Section: Comparison Among Different Devices: Repeatability and Agreementmentioning

confidence: 78%

“…In other studies, significant differences were shown in mean keratometry between Pentacam and different OCT devices. [58][59][60] Good agreement in anterior and posterior keratometric indices was reported between Scheimpflug (Pentacam and Galilei, respectively) and Swept source OCT (Casia) in normal corneas. 58,60 Good agreement for anterior keratometry measurement was reported between Pentacam and Visante (time-domain anterior segment OCT).…”

Section: Agreementmentioning

confidence: 92%

“…[58][59][60] Good agreement in anterior and posterior keratometric indices was reported between Scheimpflug (Pentacam and Galilei, respectively) and Swept source OCT (Casia) in normal corneas. 58,60 Good agreement for anterior keratometry measurement was reported between Pentacam and Visante (time-domain anterior segment OCT). 59 High degree of agreement in anterior keratometry but not posterior keratometry was found between Galilei and Casia Swept source OCT. 58 Studies comparing Scheimpflug topographers and optical biometers have shown potential interchangeability in keratometry readings between them.…”

Section: Agreementmentioning

confidence: 92%

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Applications of corneal topography and tomography: a review

Fan

Chan

Prakash³

et al. 2018

Clinical Exper Ophthalmology

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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 a New Scheimpflug Camera and Swept-Source Optical Coherence Tomographer for Measurements of Anterior Segment Parameters

Huang,

Lin,

Yang

et al. 2023

Ophthalmol Ther

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Introduction This study evaluated the differences and agreement between a new Scheimpflug camera (Scansys) and a swept-source anterior segment optical coherence tomographer (CASIA 2) for measurements of the anterior segment of the eye in normal subjects. Methods This prospective study included 84 eyes from 84 normal adult subjects who underwent three consecutive measurements with the Scansys and the CASIA 2 in random order. The mean keratometry (Km), astigmatism magnitude (AST), J 0 , and J 45 vectors for both anterior and posterior corneal surfaces, central corneal thickness (CCT), thinnest corneal thickness (TCT), and anterior chamber depth (ACD) were obtained by both devices. The difference between these two devices was assessed using paired t test and violin plots. Bland–Altman plots and 95% limits of agreement (LoAs) were used to evaluate agreement. Results No statistically significant differences between the two devices were found for the anterior AST, anterior J 45 , and posterior J 45 ( P > 0.05). The remaining parameters were statistically significant ( P ≤ 0.05), but the differences not clinically significant. The violin plots showed that the distribution and probability density of the measured parameters were similar for both devices. Bland–Altman plots revealed high agreement for the measured parameters between the Scansys and CASIA 2, with narrow 95% LoAs. Conclusions In terms of assessing parameters for the anterior segment, our study indicated that Scansys and CASIA 2 generally showed significant agreement. The two devices used in this study’s assessment of all the parameters can be used interchangeably in refractive analysis.

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Comparison of Scheimpflug and swept-source anterior segment optical coherence tomography in normal and keratoconus eyes

Abstract: Although two imaging technologies had statistically numerical different output, it seems that they have a good agreement in most parameters.

Cited by 16 publications

References 17 publications

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

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

Applications of corneal topography and tomography: a review

Comparison of a New Scheimpflug Camera and Swept-Source Optical Coherence Tomographer for Measurements of Anterior Segment Parameters

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