Repeatability of Scheimpflug based corneal tomography parameters in advanced keratoconus with thin corneas

Wadhwa, Himanshu; Gokul, Akilesh; Li, Ye; Cheung, Isabella M.Y.; Angelo, Lize; McGhee, Charles N J; Ziaei, Mohammed

doi:10.1038/s41433-023-02528-6

Cited by 5 publications

(1 citation statement)

References 28 publications

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“…Although the eyes included in this study had a spectrum of keratoconus severity, measurements have been shown to have greater fluctuation with increasing severity. 21 In addition, some subjects may not have been out of contact lenses long enough before the scan, so the effect of contact lens use on the measured parameters must be taken into account, and thus, this study's findings may not apply to other groups of patients.…”

Section: Discussionmentioning

confidence: 94%

Comparing Repeatability and Agreement between Commonly Used Corneal Imaging Devices in Keratoconus

Angelo,

Gokul,

McGhee

et al. 2023

Optom Vis Sci

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Significance Keratometry and pachymetry are important for diagnosis and monitoring of keratoconus. Many corneal imaging units exist but comparison to determine repeatability and agreement are paramount for adequate keratoconus management in primary and secondary care. Purpose To evaluate the repeatability and agreement of a Placido disc-based videokeratoscope (Medmont-E300 topographer) used in primary care with spectral-domain optical coherence tomography (Revo-NX) and Scheimpflug corneal tomography (Pentacam-AXL) in secondary-care. Methods This was a prospective, single-center study where one eye was randomized to have central and thinnest corneal thickness (CCT, TCT) and maximum, mean, steep and flat keratometry (Kmax, Kmean, Ksteep and Kflat), measured with all three devices. Three measurements were completed per device to assess intra-observer repeatability. Results 110 eyes from 110 patients with keratoconus were analyzed. Repeatability was best with the Pentacam for CCT, Kmax, Kmean, Ksteep and Kflat parameters (precision = 9.21,0.8,0.38,0.52,0.58). The Medmont had better repeatability than the Revo with Kmax, Kmean, Ksteep and Kflat (precision = 1.41,1.35,1.43,1.59). Revo had the best repeatability with TCT (precision = 3.81). The intraclass correlation coefficient was ˃0.94 for all parameters in all devices. Agreement was generally poor between devices. However, there was good agreement between Pentacam and Medmont Kflat measurements (P˃.05). Conclusions Repeatability of keratometry parameters with the Pentacam and Medmont were greater than the Revo, suggesting a lower threshold for change for anterior corneal changes. The Revo had the greatest repeatability for TCT, suggesting a lower threshold for assessing thinning in disease progression and corneal-crosslinking safety. There was poor agreement between devices so devices cannot be used interchangeably.

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Section: Discussionmentioning

confidence: 94%

Comparing Repeatability and Agreement between Commonly Used Corneal Imaging Devices in Keratoconus

Angelo,

Gokul,

McGhee

et al. 2023

Optom Vis Sci

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Repeatability and agreement of two ocular biometers with single and dual Scheimpflug cameras in keratoconus eyes

Lwowski,

Krüger,

Kohnen

2024

Graefes Arch Clin Exp Ophthalmol

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Corneal Tomography in a Commercially Available Optical Coherence Tomography Device and Comparison With a Rotating Scheimpflug Camera

Kanclerz,

Radomski

2024

Eye &Amp; Contact Lens: Science &Amp; Clinical Practice

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Objective: To compare the outcomes of corneal tomography obtained with an anterior-to-posterior segment optical coherence tomography device (Revo, Optopol Technologies Sp. z o.o.) and a rotating Scheimpflug camera (Pentacam AXL, Oculus Optikgeräte, Wetzlar, Germany). Methods: In healthy subjects, agreement in stereometric parameters commonly used in cataract and refractive surgery was assessed. Comparison between the devices was performed using correlation coefficients, the Bland–Altman method, and a paired t test. Results: Results of right eyes of 78 patients (47 women) aged 25.24±5.56 years were analyzed. The flat and steep anterior keratometry values were significantly higher for Revo than Pentacam (43.65±1.58 D vs. 42.99±1.47 D; P = 0.000, and 44.53±1.57 D vs. 43.82±1.49 D; P=0.000, respectively) and showed excellent correlation (r=0.978 and 0.974, respectively). The results for maximal keratometry manifested a higher difference (45.89±1.69 D vs. 44.27±1.51 D for Revo and Pentacam, P=0.000) but were also strongly correlated (r=0.871). Revo showed significantly lower corneal thickness values than Pentacam, both for apex pachymetry (535.54±32.45 vs. 550.74±31.55 μm; P=0.000) and for thinnest pachymetry (522.58±32.16 vs. 547.25±31.95 μm; P=0.000). The correlation coefficients for anterior and posterior corneal elevation at the thinnest point showed weak positive correlation (r=0.179 and 0.185), while the correlation for corneal asphericity was moderate (r=0.317). Conclusions: There was a significant difference between keratometric values obtained with Revo and the Pentacam AXL, although the measurements showed excellent correlation. Similar results were found for corneal thickness measurements, but not for corneal surface elevation and corneal asphericity.

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Repeatability of Scheimpflug based corneal tomography parameters in advanced keratoconus with thin corneas

Cited by 5 publications

References 28 publications

Comparing Repeatability and Agreement between Commonly Used Corneal Imaging Devices in Keratoconus

Comparing Repeatability and Agreement between Commonly Used Corneal Imaging Devices in Keratoconus

Repeatability and agreement of two ocular biometers with single and dual Scheimpflug cameras in keratoconus eyes

Corneal Tomography in a Commercially Available Optical Coherence Tomography Device and Comparison With a Rotating Scheimpflug Camera

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