Variability in Oculus Pentacam Tomographer Measurements in Patients With Keratoconus

Vianna, Lucas Monferrari Monteiro; Muñoz, Beatriz; Hwang, Frank S.; Gupta, Arusha; Jun, Albert S.

doi:10.1097/ico.0000000000000344

Cited by 20 publications

(22 citation statements)

References 20 publications

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“…This finding is consistent with the recent report by Vianna et al 16 of increased variability in certain measures with Pentacam in patients with high topographic astigmatism.…”

Section: Discussionsupporting

confidence: 93%

Differential precision of corneal Pentacam HR measurements in early and advanced keratoconus

et al. 2015

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“…This finding is consistent with the recent report by Vianna et al 16 of increased variability in certain measures with Pentacam in patients with high topographic astigmatism.…”

Section: Discussionsupporting

confidence: 93%

Differential precision of corneal Pentacam HR measurements in early and advanced keratoconus

et al. 2015

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“…The precision of measurements in our study was found to be best for the Pentacam HR, and better in healthy than in keratoconic eyes, which is in line with previous studies 24,25 . Intra-observer agreement was generally better than inter-observer agreement in both groups, which is also consistent with previous studies 15,25 .…”

Section: Discussionsupporting

confidence: 93%

Improving precision for detecting change in the shape of the cornea in patients with keratoconus

Brunner

Czanner

Vinciguerra

et al. 2018

Sci Rep

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To investigate a method for precision analysis to discriminate true corneal change from measurement imprecision in keratoconus (KC). Thirty patients with KC and 30 healthy controls were included. Coefficients of repeatability and limits of agreement (LOA) were compared using multiple measurements for inter-observer and inter-device agreement with the Pentacam HR, Orbscan IIz, and Tomey Casia SS-1000. Correlation of repeated measurements was evaluated using a linear mixed effect model (also called random effect model). A formula was derived for the theoretical expected change in precision and compared with measured change. Correlation between measurements from the same eye was small (R = 0.13). The 99.73% LOA (3 SD) of the mean of three measurements, provided better precision than 95% LOA (2 SD) of single cut-off values as expected from statistical theory for uncorrelated measurements for evidence of a significant change in corneal shape in patients with keratoconus. This enabled the determination of cut-off values for the detection of true change in corneal shape. The mean of three repeated measurements will provide better precision when there is minimal correlation. Three (rather than two) standard deviations provides a precise estimate of the LOA within or between observers and can be used as a reliable measure for identifying stage-independent corneal shape changes (progression) in keratoconus.

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“…Some variability exists in repeat measurements in keratoconic eyes using the same imaging device,25 and mild variability exists when imaging both keratoconic and normal corneas when using different devices 26. For these reasons, we cannot completely extrapolate our findings to other studies using different imaging technology, and we chose to report the CIs specifically to provide some sense of the possible variability that could exist.…”

Section: Discussionmentioning

confidence: 99%

Prevalence of keratoconus in paediatric patients in Riyadh, Saudi Arabia

Torres-Netto¹,

et al. 2018

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Variability in Oculus Pentacam Tomographer Measurements in Patients With Keratoconus

Abstract: Pentacam measurements show increased variability in patients with keratoconus. The degree of variability correlates with TA.

Cited by 20 publications

References 20 publications

Differential precision of corneal Pentacam HR measurements in early and advanced keratoconus

Differential precision of corneal Pentacam HR measurements in early and advanced keratoconus

Improving precision for detecting change in the shape of the cornea in patients with keratoconus

Prevalence of keratoconus in paediatric patients in Riyadh, Saudi Arabia

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