Elke O Kreps1, Marta Jimenez-Garcia2, Ikram Issarti2, Ilse Claerhout3, Carina Koppen2, Jos J Rozema2. 1. Department of Medicine and Health Sciences, University of Ghent, Ghent, Belgium; Department of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium. Electronic address: elke.kreps@ugent.be. 2. Department of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium; Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium. 3. Department of Medicine and Health Sciences, University of Ghent, Ghent, Belgium; Department of Ophthalmology, Maria Middelares General Hospital, Ghent, Belgium.
Abstract
PURPOSE: To evaluate the repeatability of an extensive number of relevant indices with the Pentacam HR in keratoconus of varying severity and normal eyes. DESIGN: Reliability analysis. METHODS: This study was performed at Antwerp University Hospital, Belgium, and enrolled 20 healthy volunteers (20 eyes) and 69 patients (69 eyes) with keratoconus. Three consecutive measurements were performed by the same operator with Pentacam HR in keratoconus and normal eyes. Exclusion criteria included past ocular surgery, recent rigid contact lens wear, and corneal scarring. The keratoconus group was subdivided according to the Belin/Ambrosio total deviation value: subclinical, mild, and moderate. The within-subject standard deviation and repeatability limit were computed for repeatability assessment. The tolerance index (TI) was calculated to compare across parameters with different measurement scales. For the sample size included, TI > 0.36 signified statistical significance at the 0.05 level. RESULTS: Repeatability in subclinical keratoconus did not differ significantly from controls (P > .05), except for wavefront aberrations. In mild keratoconus, 11 of 18 (61.1%) anterior corneal, 7 of 14 (50%) posterior corneal, 2 of 5 (40%) pachymetry, 7 of 11 (63.6%) combined, and 1 of 6 (16.7%) densitometry parameters showed significantly worse repeatability compared to controls (TI > 0.36). Repeatability of most parameters worsened in moderate disease. In particular, maximal keratometry and anterior astigmatism showed significantly worse repeatability in moderate keratoconus. CONCLUSIONS: Measurement variability of Pentacam HR is of clinical relevance when assessing for progression of keratoconus. We provide reference repeatability values and scale independent analysis of relevant corneal parameters in keratoconus of varying degrees.
PURPOSE: To evaluate the repeatability of an extensive number of relevant indices with the Pentacam HR in keratoconus of varying severity and normal eyes. DESIGN: Reliability analysis. METHODS: This study was performed at Antwerp University Hospital, Belgium, and enrolled 20 healthy volunteers (20 eyes) and 69 patients (69 eyes) with keratoconus. Three consecutive measurements were performed by the same operator with Pentacam HR in keratoconus and normal eyes. Exclusion criteria included past ocular surgery, recent rigid contact lens wear, and corneal scarring. The keratoconus group was subdivided according to the Belin/Ambrosio total deviation value: subclinical, mild, and moderate. The within-subject standard deviation and repeatability limit were computed for repeatability assessment. The tolerance index (TI) was calculated to compare across parameters with different measurement scales. For the sample size included, TI > 0.36 signified statistical significance at the 0.05 level. RESULTS: Repeatability in subclinical keratoconus did not differ significantly from controls (P > .05), except for wavefront aberrations. In mild keratoconus, 11 of 18 (61.1%) anterior corneal, 7 of 14 (50%) posterior corneal, 2 of 5 (40%) pachymetry, 7 of 11 (63.6%) combined, and 1 of 6 (16.7%) densitometry parameters showed significantly worse repeatability compared to controls (TI > 0.36). Repeatability of most parameters worsened in moderate disease. In particular, maximal keratometry and anterior astigmatism showed significantly worse repeatability in moderate keratoconus. CONCLUSIONS: Measurement variability of Pentacam HR is of clinical relevance when assessing for progression of keratoconus. We provide reference repeatability values and scale independent analysis of relevant corneal parameters in keratoconus of varying degrees.
Authors: Shengsheng Wei; Jing Li; Yong Li; Yaohua Zhang; Yan Cai; Jing Du; Jianguo Liu; Yan Wang Journal: Int Ophthalmol Date: 2022-09-24 Impact factor: 2.029