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The Interday Repeatability of Parameters for the Assessment of Progressive Disease in Subjects With Less Advanced Keratoconus

Gustafsson, Ingemar LU ; Bergström, Anders LU ; Cardiakides, Anna LU ; Ivarsen, Anders and Hjortdal, Jesper Østergaard (2021) In American Journal of Ophthalmology 225. p.38-46
Abstract

Purpose: To evaluate the interday repeatability in the measurement of parameters used for the detection of progression of keratoconus by prediction limits (PL) for single measurements, and the repeatability coefficient (RC) for the mean of replicate measurements. Design: Prospective reliability analysis for cases and control eyes. Methods: Twenty-five eyes in 25 subjects with KC and 25 eyes in 25 healthy controls were included. Four consecutive measurements were made, 3 days apart, with a Pentacam HR tomographic instrument (denoted the Pentacam) and a Nidek ARK 560-A auto-keratometer (denoted the keratometer). Main outcome measures were the intra- and interday RC of parameters used in the detection of progression of keratoconus.... (More)

Purpose: To evaluate the interday repeatability in the measurement of parameters used for the detection of progression of keratoconus by prediction limits (PL) for single measurements, and the repeatability coefficient (RC) for the mean of replicate measurements. Design: Prospective reliability analysis for cases and control eyes. Methods: Twenty-five eyes in 25 subjects with KC and 25 eyes in 25 healthy controls were included. Four consecutive measurements were made, 3 days apart, with a Pentacam HR tomographic instrument (denoted the Pentacam) and a Nidek ARK 560-A auto-keratometer (denoted the keratometer). Main outcome measures were the intra- and interday RC of parameters used in the detection of progression of keratoconus. Results: The most repeatable parameter obtained with the Pentacam was the curvature power of the central flat meridian (K1, 0.44 D [RC], -0.55 to 0.60 diopter [D] [PL]), followed by the central steep meridian (K2, 0.72 D [RC], -0.90 to 0.94 D [PL]). The interday repeatability of K1 and K2 was similar when using the keratometer (K1, 0.32 D [RC], -0.66 to 0.57 D [PL], K2, 0.93 D [RC], -1.36 to 1.08 D [PL]). The interday repeatability of the curvature power of the steepest point (Kmax, 0.84 D [RC], -0.90 to 1.11 D [PL]) would benefit from being stratified: RC = 0.44 D and PL = -0.49 to 0.67 D for Kmax < 49.0 D, and RC = 1.08 D and PL = -1.19 to 1.42 D for Kmax ≥ 49.0 D. Conclusions: The interday repeatability of measurements, single or replicate, in subjects with keratoconus should be considered when diagnosing progressive disease. K1 exhibited the best intraday repeatability. Kmax benefits from being stratified according to disease severity.

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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
American Journal of Ophthalmology
volume
225
pages
9 pages
publisher
Elsevier
external identifiers
  • pmid:33422466
  • scopus:85101636354
ISSN
0002-9394
DOI
10.1016/j.ajo.2020.12.028
language
English
LU publication?
yes
id
3e8df55e-4a1a-4c55-8e7c-2439157b222b
date added to LUP
2021-03-15 08:35:24
date last changed
2024-06-14 11:27:59
@article{3e8df55e-4a1a-4c55-8e7c-2439157b222b,
  abstract     = {{<p>Purpose: To evaluate the interday repeatability in the measurement of parameters used for the detection of progression of keratoconus by prediction limits (PL) for single measurements, and the repeatability coefficient (RC) for the mean of replicate measurements. Design: Prospective reliability analysis for cases and control eyes. Methods: Twenty-five eyes in 25 subjects with KC and 25 eyes in 25 healthy controls were included. Four consecutive measurements were made, 3 days apart, with a Pentacam HR tomographic instrument (denoted the Pentacam) and a Nidek ARK 560-A auto-keratometer (denoted the keratometer). Main outcome measures were the intra- and interday RC of parameters used in the detection of progression of keratoconus. Results: The most repeatable parameter obtained with the Pentacam was the curvature power of the central flat meridian (K1, 0.44 D [RC], -0.55 to 0.60 diopter [D] [PL]), followed by the central steep meridian (K2, 0.72 D [RC], -0.90 to 0.94 D [PL]). The interday repeatability of K1 and K2 was similar when using the keratometer (K1, 0.32 D [RC], -0.66 to 0.57 D [PL], K2, 0.93 D [RC], -1.36 to 1.08 D [PL]). The interday repeatability of the curvature power of the steepest point (Kmax, 0.84 D [RC], -0.90 to 1.11 D [PL]) would benefit from being stratified: RC = 0.44 D and PL = -0.49 to 0.67 D for Kmax &lt; 49.0 D, and RC = 1.08 D and PL = -1.19 to 1.42 D for Kmax ≥ 49.0 D. Conclusions: The interday repeatability of measurements, single or replicate, in subjects with keratoconus should be considered when diagnosing progressive disease. K1 exhibited the best intraday repeatability. Kmax benefits from being stratified according to disease severity.</p>}},
  author       = {{Gustafsson, Ingemar and Bergström, Anders and Cardiakides, Anna and Ivarsen, Anders and Hjortdal, Jesper Østergaard}},
  issn         = {{0002-9394}},
  language     = {{eng}},
  pages        = {{38--46}},
  publisher    = {{Elsevier}},
  series       = {{American Journal of Ophthalmology}},
  title        = {{The Interday Repeatability of Parameters for the Assessment of Progressive Disease in Subjects With Less Advanced Keratoconus}},
  url          = {{http://dx.doi.org/10.1016/j.ajo.2020.12.028}},
  doi          = {{10.1016/j.ajo.2020.12.028}},
  volume       = {{225}},
  year         = {{2021}},
}