Intraobserver reproducibility and interobserver agreement of demarcation line depth measurements following corneal cross linking

2019 ◽  
Vol 30 (4) ◽  
pp. 635-642
Author(s):  
Argyrios Tzamalis ◽  
Riccardo Vinciguerra ◽  
Vito Romano ◽  
Esmaeil Arbabi ◽  
Mark Batterbury ◽  
...  
Keyword(s):  
Medical Students ◽  
Confidence Interval ◽  
Correlation Coefficient ◽  
Intraclass Correlation Coefficient ◽  
Intraclass Correlation ◽  
Cross Linking ◽  
Demarcation Line ◽  
Line Depth ◽  
Collagen Cross Linking ◽  
Corneal Collagen

Purpose: The aim of this study was to evaluate the intraobserver reproducibility of demarcation line depth measurement in keratoconic patients after epithelium-off corneal collagen cross linking and assess the interobserver variability/agreement among examiners of various experience levels. Methods: 56 eyes of 56 patients undergoing corneal collagen cross linking for progressive keratoconus were enrolled. After 4 weeks, all patients underwent an anterior segment optical coherence tomography (AS-OCT; CASIA SS-1000; Tomey, Nagoya, Japan) in the cross-linked eye by four masked examiners (two medical students (S1 and S2) and two corneal fellows (F1 and F2)) in order to identify and measure the demarcation line depth in experienced and non-experienced users. The intraclass correlation coefficient and the coefficient of variation were calculated. Agreement between raters was evaluated using Bland–Altman plots, intraclass correlation coefficient and weighted-kappa statistics comparing raters in pairs. Results: The average demarcation line depth of all measurements was 254.34 ± 72.3 μm, varying from 84 to 459 μm. The intraclass correlation coefficient evaluating the reproducibility of measurements for F1 was 0.9379 (95% confidence interval (CI) =0.9035–0.9619), for the second (F2), it was 0.9837 (95% confidence interval = 0.9743–0.9901), while intraclass correlation coefficient between medical students was calculated 0.844. The overall intraclass correlation coefficient among all four observers was 0.8706 (95% confidence interval = 0.8061–0.9185). The coefficient of variation for repeated measurements was 5.981 μm (95% confidence interval = 3.966–7.471) and 3.312 μm (95% confidence interval = 2.468–3.981) for F1 and F2 raters, respectively. The percentage of demarcation line detection was 90.32%. Conclusion: The reproducibility of demarcation line measures although very good (intraclass correlation coefficient > 0.9), yielded a difference between the two experienced raters. Furthermore, the novice raters did not reach an excellent level of agreement with the expert ones showing greater variability in their recordings.

scholarly journals Corneal Collagen Cross-Linking Mushroom Shape Demarcation Line Profile After Limited Bowman’s Membrane Removal by Phototherapeutic Keratectomy

2015 ◽  
Vol 9 (1) ◽  
pp. 17-19 ◽  
Author(s):  
George D Kymionis ◽  
Michael A Grentzelos ◽  
Nektarios E Klados ◽  
Niki A Xanthopoulou ◽  
Theodore A Paraskevopoulos ◽  
...  
Keyword(s):  
Line Profile ◽  
Anterior Segment ◽  
Cross Linking ◽  
Demarcation Line ◽  
Phototherapeutic Keratectomy ◽  
Early Postoperative Complications ◽  
One Year ◽  
Line Depth ◽  
Collagen Cross Linking ◽  
Corneal Collagen

Purpose :To report a corneal collagen cross-linking (CXL) mushroom shape demarcation line profile after limited Bowman’s membrane removal by phototherapeutic keratectomy (PTK).Methods :Case report.Results :A twenty-one-year-old male with progressive keratoconus underwent mechanical epithelial debridement (at an 8.5 mm zone) followed by PTK (at a 5.0 mm zone and in a 10 μm depth) and CXL. No intra- or early postoperative complications were found. Evaluation of the corneal stromal demarcation line depth using anterior segment optical coherence tomography revealed a mushroom shape profile.Conclusion :It seems that removal of the Bowman’s layer leads to greater depth of the corneal stromal demarcation line.

Comparison between OrbscanIIz, Pentacam, Ultrasound Pachymetry (Tomey SP-100) at Different Stages of Keratoconus

2020 ◽  
pp. 7-33
Author(s):  
E. Pateras ◽  
Ch. Koufala
Keyword(s):  
Correlation Coefficient ◽  
Study Design ◽  
Refractive Surgery ◽  
Corneal Thickness ◽  
Cross Linking ◽  
Moderate Correlation ◽  
Measurement Systems ◽  
Ultrasound Pachymetry ◽  
Collagen Cross Linking ◽  
Corneal Collagen

Aims: To compare results of OrbscanIIz and Pentacam and Ultrasound pachymetry at different stages of keratoconus on corneal thickness. Sample and Study Design: 94 keratoconic patients participated in the study, of which 52 were men and 42 women. Keratoconus patients were measured with OrbscanIIz, Pentacam and Ultrasound pachymetry in pre-operation examinations for corneal collagen cross-linking. The patients belong to different keratoconus stages. Place and Duration of Study: University of West Attica Dept Biomedical Sciensce Course Optics & Optometry in collaboration with Athens “Ophthalmologico” Clinic during the period between October 2017 to January 2019. Methodology: Corneal Pachymetry maps correlation of three types of corneal pachymeters OrbscanIIz, Pentacam and Ultrasound pachymetry (Tomey SP-100 Pachymeter). The measurements of the thinnest point of the cornea from each patient were collected at different stages of keratoconus and compared. Results: A sample of 188 eyes were measured at different stages of keratoconus and compared for the thinnest corneal thickness with three different measurement systems, OrbscanIIz ,Pentacam and Ultrasound pachymetry. At sublinical stage Orbscan-Pentacam had Correlation coefficient r=0,7971, Orbscan-Ultrasound r=0,7483 and Pentacam-Ultrasound r=0,9442. At 1st stage Orbscan-Pentacam had Correlation coefficient r=0,8913, Orbscan-Ultrasound r=0,8151 and Pentacam-Ultrasound r=0,8151. At 2nd stage Orbscan-Pentacam had Correlation coefficient r=0,9339, Orbscan-Ultrasound r=0,8819 and Pentacam-Ultrasound r=0,9633. For 3rd stage Orbscan-Pentacam had Correlation coefficient r=0,8317, Orbscan-Ultrasound r=0,8457 and Pentacam-Ultrasound r=0,9633. For 4th stage Orbscan-Pentacam had Correlation coefficient r=-0,4655, Orbscan-Ultrasound r=0,3089 and Pentacam-Ultrasound r=0,9633. In Iatrogenic keratoectasiaafter refractive surgery Orbscan-Pentacam had Correlation coefficient r=0,9327, Orbscan-Ultrasound r=0,3089 and Pentacam-Ultrasound r=0,9859. Conclusion: Statistical differences between OrbscanIIz, Pentacam and Ultrasound pachymetry were found for corneal thickness in all stages of keratoconus for the thinnest point measured. Orbscan-Pentacam have statistical significant differences but weak to moderate correlation. Orbscan-Ultasound have also statistical significant differences their correlation is very weak, while Pentacam-Ultrasound have statistical significant differences smaller as the previous but their correlation is very strong at all stages of keratoconus.

scholarly journals Comparison for Kmean and Astigmatism for Orbscan IIz and Pentacam at Different Stages of Keratoconus - A Clinical Study

2020 ◽  
pp. 30-40
Author(s):  
E. Pateras ◽  
Ch. Koufala
Keyword(s):  
Clinical Study ◽  
Correlation Coefficient ◽  
Strong Correlation ◽  
Refractive Surgery ◽  
Topographic Maps ◽  
Cross Linking ◽  
Stage 4 ◽  
Stage 1 ◽  
Collagen Cross Linking ◽  
Corneal Collagen

Aims: To compare results of Orbscan IIz and Pentacam at different stages of keratoconus on Kmean and Astigmatism. Sample and Study Design: 94 keratoconus patients were included in the study, of which 52 were men and 42 women. Keratoconus patients were screened with Orbscan IIz and Pentacam before undergoing corneal collagen cross-linking. The patients were distributed according to different keratoconus stages. Place and Duration of Study: University of West Attica Dept Biomedical Sciensce Course Optics & Optometry in collaboration with Athens “Ophthalmiatrio” Clinic during the period between October 2017 to January 2019. Methodology: Topographic maps correlation of two types of corneal topographers Orbscan IIz and Pentacam. The Kmean values and the Astigmatism presented at different stages of keratoconus were compared. Results: A Sample of 188 eyes were measured having, 20 eyes (10.6%) with subclinical keratoconus, the correlation coefficient r for Kmean values between Orbscan IIz and Pentacam was 0.9758 (P<0.0001), 44 eyes (23.3%) at stage 1 with the correlation coefficient r=0.8482 (P<0.0001),  33 eyes (17.6%) at stage 2 with the correlation coefficient r=0.8147 (P<0.0001), 67 eyes (35.6%) at stage 3 with the correlation coefficient r=0.797 (P<0.0001), 10 eyes (5.3%) at stage 4 with the correlation coefficient r=0.8455 (P=0.0021), 8 eyes (4.4%) with iatrogenic keratoectasia after refractive surgery having correlation coefficient r=0.928 (P=0.0009). Conclusion: Statistical differences between Orbscan IIz and Pentacam were found for Kmean in all stages of keratoconus. The performance for Kmean measurement of the corneal topographers Orbscan IIz and Pentacam is satisfactory for both systems in various stages of keratoconus having a very strong correlation (Correlation coefficient r ranged from 0.9758 to 0.7970). Statistical differences between Orbscan IIz and Pentacam were evident also at the Astigmatism measurements at stage 3 and 4.

Speech perception, real-ear measurements and self-perceived hearing impairment after remote and face-to-face programming of hearing aids: A randomized single-blind agreement study

2019 ◽  
pp. 1357633X1988354 ◽  
Author(s):  
Frederic Venail ◽  
Marie C Picot ◽  
Gregory Marin ◽  
Sylvain Falinower ◽  
Jacques Samson ◽  
...  
Keyword(s):  
Speech Perception ◽  
Confidence Interval ◽  
Correlation Coefficient ◽  
Intraclass Correlation Coefficient ◽  
Hearing Aids ◽  
Hearing Aid ◽  
Intraclass Correlation ◽  
Speech Understanding ◽  
Face To Face ◽  
Single Blind

Introduction Current literature does not provide strong evidence that remote programming of hearing aids is effective, despite its increasing use by audiologists. We tested speech perception outcomes, real-ear insertion gain, and changes in self-perceived hearing impairment after face-to-face and remote programming of hearing aids in a randomized multicentre, single-blind crossover study. Methods Adult experienced hearing aid users were enrolled during routine follow-up visits to audiology clinics. Hearing aids were programmed both face to face and remotely, then participants randomly received either the face-to-face or remote settings in a blinded manner and were evaluated 5 weeks later. Participants then received the other settings and were evaluated 5 weeks later. Results Data from 52 out of 60 participants were analysed. We found excellent concordance in performance of hearing aids programmed face to face and remotely for speech understanding in quiet (phonetically balanced kindergarten test – intraclass correlation coefficient of 0.92 (95% confidence interval: 0.87–0.95)), and good concordance in performance for speech understanding in noise (phonetically balanced kindergarten +5 dB signal-to-noise ratio – intraclass correlation coefficient of 0.71 (95% confidence interval: 0.55–0.82)). Face-to-face and remote programming took 10 minutes (±2.9) and 10 minutes (±2.8), respectively. Real-ear insertion gains were highly correlated for input sound at 50, 65 and 80 dB sound pressure levels. The programming type did not affect the abbreviated profile of hearing aid questionnaire scores. Conclusions In experienced hearing aid users, face-to-face and remote programming of hearing aids give similar results in terms of speech perception, with no increase in the time spent on patients’ care and no difference in self-reported hearing benefit. ClinicalTrials.gov Identifier NCT02589561

Visibility and Depth of the Stromal Demarcation Line After Corneal Collagen Cross-Linking Using Anterior Segment Optical Coherence Tomography

Cornea ◽  
2018 ◽  
Vol 37 (5) ◽  
pp. 567-573 ◽  
Author(s):  
Louis Lhuillier ◽  
Cedric Ghetemme ◽  
Mathilde Boiché ◽  
Rekia Yahia ◽  
Naila Houmad ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Anterior Segment ◽  
Cross Linking ◽  
Optical Coherence ◽  
Demarcation Line ◽  
Collagen Cross Linking ◽  
Corneal Collagen
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