Repeatability and Reliability of Corneal Tomography in Keratoconus Patients with Corneal Allogenic Intrastromal Ring Segments.
5 affiliations
- 1Department of Ophthalmology, Istanbul Medipol University, Faculty of Medicine, Istanbul, Türkiye.
- 2Department of Ophthalmology, Beyoglu Eye Training ad Research Hospital, Istanbul, Türkiye.
- 3Department of Ophthalmology, Haseki Training and Research Hospital, Istanbul, Türkiye.
- 4Department of Ophthalmology, Cam and Sakura City Hospital; Istanbul, Türkiye.
- 5Department of Ophthalmology, Istanbul Biruni University, Istanbul, Türkiye.
Abstract
Objectives
To assess the repeatability and reliability of anterior and posterior corneal measurements in keratoconus patients who underwent corneal allogenic intrastromal ring segment (CAIRS) implantation using a Scheimpflug-based tomography system.Methods
This prospective observational study included 42 eyes: 20 keratoconic eyes that had undergone CAIRS implantation and 22 healthy controls. All participants were imaged with the Pentacam HR (Oculus Optikgeräte GmbH, Germany). Each eye underwent three consecutive scans during a single session. Repeatability was evaluated using within-subject standard deviation (Sw), repeatability index (RI), and tolerance index (TI), and reliability was assessed using intraclass correlation coefficients (ICC). A TI>0.36 was considered indicative of reduced repeatability.Results
Anterior corneal curvature parameters (K1 and K2) and pachymetric indices demonstrated excellent reliability (ICC>0.90) and acceptable repeatability (TI<0.36). In contrast, CAIRS-implanted eyes exhibited greater variability in Kmax, Kmean, anterior elevation, and several posterior corneal metrics, with TI values exceeding 0.36. Despite having high ICC values, posterior elevation showed the greatest variability. Pachymetry at the corneal vertex and the thinnest corneal thickness remained highly reproducible (TI 0.08 and 0.18, respectively), suggesting strong measurement accuracy.Conclusion
The implantation of CAIRS alters the shape of the cornea and decreases the repeatability of several tomography-derived metrics, especially posterior corneal indices and Kmax. Although overall reliability remains high, clinicians should cautiously interpret small postoperative changes in monitoring these parameters. Pachymetric measurements maintain excellent precision and can be reliably used for postoperative follow-up and progression assessment after CAIRS surgery.
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BibTeX
@article{tunc2026repeatability,
title = {{Repeatability and Reliability of Corneal Tomography in Keratoconus Patients with Corneal Allogenic Intrastromal Ring Segments.}},
author = {Ugur Tunc and Dilan Colak and Burcu Yakut and Fatma FeyzaNur Keskin Perk and Metin Suleymanzade and Sepideh Lotfi and Aylin Kılıç},
journal = {Beyoglu eye journal},
year = {2026},
month = oct,
doi = {10.14744/bej.2026.80090},
url = {https://europepmc.org/article/MED/42898753},
note = {CC BY-NC},
}
RIS
TY - JOUR
TI - Repeatability and Reliability of Corneal Tomography in Keratoconus Patients with Corneal Allogenic Intrastromal Ring Segments.
AU - Ugur Tunc
AU - Dilan Colak
AU - Burcu Yakut
AU - Fatma FeyzaNur Keskin Perk
AU - Metin Suleymanzade
AU - Sepideh Lotfi
AU - Aylin Kılıç
PY - 2026
DA - 2026/10/01
JO - Beyoglu eye journal
DO - 10.14744/bej.2026.80090
UR - https://europepmc.org/article/MED/42898753
AB - Objectives To assess the repeatability and reliability of anterior and posterior corneal measurements in keratoconus patients who underwent corneal allogenic intrastromal ring segment (CAIRS) implantation using a Scheimpflug-based tomography system.Methods This prospective observational study included 42 eyes: 20 keratoconic eyes that had undergone CAIRS implantation and 22 healthy controls. All participants were imaged with the Pentacam HR (Oculus Optikgeräte GmbH, Germany). Each eye underwent three consecutive scans during a single session. Repeatability was evaluated using within-subject standard deviation (Sw), repeatability index (RI), and tolerance index (TI), and reliability was assessed using intraclass correlation coefficients (ICC). A TI>0.36 was considered indicative of reduced repeatability.Results Anterior corneal curvature parameters (K1 and K2) and pachymetric indices demonstrated excellent reliability (ICC>0.90) and acceptable repeatability (TI<0.36). In contrast, CAIRS-implanted eyes exhibited greater variability in Kmax, Kmean, anterior elevation, and several posterior corneal metrics, with TI values exceeding 0.36. Despite having high ICC values, posterior elevation showed the greatest variability. Pachymetry at the corneal vertex and the thinnest corneal thickness remained highly reproducible (TI 0.08 and 0.18, respectively), suggesting strong measurement accuracy.Conclusion The implantation of CAIRS alters the shape of the cornea and decreases the repeatability of several tomography-derived metrics, especially posterior corneal indices and Kmax. Although overall reliability remains high, clinicians should cautiously interpret small postoperative changes in monitoring these parameters. Pachymetric measurements maintain excellent precision and can be reliably used for postoperative follow-up and progression assessment after CAIRS surgery.
SN - 2459-1777
SN - 2587-0394
ER -