REPEATABILITY AND RELIABILITY OF CORNEAL TOMOGRAPHY IN KERATOCONUS PATIENTS WITH CORNEAL ALLOGENIC INTRASTROMAL RING SEGMENTS
Published 2026 - 30th ESCRS Winter Meeting
Reference: FP05.14 | Type: Free Paper | DOI: 10.82333/qw2p-g560
Authors: Ugur Tunc* 1 , Dilan Colak 2 , Burcu Yakut 3 , Feyza Keskin Pek 4 , Metin Suleymanzade 5 , Sepide Lotfi 5 , Aylin Kilic 5
1Ophthalmology,Medipol University,Istanbul,Türkiye, 2Ophthalmology,Beyoglu eye trainning and research hospital,Istanbul,Türkiye, 3Ophthalmology,Haseki trainning and research hospital,Istanbul,Türkiye, 4Ophthalmology,Istanbul Cam and Sakura City Hospital,Istanbul,Türkiye, 5Ophthalmology,Istanbul Biruni University ,Istanbul,Türkiye
Purpose
To evaluate 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.
Setting
This prospective, observational study was conducted at the Istanbul Swiss Vision Clinic between August 2022 and July 2023. The study adhered to the tenets of the Declaration of Helsinki and was approved by the Institutional Ethics Committee. Written informed consent was obtained from all participants prior to their enrollment in the study.
Methods
We included 42 eyes—20 eyes with keratoconus that had undergone CAIRS implantation and 22 healthy control eyes. All participants underwent corneal imaging using the Pentacam HR (Oculus Optikgeräte GmbH, Germany). Each eye was scanned three consecutive times during a single session. Repeatability was assessed using within-subject standard deviation (Sw), repeatability index (RI), and tolerance index (TI), while reliability was evaluated using the intraclass correlation coefficient (ICC). A TI > 0.36 was considered indicative of reduced repeatability.
Results
Anterior corneal curvature parameters (K1, K2, Kmean) and pachymetric indices showed excellent reliability (ICC > 0.90) and acceptable repeatability (TI < 0.36) in both groups. However, Kmax, anterior elevation, and most posterior corneal parameters exhibited higher variability in CAIRS-implanted eyes, with TI values exceeding 0.36. Posterior elevation demonstrated the greatest measurement variability, despite high ICC values. Thinnest corneal thickness and pachymetry at the corneal vertex remained highly repeatable (TI < 0.20).
Conclusion
CAIRS implantation alters corneal geometry, affecting the repeatability of certain tomography parameters—particularly Kmax and posterior corneal measurements. Although overall reliability remains high, clinicians should interpret small postoperative changes in these indices with caution. Pachymetric parameters retain excellent precision and can be reliably used for follow-up and progression monitoring after CAIRS surgery.