Keratoconus Progression Up To 5 Year Following Corneal Cross-Linking: Defining Personalized Keratometric Repeatability Thresholds

Published 2022 - 40th Congress of the ESCRS

Reference: FPS10.11 | Type: Free paper | DOI: 10.82333/19md-5473

Authors: Ji-Peng Olivia Li* ¹ , Howard Maile ² , Marcello Leucci ¹ , Bruce Allan ¹ , Stephen Tuft ¹ , Nikolas Pontikos ² , Daniel Gore ¹

¹Cornea and External Disease,Moorfields Eye Hospital,London,United Kingdom, ²Institute of Ophthalmology,UCL,London,United Kingdom

Purpose

To describe keratometry repeatability limits using Pentacam that adapt to keratoconus severity. To use these limits to propose a more reliable and personalised progression threshold to assess for progression following crosslinking, and to report our results of keratoconus progression five years following pulsed high-fluence corneal crosslinking (CXL).

Setting

This study is a retrospective interventional case series performed at Moorfields Eye Hospital, a large tiertiary referral centre in London, United Kingdom.

Methods

We analyzed 9341 eyes of 5025 patients in a multi ethnic cohort recruited from 26th January 2011 to 31 November 2021 and used the first two Pentacam scans for each eye from each visit. We used a variation of Bland Altman analysis to generate personalized keratometry repeatability limits by using V-shaped limits of agreement (LOA) from repeated keratometric data (Kmax, front K1, and back K2). We then used these thresholds to define progression, with a survival analysis to determine the proportion of eyes with keratoconus stabilization after CXL. We also undertook a regression analysis to identify predictors for continued progression.

Results

Adaptive, personalised thresholds for progression based on K1, K2, and Kmax from Scheimpflug keratometry were created. Defining progression as change in two parameters beyond the limit of agreement resulted in a crosslinking failure rate of 5% at 5 years, compared to 3% when using progression parameters that did not closely adapt to severity of disease. We found that increasing age reduces the risk of continued progression after CXL (HR=0.96), while increasing astigmatism and non-white ethnicity also increases the risk (HR 1.17 and 1.92 respectively).

Conclusions

Using an adaptive, personalised threshold identifies more patients as having progressed compared to traditional progression definitions. Accelerated corneal CXL achieves stability in the majority of eyes with keratoconic at five years. Younger age, higher astigmatism and non-white ethnicity are risk factors for continued keratoconus progression.