ESCRS - PO674 - Revisiting Scheimpflug And Oct Technologies In Corneal Assessment Post-Cxl: A Comprehensive Analysis

Revisiting Scheimpflug And Oct Technologies In Corneal Assessment Post-Cxl: A Comprehensive Analysis

Published 2024 - 42nd Congress of the ESCRS

Reference: PO674 | Type: Free paper | DOI: 10.82333/fk1p-0g71

Authors: Farhad Hafezi 1 , M. Enes Aydemir* 2 , Nikki L. Hafezi 3 , Mark Hillen 2 , Léonard Kollros 4 , Emilio A. Torres-Netto 5

1ELZA Institute,Zurich,Switzerland;Faculty of Medicine,University of Geneva,Geneva,Switzerland;USC Roski Eye Institute,University of Southern California,Los Angeles,United States;Department of Ophthalmology,Wenzhou Medical University,Wenzhou,China;Department of Ophthalmology,NYU Grossman School of Medicine,New York,United States, 2ELZA Institute,Zurich,Switzerland, 3ELZA Institute,Zurich,Switzerland;Faculty of Medicine and Health Sciences,University of Antwert,Edegem,Belgium, 4ELZA Institute,Zurich,Switzerland;University of Applied Sciences and Arts Northwestern Switzerland FHNW,Olten,Switzerland, 5ELZA Institute,Zurich,Switzerland;Center for Applied Biotechnology and Molecular Medicine,University of Zurich,Zurich,Switzerland;Paulista School of Medicine,Federal University of Sao Paulo (UNIFESP),São Paulo,Brazil

Purpose

To reassess the efficacy and reliability of Scheimpflug and OCT imaging technologies in evaluating corneal structural changes post-corneal cross-linking (CXL), addressing potential discrepancies in diagnosing corneal haze and keratoconus progression.

Setting

This study was conducted at the ELZA Institute, Dietikon, Switzerland.

Methods

This retrospective study analyzed 6-month post-CXL outcomes in 52 eyes of patients that underwent standard (5.4 J/cm2) and high-fluence (10 J/cm2) CXL using Scheimpflug and combined Placido disk/OCT imaging (Pentacam, Oculus, and MS-39, CSO Italia, respecitvely) to assess corneal tomographies and other related parameters. Comparative analysis focused on discrepancies in corneal densitometry and topography measurements, aiming to identify the most accurate diagnostic tool for post-CXL corneal assessment.

Results

Our findings suggest that both technologies are highly important for examining the post-CXL cornea for signs of ectasia progression. However, at 6 months after CXL, Scheimpflug imaging overestimated progression when compared to combined Placido disk/OCT imaging. The discordance between the two technologies appeared to be greater when higher fluence irradiation protocols were used. This discordance appears to be related to corneal haze, which falsifies the height data calculated from the Scheimpflug image, but shows less impact on OCT/Placido-generated data. At 12 months post CXL, the Belin Progression display partially compensated for the false positive signals generated by Scheimpflug imaging.

Conclusions

Obtaining comprensive corneal topographies/tomographies at patients post-CXL follow-up visits are the centrepiece of determining the CXL treatment efficacy, but it appears that when corneal haze is present, Scheimpflug imaging-based devices may give an overly pessimistic assessment of the cornea than Placido disk/OCT imaging-based instruments. Within this context it is worth noting that higher fluence accelerated CXL protocols – particularly epi-off protocols – can be associated with higher rates of corneal haze. It may be the case that the 6  months success rates of CXL, as determined by OCT/Placido disk imaging-based instruments, may be higher than previously reported.