ESCRS - FP98 - THE EFFECT OF TOPOGRAPHY-GUIDED CORNEAL CROSSLINKING ON THE CURVATURE OF THE POSTERIOR CORNEAL SURFACE

THE EFFECT OF TOPOGRAPHY-GUIDED CORNEAL CROSSLINKING ON THE CURVATURE OF THE POSTERIOR CORNEAL SURFACE

Published 2022 - 26th ESCRS Winter Meeting

Reference: FP98 | Type: Abstracts | DOI: 10.82333/z08h-c205

Authors: Celso Cabral Costa* 1 , Emmanuel Neves 1 , João Chaves 1 , Sara Geada 1 , João Gil 1 , Esmeralda Costa 1 , Andreia Rosa 2 , Cristina Tavares 1 , Maria João Quadrado 3 , Joaquim Murta 4

1Department of Ophthalmology,Centro Hospitalar e Universitário de Coimbra (CHUC),Coimbra,Portugal, 2Unidade de Oftalmologia de Coimbra,UOC,Coimbra,Portugal, 3Clinical Academic Center of Coimbra,Clinical Academic Center of Coimbra,Coimbra,Portugal, 4Faculty of Medicine,University of Coimbra,Coimbra,Portugal

Purpose

Corneal crosslinking (CXL) is an evolving therapy for the treatment of progressive keratoconus (KC). Topography-guided CXL has been proposed as an alternative to standard CXL, targeting greater flattening of the cone apex and improved visual function. While structural changes in the posterior surface of the cornea commonly precede anterior irregularities, the irradiating effect of CXL is limited to the anterior half of the cornea and its effectiveness is usually assessed looking only at the anterior corneal surface. Our goal was to evaluate the stabilizing effect of CXL on the posterior corneal surface of patients treated with a topography-guided CXL protocol.

Setting

Unidade de Oftalmologia de Coimbra (UOC), Coimbra, Portugal

Methods

Prospective case series of keratoconus patients consecutively submitted to CXL using the KXL-II® platform (Avedro, Waltham, MA, USA). We designed a treatment protocol of centripetally increasing fluence from 5.4J/cm2 to 10J/cm2 centered on the thinnest corneal point as chosen on corneal tomographies (Oculus Pentacam, Optikgerate GmbH, Wetzlar, Germany). We collected data on pre- and post-treatment BCVA, anterior and posterior corneal curvature parameters. Post-treatment values were measured at 12 months after the intervention. Student’s t tests were used to compare pre- and post-treatment continuous variables. An α level of 0.05 was considered as significant.

Results

We included 62 eyes from 52 patients, age 23.8±7.3 years. Pre- and post-treatment BCVA were 0.35±0.24 and 0.19±0.14 logMAR (p<0.001). Pre- and post-treatment anterior mean K of 4 mm zone [AR1] were 48.38±0.49 and 48.35±0.65 (p=0.49), while pre- and post-treatment posterior K were -7.20±0.14 and -7.17±0.15 (p=0.56). Pre- and post-treatment 4 mm zone anterior corneal topographic astigmatism [AR2] were 3.74±0.21 and 3.89±0.38 (p=0.36) and posterior corneal astigmatism were -0.80±0.08 and -0.80±0.06 (p=0.49). Pre- and post-treatment posterior float values were 55.62±2.08 and 57.11±3.03 (p=0.34).

Conclusion

Biomechanical changes caused by keratoconus induce curvature changes in both the anterior and posterior corneal surface. Despite the tailored and targeted nature of our treatment protocol, in which the inferior part of the cornea receives most of the UVA energy, it seems it can effectively stabilize both the anterior and posterior corneal surfaces, while also improving vision.