ESCRS - PP14.06 - Analysis Of Biomechanical Response After Corneal Crosslinking With Different Fluence Levels

Analysis Of Biomechanical Response After Corneal Crosslinking With Different Fluence Levels

Published 2023 - 41st Congress of the ESCRS

Reference: PP14.06 | Type: Free paper | DOI: 10.82333/9gz7-rh86

Authors: Sophia Anna Reifeltshammer* 1 , Isaak Fischinger 2 , Theo Seiler 3 , Malavika Nambiar 4 , Maria Komninou 4 , Philippe Büchler 5 , Jascha Wendelstein 6 , Matthias Bolz 1

1Department of Ophthalmology and Optometry,Kepler University Clinic,Linz,Austria;Johannes Kepler University,Linz,Austria, 2Augentagesklinik Spreebogen,Berlin,Germany;Department of Ophthalmology and Optometry,Kepler University Clinic,Linz,Austria;Johannes Kepler University,Linz,Austria, 3Institute for Refractive and Ophthalmic Surgery (IROC),Zurich,Switzerland;Department of Ophthalmology and Optometry,University Clinic Düsseldorf,Düsseldorf,Germany;Department of Ophthalmology and Optometry,Inselspital (University Hospital) Bern,Bern,Switzerland, 4ARTORG Center for Biomedical Engineering Research,University of Bern,Bern,Switzerland;Graduate School for Cellular and Biomedical Sciences,University of Bern,Bern,Switzerland, 5ARTORG Center for Biomedical Engineering Research,University of Bern,Bern,Switzerland;ARTORG Center for Biomedical Engineering Research,University of Bern,Bern,Switzerland, 6Department of Ophthalmology and Optometry,Kepler University Clinic,Linz,Austria;Johannes Kepler University,Linz,Austria;Institute for Refractive and Ophthalmic Surgery (IROC),Zurich,Switzerland

Purpose

To evaluate corneal stiffening of porcine corneas induced by corneal crosslinking (CXL) with constant irradiance as a function of total fluence.

Setting

Department of Opthalmology and Optometry, Johannes Kepler University, Linz

Methods

Ninety corneas from freshly enucleated porcine eyes were divided into five groups of 18 each. Group 1 to 4 underwent epi-off CXL using a dextran-based riboflavin solution and an irradiance of 18mW/cm2, group 5 served as the control group. Groups 1 to 4 were treated with a total fluence of 20 J/cm², 15 J/cm², 10.8 J/cm² and 5.4 J/cm², respectively. Thereafter, biomechanical measurements were performed on 5 mm wide and 6 mm long strips using an uniaxial material tester. Pachymetry measurements were performed on each cornea.

Results

At 10% strain, the stress was 75%, 56%, 53% and 31% higher in groups 1 to 4 respectively compared to the control group. The Young’s modulus was 2.84MPa for group 1, 2.53 MPa for group 2, 2.47 MPa for group 3, 2.12MPa for group 4 and 1.62MPa for the control group. The difference between group 1 to 4 and the control group 5 were statistically significant (p=<0.001; p=<0.001; p=<0.001; p=0.021). In addition, group 1 showed significant more stiffening than group 4 (p=<0.001), no other significant differences were found. Pachymetry measurements revealed no statistically significant differences among the five groups.

Conclusions

Additional mechanical stiffening can be achieved by increasing the fluence of the CXL. There was no threshold detected up to 20J/cm2. A higher fluence could compensate the weaker effect of accelerated or epi-on CXL procedures.