Epithelium-On Cxl Provides A Similar Biomechanical Effect As Accelerated Epithelium-Off Cxl
Published 2023 - 41st Congress of the ESCRS
Reference: FP02.10 | Type: Free paper | DOI: 10.82333/f06a-sh30
Authors: Nanji Lu* 1 , Emilio Torres 2 , M. Enes Aydemir 2 , Sabine Kling 3 , Nikki Hafezi 2 , Farhad Hafezi 4
1Ophthalmology,University of Antwerp,Antwerp,Belgium;Ophthalmology,ELZA Institute,Dietikon,Switzerland, 2Ophthalmology,ELZA Institute,Dietikon,Switzerland, 3ETH,Zurich,Switzerland, 4Ophthalmology,ELZA Institute,Dietikon,Switzerland;Ocular Cell Biology Laboratory,University of Zurich,Zurich,Switzerland
Purpose
Epithelium-on corneal cross-linking (epi-on CXL) comes with several apparent advantages including a reduced risk of infection and rapid recovery. Until recently, epi-on CXL protocols either showed insufficient efficacy or required additional technology such as iontophoresis or additional oxygen. Here, we present the results of a new epi-on CXL protocol without iontophoresis and without additional oxygen, with a stiffening effect similar to the broadly used 10 min @ 9 mW/cm² epi-off CXL.
Setting
ELZA Institute, Dietikon, Switzerland
Methods
150 porcine eyes were assigned equally into 3 study groups: epi-on, epi-off, and untreated controls. A manual abrasion was performed in the epi-off CXL group. Epi-on and control groups: a penetration enhancer solution was applied to the corneal surface before soaking with 0.1% hypo-osmolar riboflavin solution without a carrier. In the epi-off group, the same riboflavin solution was applied directly. Epi-on and epi-off groups were irradiated at 365 nm UV-A light using. In the epi-on group, 18 mW/cm² pulsed UV-A light was applied for 15 min (fluence 8.1 J/cm²); in the epi-off group, 9 mW/cm² continuous UV-A light for 10 min was applied (5.4 J/cm²). Stress-strain extensiometry was performed to assess changes in corneal biomechanics.
Results
The mean elastic modulus as a function between 5% and 10% of strain was 5.21 ± 1.58 N/mm, 4.95 ± 1.50 N/mm, and 4.01 ± 1.41 N/mm in epi-on, epi-off, and controls, respectively. There were no significant differences in the elastic modulus between epi-on and epi-off groups (P=0.45), but significant differences were found between the two cross-linked groups and controls (P<0.001 and =0.001, respectively).
Conclusions
Our new epi-on CXL protocol provides a stiffening effect similar to the most commonly used epi-off CXL protocol and has the potential to clinically replace the latter. Since it does not require additional technology such as iontophoresis or oxygen application, our epi-on CXL protocol may be particularly suited for slit lamp CXL applications.