Demarcation Line Depth Of Epithelium-On Corneal Cross-Linking Without Iontophoresis And Without Additional Oxygen In Patients With Progressive Keratoconus
Published 2023 - 41st Congress of the ESCRS
Reference: FP02.08 | Type: Free paper | DOI: 10.82333/tppb-s162
Authors: Farhad Hafezi* 1 , Nanji Lu 2 , Enes Aydemir 2 , Shady Awwad 3 , Nikki L. Hafezi 2 , Mark Hillen 2 , Emilio A. Torres-Netto 1
1Ophthalmology,ELZA Institute AG,Dietikon,Switzerland;Ocular Cell Biology Laboratory,University of Zurich,Zurich,Switzerland, 2Ophthalmology,ELZA Institute AG,Dietikon,Switzerland, 3Medical Center,American University of Beirut,Beirut,Lebanon
Purpose
Epithelium-on corneal cross-linking (epi-on CXL) has a number of 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. We have recently presented the laboratory 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.Here, we clinically evaluate the demarcation line depth in epithelium-on corneal cross-linking (CXL) without iontophoresis and additional oxygen.
Setting
Clinical setting (ELZA Institute, Zurich, Switzerland).
Methods
23 eyes of 19 patients with documented progressive keratoconus underwent epithelium-on CXL treatment without iontophoresis or additional oxygen. Briefly, a penetration enhancer solution was applied to the corneal surface before soaking with 0.1% hypo-osmolar riboflavin solution without carrier (Ribo-Ker, EMAGine SA, Zug, Switzerland). The cornea was then irradiated at 365 nm UV-A light using a 18 mW/cm² pulsed UV-A light protocol that was applied for 15 minutes to deliver a fluence of 8.1 J/cm² and a commercially available CXL device (C-eye, EMAGine SA, Zug, Switzerland) The demarcation line depth was assessed at one-month post-treatment using high-resolution anterior segment OCT imaging.
Results
The average depth of the demarcation line at the thinnest point was at 225 µm ± 34 µm (range 148 µm – 274 µm).
Conclusions
Our new epithelium-on CXL treatment does not rely on iontophoresis nor on additional oxygen supply, and showed a demarcation line depth of 225 µm ± 34 µm at one month post CXL. This depth of the demarcation line is comparable to the most commonly used epi-off CXL protocol applying 9 mW/cm² for 10 min (5.4 J fluence), and suggests that the efficacy of the new epi-on approach might be similar to that of commonly used epi-off protocols. By avoiding epithelium removal, this approach may reduce pain and infection risk for patients in the post-operative, potentially offering a safer alternative to epi-off techniques.