Assessing Safety Of Laser-Induced Refractive Index Change (Liric) In Ex Vivo Porcine Corneas
Published 2026 - 44th Congress of the ESCRS
Reference: POOTH015 | Type: Free paper | DOI: 10.82333/3gyw-9995
Authors: Prof. Dr Stephanie C Joachim* 1 , Mr Rainer Koetter 1 , Dr Pascal Naubereit 2 , Ms Athina Chalkidis 2 , Dr Erika Eskina 1 , Prof. Dr H. Burkhard Dick 1 , Dr Teresa Tsai 1
1Ruhr-University Bochum,Bochum,Germany, 2SCHWIND eye-tech-solutions GmbH,Kleinhostheim,Germany
Purpose
To investigate the influence on inflammation, oxidative stress and angiogenesis of Laser-Induced Refractive Index Change (LIRIC), which is a non-invasive method to correct ametropia by altering the refractive index using a femtosecond laser with a high repetition rate and lower energy.
Setting
Laboratory investigation, Experimental Eye Research Institute at University Eye Hospital, Ruhr-University Bochum, Bochum, Germany.
Methods
LIRIC treatment was applied to the stroma of explanted porcine corneas using a 140 fs-laser with two different pulse energy settings (18 and 25 nJ). Untreated corneas served as controls. OCT analysis for a macroscopic control was performed of all groups (n=10/group). The corneas of all five groups (n=8/group) were examined for altered markers of inflammation (IL1B, IL6), oxidative stress (HIF1A, OGG1, SOD1, SOD2), angiogenesis (VEGF, VEGFC), apoptosis (BAX/BCL2), keratinocytes (KERA), and tight junctions (TJP1). Cornea samples were processed for H&E, Masson, and immunofluorescence staining (n=8/group). In addition, a cytokine array was performed (n=2/group).
Results
HIF1A expression was downregulated in the 25 nJ LIRIC group (p<0.05), while other oxidative stress markers were unaltered. VEGF was downregulated in both LIRIC groups (p<0.05). BAX/BCL2 ratio (apoptosis) was only elevated in 25 nJ LIRIC samples (p<0.05). KERA (keratin) expression was upregulated in the 25 nJ LIRIC group (p<0.05), while TJP1 was unaltered. Area analysis of H&E and Masson stain revealed no differences between LIRIC groups and the control. Also, ZO-1, COL1, and K12 staining were comparable in all groups. 10 cytokines were detachable via array, while e.g., decorin was downregulated after LIRIC, e.g., PIGF2 expression was increased.
Conclusions
LIRIC treatment did not affect the macroscopic structure of the corneas. No inflammation, oxidative stress, or angiogenesis was noted after LIRIC. At higher energy settings, a slight expression of cell death markers was observed. Hence, these results indicate that LIRIC is a promising non-invasive technique with minimal adverse effects on corneal structure and health. Given its potential, further clinical studies are essential to evaluate the long-term outcomes and explore the broader clinical applications.