Shot File Assisted Ex Vivo Eccentric Keratoconic Eye Model Recipient For Stromal Lenticule Addition Keratoplasty (Slak)

This study aims to develop a new Keratoconus (KC) Model using the MEL80 Excimer laser to better understand and treat this eye condition, with potential application in Small Incision Lenticule Keratoplasty (SLAK) procedures. By applying principles from a previously published interim study and analyzing data from real keratoconus patients, we hope to create a model that closely mimics the shape of a keratoconic cornea. While it won't replicate the biomechanical properties of corneal ectasia, it will offer valuable insights into how to improve treatments for those affected by keratoconus.

Ophthalmology Clinic, Department of Medicine and Aging Sciences, University "G. D'Annunzio" of Chieti-Pescara, Italy. Department of Medicine and Aging Science, Center for Advanced Studies and Technology-CAST, University G. d’Annunzio of Chieti-Pescara, Italy. Lebanese University: Genomic Surveillance and Biotherapy GSBT, Faculty of Sciences, RasMaska, and Doctoral School of Sciences and Technology, Hadath, Lebanon. Department of Translational Medicine, University of Ferrara, Ferrara, Italy.

Donor corneo-scleral discs were mounted on an artificial anterior chamber, and the epithelium was removed. After tomographic examination, excimer laser ablation reshaped the corneal surfaces to mimic keratoconus by sequentially applying two ablation patterns to the anterior and posterior surfaces. The anterior pattern created a decentered protrusion, while the posterior pattern reduced corneal thickness at the protrusion site. Markings ensured uniformity and precision in the stromal ablations. Tomographic and aberrometric analyses using AS-OCT evaluated corneal surface changes, including pachymetry, keratometry, elevation, curvature symmetry, and aberrations. Statistical tests were carried out using R-based JAMOVI software.

Postoperative corneal apex thickness significantly decreased to 435.2 µm (p=0.006), with a mean difference of 31.5 µm. Anterior Kmax increased to 58.023 D, and posterior Kmax decreased to -9.555 D, with significant changes (p=0.002). AvgK value significantly increased to 45.825 D (p<0.001). SIF value increased significantly to 3.759 (p<0.001). Inferior peripheral curvature significantly decreased to 7.233 mm (p=0.002), while superior peripheral curvature increased to 8.166 mm (p=0.027) and Q-value to -1.337 (p=0.06). ΔZFMax and ΔZBMax showed highly significant increases (p<0.001). Significant increases were also noted for RMS/A (p=0.037) and coma (p<0.001), while no significant changes were observed in spherical aberration and astigmatism.

The developed Keratoconus (KC) Model using the MEL80 Excimer laser effectively mimics the shape of a keratoconic cornea and provides valuable insights for improving treatments for keratoconus patients. The model demonstrated significant changes in corneal parameters, supporting its potential as a useful tool for understanding and treating keratoconus. Additionally, this KC Model could be valid for the Small Incision Lenticule Keratoplasty (SLAK) procedure, showing promise for its application in managing keratoconus. Further studies are recommended to confirm these findings and explore the model's full potential in clinical settings.