Résumé
Purpose: to analyze morphological and cellular changes induced by intracorneal ring segment implantation in keratoconus patients.Setting: department of ophthalmology, University Hospital Center, Montpellier, France.Design: prospective, non-comparative, interventional case series.Methods: keratoconus patient having ICRS surgery were examined preoperatively, 8 days, 1 month and 3 months postoperatively. Each visit included biomicroscopy, best corrected visual acuity (BCVA), spherical equivalent (ES), corneal topography: anterior flat (K1) and steep (K2) keratometry, maximal keratometry (Kmax), thinnest pachymetry, epithelial mapping in anterior segment optical coherence tomography (AS-OCT), and main outcomes: cellular density and morphological description using in vivo confocal microscopy (IVCM). 2 zones were analyzed: apical cornea and a ‘target area’ adjacent to the inner segment side.Results: 5 eyes from 5 patients were included in the analysis. 3 months postoperatively, mean epithelial basal cells density in the target area increased by +302.2 cells/mm² ± 181.74 (p=0.021). Mean anterior stromal keratocytes density in the target area increased by +34.8 ± 16.45 cells/mm² (p=0.009). Cellular densities in the apical cornea remained unchanged. Channel lamellar deposits and peri-segmental fibrosis were observed in respectively 5 (100%) and 4 (80%) patients. Epithelial pachymetry in the target zone thickened postoperatively by +5.58 ± 1.46 µm (p=0.001). Conclusion: epithelial basal cells and anterior stromal keratocytes densities were significantly increased in the inner zone adjacent to the segment, 3 months after ICRS implantation in keratoconus patients. This cellular activation likely plays a part in ICRS refractive results and seems to be correlated to BCVA improvement.