Résumé
Purpose: keratoconus is a bilateral, non-inflammatory corneal disorder characterized by progressive thinning and deformation of cornea, causing irregular astigmatism and visual impairment. This study aims to assess the impact of intracorneal ring segments (ICRS) on aberrometric parameters and their relationship with refractive and keratometric modifications in keratoconic eyes. We explore the potential benefits of ICRS implantation in improving visual outcomes and correcting corneal irregularities through optical aberrations. Design: monocentric, retrospective, non randomized study. Methods: patients with stable keratoconus who underwent ICRS implantation were retrospectively analyzed. Twenty-two eyes were screened, with 12 meeting the inclusion criteria. Preoperative and postoperative assessments, conducted from 3 to 9 months postoperatively, included best-corrected visual acuity (BCVA), refractive parameters (spherical power, cylinder power, spherical equivalent), keratometric measurements (steep, flat, maximal meridians and asphericity factor (Q)), and aberrometric parameters (corneal high-order aberrations (HOA)). Correlation analyses were conducted to investigate the relationships between these different parameters. Results: ICRS implantation led to significant improvements in visual outcomes. BCVA demonstrated a significant mean gain of two lines (P=0.02). Cylinder power decreased significantly by over 50% (p=0.04), while reduction in spherical equivalent and spherical power were not statistically significant (p>0.05). The steepest meridian keratometry (K2) demonstrated a significant trend reduction from 53.75±6.02D to 49.49±5.42D (P=0.08), as did maximal range keratometry (K2-K1) from 5.86±3.30D to 3.62±2.01D (P=0.06). Corneal asphericity (Q) showed a statistically significant reduction from -1.02±0.60 to 0.41±0.68 (P=0.03). Total high-order aberrations displayed a trend towards reduction in vertical and horizontal coma patterns, respectively, from preoperative: -0.39±0.29μm to postoperative: -0.32±0.31μm (P=0.09), and preoperative: -0.13±0.25μm to postoperative: -0.05±0.19μm (P=.08).Correlation analyses revealed robust connections between HOA reduction and BCVA improvement (R=0.61; P=0.42), keratometry flattening (R=0.82; P<0.01), and reduction of corneal prolateness (R=0.94; P=0.01). Conclusion: ICRS allow for significant improvements in vision by reducing irregular astigmatism and enhancing visual quality. ICRS also contribute to flattening and regularization of the central cornea, leading to improved keratometric parameters that are strongly correlated with reduced optical aberrations and visual acuity gain. Despite certain limitations, these results support ICRS as a recognized treatment option for corneal irregularities in patients with keratoconus.