Six-Month Results of Multiple Femtosecond Laser–Assisted Corneal Allogeneic Ring Segments Implantation: A Case Series

Purpose: To evaluate the short- and mid-term clinical outcomes of corneal allogeneic intrastromal ring segments (CAIRS) and assess their efficacy and safety in keratoconus treatment. Methods: Case series of 79 eyes from 71 patients with keratoconus who underwent femtosecond-assisted CAIRS implantation at the Adolphe de Rothschild Hospital Foundation, Noémie de Rothschild Institute. Preoperative and postoperative examinations were conducted at 3 and 6 months. Anterior segment optical coherence tomography and corneal tomography with aberrometric and pachymetric analyses were performed at each visit. Visual, refractive, and topographic parameters were extracted. Results: Corrected distance visual acuity improved by 1, 2, and 3 lines or more in 33%, 44%, and 52% of cases, respectively. Significant improvements were observed in K1, K2, Km, Kmax, topographic astigmatism, sphere, cylinder, spherical equivalent, total root mean square, higher-order aberrations, vertical coma, and spherical aberrations (all P < 0.01 or P < 0.05). Eleven patients (13.9%) were dissatisfied with their outcomes. In addition, 9 patients (13.65%) experienced a loss in corrected distance visual acuity at 3 months postoperatively (6 eyes lost 1 line, and 3 lost 2 lines), yet remained satisfied with their results because of improved refraction and uncorrected vision. Conclusions: This study is the largest to date evaluating femtosecond-assisted CAIRS implantations and highlights CAIRS as a promising treatment for keratoconus.