Clinical And Biomechanical Outcomes Of Corneal Allogenic Intrastromal Ring Segments (Cairs) In Keratoconus

This study aims to evaluate the visual, refractive, and topographic outcomes and the aberrometric and biomechanical results of CAIRS implantation.

Cornea and Refractive Surgery Department, Instituto de Oftalmología Conde de Valenciana, Mexico City, Mexico.

Prospective, interventional, case series. Keratoconus staging was performed using the Amsler-Krumeich classification. Preoperative and postoperative data at 1 week and 1 month were collected, including uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), refractive parameters (sphere, cylinder, spherical equivalent [SE]), keratometry (Kmax, K1, K2), aberrometric measurements (total RMS, higher-order aberration [HOA] RMS, coma, and spherical aberration), and biomechanical parameters (SP-A1, integrated radius, DA ratio, and SSI).

This study included 25 eyes from 18 keratoconus patients (mean age 35.55±7.53 years, 66% male). Most cases (56%) were stage II, 8% stage I, and 8% post-LASIK ectasia. UCVA improved from 1.31±0.54 to 0.59±0.36 logMAR (p=0.001) and BCVA from 0.44±0.27 to 0.27±0.21 logMAR (p=0.002). Sphere improved from -6.11±4.29D to -1.91±3.56D (p<0.0001), cylinder from -4.74±2.1D to -3.77±1.80D (p=0.0003), and SE from -8.48±4.5D to -3.11±3.71D (p=0.0002). Kmax flattened (51.01±6.52D to 46.67±5.15D, p<0.0001). Aberrometry showed reduced total RMS (p=0.01), coma (p<0.001), and spherical aberration (p<0.001). Biomechanical parameters significantly improved. No postoperative complications were reported.

CAIRS effectively improved visual acuity, refractive parameters, topographic values, aberrations, and biomechanical parameters within one month postoperatively.