Comparison of Visual and Topographic Outcomes Between Deep Anterior Lamellar Keratoplasty and Corneal Allogenic Intrastromal Ring Segment Implantation in Advanced Keratoconus: A Preliminary Study.

PURPOSE: To compare the visual, refractive, and topographic outcomes of deep anterior lamellar keratoplasty (DALK) and Corneal Allogenic Intrastromal Ring Segment (CAIRS) implantation in eyes with advanced keratoconus.

METHODS

This retrospective comparative study included 52 eyes of 52 patients with advanced keratoconus (Kmax > 58.0 D along with poor contact lens tolerance and inadequate spectacle-corrected distance visual acuity) who underwent either DALK (n = 26) or CAIRS implantation (n = 26). Preoperative and postoperative uncorrected and best-corrected visual acuity (UCVA, BCVA), spherical equivalent, keratometric values, and corneal higher-order aberrations were analyzed. All patients completed a minimum follow-up of 6 months after CAIRS implantation or 6 months after suture removal after DALK.

RESULTS

Both procedures resulted in significant improvements in UCVA, BCVA, spherical equivalent, and keratometric values (all P < 0.001). Postoperative BCVA was significantly better in the DALK group (P = 0.027), whereas postoperative UCVA, refractive parameters, and keratometric measurements were comparable between groups (all P > 0.05). No significant differences in postoperative aberration parameters were detected between groups.

CONCLUSIONS

This study demonstrated that both CAIRS and DALK resulted in significant improvements in visual acuity, refractive outcomes, keratometric values, and aberrometric parameters in advanced keratoconus. CAIRS may have a role as an intermediate option in carefully selected cases before keratoplasty. Larger prospective studies with long-term follow-up are warranted.