Physics

Keratometer

Visual acuity

Ophthalmology

Optics

Astronomy

Astigmatism

Surgery

Meridian (astronomy)

Trephine

Cornea

Corneal collagen cross-linking

Corneal topography

Keratoconus

Medicine

Journal of Refractive Surgery

PURPOSE: To describe a new technique for the treatment of keratoconus using corneal allogenic intrastromal ring segments (CAIRS). METHODS: CAIRS trephined from donor cornea using a double-bladed trephine were implanted into mid-depth femtosecond laser–dissected channels in the cornea of patients with keratoconus in the 6.5-mm optic zone, followed by accelerated corneal cross-linking (A-CXL)—either conventional or contact lens–assisted CXL (A-CACXL), depending on minimum corneal thickness. RESULTS: Twenty patients (24 eyes) with stage 1 to 4 keratoconus (Amsler–Krumeich grading) were included. Mean follow-up was 11.58 ± 3.6 months (range: 6 to 18 months). There was significant improvement in uncorrected (2.79 ± 2.65 lines; range: 0 to 8 lines) and corrected (1.29 ± 1.33 lines; range: 0 to 5 lines) distance visual acuity, spherical equivalent, simulated maximum keratometry, steepest keratometry, topographic astigmatism, anterior and posterior best fit spheres, and mean power in the 3- and 5-mm zones. No eye showed progression during the entire follow-up. All segments remained well positioned and no segment-induced complications were seen. No other major intraoperative or postoperative complications were observed. CONCLUSIONS: This pilot study indicates that CAIRS with CXL may be a simple, safe, and effective option for treating keratoconus. Further studies are recommended to determine long-term outcomes. [ J Refract Surg. 2018;34(5):296–303.]

Corneal Allogenic Intrastromal Ring Segments (CAIRS) Combined With Corneal Cross-linking for Keratoconus