Epithelial And Graft Remodelling Patterns Following Corneal Allogenic Intrastromal Ring Segment (Cairs) Insertion.

To observe and quantify changes in recipient epithelium and donor ring segment following corneal allogenic intrastromal ring segment (CAIRS) implantation.

Case series.

In 19 eyes of 17 patients with keratoconus, high resolution anterior segment optical coherence tomography (AS-OCT) was utilized to map epithelial thickness prior to CAIRS implantation and both epithelium and graft thicknesses at 1 week, 1 month, and 3 months following implantation. The pattern and magnitude of epithelial thickening and thinning was analyzed via non-parametric Mann-Whitney U-test.

The pattern of epithelial thickening changed significantly within 1 week of CAIRS implantation and stabilized by 3 months. Pre-operatively a typical pattern of epithelial thickening was observed around the base of the cone and compensatory thinning at the apex. The average thinnest location was 38 microns [26,48] and average thickest location of 66 microns [51,75] pre-operatively. By 3 months post-operatively the average thinnest location was 39 microns [26,52] and average thickest location was 72 microns [60,86]. After CAIRS implantation, the magnitude of the thinnest location did not change (p-value 0.400), however, the magnitude of the thickest location increased (p-value 0.012). 

The epithelial compensation pattern changed significantly after CAIRS implantation. The thickest location was found in the space between the corneal apex and the apex of the CAIRS implant. A greater magnitude of epithelial masking was present post-op. Attention to epithelial patterns is crucial for any subsequent excimer ablation and cross-linking.