Toric topographically customized transepithelial, pulsed, very high-fluence, higher energy and higher riboflavin concentration collagen cross-linking in keratoconus

Abstract

Purpose: To report a novel application of toric topographically customized transepithelial collagen cross-linking (CXL) aiming to achieve refractive astigmatic changes in a keratoconic cornea.

Methods: Specially formulated riboflavin transepithelial administration and delivery of high-fluence UVA in a topographically customized pattern was applied in an eye with progressive keratoconus. Visual acuity, cornea clarity, keratometry, topography, and pachymetry with a multitude of modalities, as well as endothelial cell counts were evaluated for >6 months.

Results: Uncorrected distance visual acuity changed from preoperative 20/40 to 20/25 at 6 months. A mean astigmatic reduction of 0.8 D, and significant cornea surface normalization was achieved 6 months postoperatively. There was some mild change in the epithelial distribution, with the treated area having a slight normalization in the average epithelial thickness.

Conclusions: We introduce herein the novel application of a topographically customizable transepithelial CXL in progressive keratoconus in order to achieve an astigmatic refractive effect and ectasia stabilization. This novel technique offers a nonablative and nonincisional approach to treat irregular astigmatism in ectatic cornea with rapid visual rehabilitation.

Keywords: High-fluence cross-linking; KXL II; Keratoconus; Photorefractive intrastromal cross-linking; Topography customizable cross-linking; Toric cross-linking; Transepithelial cross-linking.

Fig. 1

Customized treatment profile employed in the treatment. Left panel: details of the applied customizable pattern and parameters for UVA exposure; right panel: overlay of the pattern on the sagittal curvature map.

Fig. 2

Placido disk topography data showing sagittal curvature maps depicting significant refractive changes along the axis of the customized cross-linking pattern. Panel 1: 1 day preoperatively. Panel 2: 6 months postoperatively. Panel to the right: difference 2–1.

Fig. 3

Scheimpflug imaging data showing a comparison of preoperative versus postoperative data at 6 months depicting significant refractive changes along the axis of the customized cross-linking pattern as well as anterior surface normalization and ectasia arrest.

Fig. 4

Anterior segment OCT imaging pachymetry maps for the cornea (left) and corneal epithelium (right) covering the center of the 6-mm diameter area. Top panel: preoperatively; middle panel: 1-week postoperatively, and bottom panel: 6 months postoperatively.