Deep Stromal Opacity After Corneal Cross-linking

Purpose: To describe 3 cases with deep corneal stromal opacity that occurred several months after corneal cross-linking. Methods: A 36-year-old man, a 19-year-old man, and a 14-year-old girl underwent corneal cross-linking for their progressive keratoconus. Corneal cross-linking was performed according to the Dresden protocol. The corneal epithelium was ablated using an excimer laser in 2 cases and manually in 1 case. After 30 minutes of riboflavin presoaking, hypotonic riboflavin solution was applied until the corneal stroma swelled, after which the eyes were exposed to ultraviolet irradiation. Slit-lamp microscopy findings, uncorrected visual acuity, best-corrected visual acuity, manifest refraction, intraocular pressure, and corneal endothelial cell counts were evaluated, and corneal topography with Scheimpflug imaging was performed. Results: In all cases, the epithelium healed without delay. All eyes showed mild stromal infiltration a few days after the procedure; however, the inflammation was resolved within 1 week. The corneal stroma revealed no opacity up to 1 month after the procedure. A deep stromal opacity that extended to the inferior paracentral area developed after a few months and remained for 6 months to 1 year. Because the opacity was not on the visual axis, the visual acuity was not involved. Conclusions: Deep stromal opacity developed several months after uneventful corneal cross-linking. Postoperative inflammation may play a crucial role in its pathogenesis.