Central toxic keratopathy following corneal collagen cross-linking

Abstract

Dear Editor, Corneal collagen cross-linking (CXL) is a revolutionary procedure to halt keratoconus (KCN) progression, but it is not complication-free. Infectious keratitis, persistent epithelial defects, corneal edema, or severe melt have been reported after CXL (1). Most of the complications can be managed easily; some may lead to severe visual loss, such as central toxic keratopathy (CTK).Herein, we present six eyes of four patients that underwent CXL for progressive KCN elsewhere and, then, were referred to Dokuz Eylül University, Department of Ophthalmology with findings consistent with CTK (Table 1). Patients underwent detailed ophthalmological examination including corrected distance visual acuity (CDVA) on Snellen chart, slit-lamp examination, Scheimpflug corneal tomography (Pentacam, Oculus®, Germany), and specular microscopy (CellCheck, Konan®, United States). The study adhered to the tenets of Declaration of Helsinki.All patients complained of decreased vision after CXL with significant hyperopic shift. Slit-lamp examination revealed central corneal haze or scarring, vertical striae with indistinct margins, thinning and flattening, and clear peripheral cornea. No epithelial defect, epithelial laxity, staining patterns, stromal, or epithelial edema was detected. In Case 1, confocal microscopy showed acellular stroma, striations, and thick collagen bundles (Figs. 1a-c), and specular microscopy