Central Toxic Keratopathy After Collagen Cross-Linking: A Case Series

The aim of this study was to report a case series of central toxic keratopathy (CTK) after collagen cross-linking (CXL) in keratoconus.

This is a retrospective case series between January 2020 and September 2021. In this period, CXL was performed for progressive keratoconus in 964 eyes. CXL was performed using the epithelium-off accelerated protocol in all patients with a riboflavin soak time of 20 minutes and a UVA light exposure of 9 mW for 10 minutes using the Avedro KXL (Glaukos Inc, Aliso Viejo, CA) cross-linking system.

Twelve of 964 eyes (1.2%) developed CTK within 1 week of CXL. All patients presented with well-circumscribed, central disciform haze that was broader in the anterior stroma and narrower in the posterior stroma. We noted initial flattening in keratometry up to 3 months post-CXL in these patients, which gradually steepened over 12 months, but did not reach preoperative levels. We also noted exuberant flattening in pachymetry in the first 3 months, which improved over 12 months. There was a statistically significant decrease in pachymetry in patients who developed CTK at 3 and 12 months postoperatively when compared to patients who underwent CXL but did not develop CTK.

Several reports of CTK postrefractive surgery have been described previously. However, the association of CXL in the development of CTK has not been described previously. Here, we elucidated the clinical features of CTK after CXL and how it differs from corneal scarring or haze that occurs post-CXL.