Assessment of choroidal vascularity and thickness after corneal crosslinking treatment in keratoconus

This study assessed the choroidal vascular index (CVI) and choroidal thickness (CT) in individuals with keratoconus following corneal collagen cross-linking (CXL) therapy. Twenty-five eyes of 25 patients who underwent corneal CXL were included in the study. The enhanced depth imaging (EDI) mode of optical coherence tomography (OCT) was used to measure subfoveal, nasal, temporal CT and CVI prior to surgery and in the first week and month following surgery. Subfoveal, nasal, and temporal CT increased dramatically in the first week compared to pre-surgery measurement (p < 0.05). The nasal and temporal CT measured in the first month decreased significantly compared to the first week (p < 0.05), while a decrease in the subfoveal region was not statistically significant (p = 0.35). The subfoveal, nasal, and temporal CT measured at the first month were not different from the preoperative measurements (p > 0.05). There was no significant change in terms of CVI, stromal area, luminal area, or total choroidal area before and after treatment (p > 0.05). CT shows a transient increase during the first week following CXL, which regresses to baseline levels by the first postoperative month. Importantly, choroidal vascular structures including CVI, luminal, and stromal components remain unaffected. These findings suggest that CXL induces a mild and reversible increase in CT without compromising choroidal vascular integrity in the early postoperative period.