Comparative Effects of Riboflavin-UVA and Rose Bengal-Green Light Cross-Linking on Corneal Neovascularization

The purpose of this study was to compare the effects of riboflavin-ultraviolet A (RF/UVA) cross-linking (CXL) and rose bengal-green light (RB/green light) CXL on corneal neovascularization (CNV) in rat eyes.

Forty Wistar albino rats underwent CNV induction by corneal suture placement and were randomized into four groups: control, RF/UVA CXL, RB/green light CXL, and green light alone. Treatments were administered on day 3. Anterior segment (AS) photographs and AS-optical coherence tomography (AS-OCT) images were obtained on days 0, 3, 7, and 14, with days 7 and 14 defined as endpoints. Right corneas were analyzed using immunohistochemistry (IHC) for vascular endothelial growth factor (VEGF), lymphatic vessel endothelial hyaluronan receptor (LYVE-1), and CD68, along with hematoxylin & eosin (H&E) staining and TUNEL assay. Left corneas were evaluated with ELISA for VEGF and CD68 levels.

The least CNV area was observed in the RF/UVA group on days 7 and 14 (P = 0.002 and P < 0.001, respectively). The RB/green light CXL group also demonstrated CNV area than the green light alone group on day 7 (P < 0.001). ELISA revealed significantly lower VEGF levels in all treatment groups compared with controls on day 7, whereas this reduction persisted only in the RF/UVA CXL group on day 14 (P < 0.001 and P = 0.049, respectively). VEGF and LYVE-1 immunostaining were significantly lower in the RF/UVA CXL group compared with the green light group at both time points. CD68 staining was reduced in both CXL groups. TUNEL analysis showed the highest keratocyte apoptotic index in the RF/UVA CXL group, followed by the RB/green light CXL group (both P < 0.001).

Both CXL modalities suppressed inflammation and were effective in reducing hemangiogenesis, and lymphangiogenesis; however, the RF/UVA CXL group demonstrated superior overall efficacy than the RB/green light CXL group.