Comparison of rose bengal-green light scleral crosslinking in rabbit eyes using different infiltration protocols - An Ex Vivo study

Different concentrations and infiltration times of rose bengal (Rb) were assessed for their impact on penetration depth and crosslinking efficacy in rabbit sclera. Fresh rabbit eyes were used. Rb solution with concentrations of 0.1%–0.9% were applied for 5–30 min to infiltrate the sclera. The penetration depth of Rb was observed with confocal microscopy. After infiltration, the sclera was irradiated by green light for crosslinking. The sclera's biomechanical stiffness and the resistance to enzyme digestion post-treatment were evaluated. Histopathological analysis and transmission electron microscopy were performed to observe the morphology. As the infiltration time increased, the penetration depth and the fluorescence intensity of the Rb in sclera increased. After 32 h, 48.6% of the scleral tissue was undissolved in the 0.5% Rb-10min group, followed by the 0.1% Rb-20min group (13.8%) and 0.05% Rb-30min group (7.7%). At 8% strain, the Young's modulus of the 0.05%Rb-30min, the 0.1% Rb-20min and the 0.5% Rb-10min group were respectively 1.77, 2.45 and 3.19 times greater than that of the untreated group. There were no morphological differences between the experimental group and the untreated group. RG-SXL significantly increased the diameter of large collagen fibers in the middle and inner layers of the sclera. Ultimately, 0.5% Rb infiltration for 10 min achieves an appropriate infiltration depth and crosslinking effect, and may thus be a feasible schedule for scleral crosslinking.