The effects of different riboflavin concentrations and infiltration times on rabbit scleral crosslinking.

To explore the photosensitizer content, diffusion depth and crosslinking effects in rabbit sclera with different riboflavin (Rf) infiltration times and concentrations. For the fluorescence study, rabbit eyes were infiltrated in Rf solutions of different concentrations for different durations on the sclera. The scleral Rf infiltration depth and fluorescence intensity were analyzed with an LSM710 confocal microscope, and the Rf content was detected by the absorbance of the sclera homogenate supernatant. Ultraviolet A was used to perform scleral crosslinking (SXL). The effect of SXL was evaluated using uniaxial tensile testing and enzymatic resistance testing, and the biological safety was evaluated using HE and TUNEL staining. Transmission electron microscopy (TEM) observation was used to clarify the change in collagen fiber diameter. Rf quickly infiltrated the full scleral thickness at 0.05 % concentration for 5 min. The scleral Rf content was not statistically different after infiltration with 0.5 % Rf for 5 min or 10 min. The scleral tissues of the 0.1 % Rf-30 min group and the 0.5 % Rf-5 min group were digested completely within 22.7 ± 1.9 h and 25.3 ± 5.5 h, respectively. At 10 % strain, the Young's modulus of the 0.5 % Rf-5 min group was significantly higher than the control group (P = 0.0004). No obvious structural damage was observed in the retina or sclera, and the diameter of collagen fibers in the outer and middle scleral layers increased significantly after SXL. Ultimately, Rf infiltration at a concentration of 0.5 % for 5 min helped to shorten operation time and improve SXL effects.