Investigating the effect of different riboflavin concentrations on corneal biomechanical properties in crosslinking.

PURPOSE: To evaluate the corneal crosslinking (CXL) efficacy of riboflavin (RF) at 5 different concentrations (0.1%, 0.25%, 0.5%, 0.75%, and 1.0%) and determine the optimal concentration for maximizing the cornea's biomechanical performance.

SETTING

Department of Ophthalmology, Zhongshan Hospital, Fudan University.

DESIGN

Experimental study.

METHODS

The corneal epithelium was removed from all eyes. In the first part, 0.1% to 1.0% RF solutions were applied to rabbit eyes for 30 minutes, with 20% dextran used as the vehicle for the RF solutions. After application, RF concentration in the cornea and aqueous humor were evaluated. In the second part, after applying different RF solutions, the corneas underwent CXL with 9 mW/cm 2 UV-A light for 10 minutes. Stress-strain curves, Young modulus, and resistance to enzymatic digestion were measured.

RESULTS

107 eyes were used in total. RF concentrations in the cornea were 447.57 ± 28.72 μg/g, 536.51 ± 19.59 μg/g, 885.89 ± 111.77 μg/g, 1280.46 ± 103.86 μg/g, and 1668.68 ± 89.02 μg/g from 0.1% to 1.0% RF solutions, respectively. After CXL, the corneal stress of the other 4 groups was 123%, 147%, 116%, and 69% relative to the 0.1% RF group at 10% strain. Similarly, after CXL with RF solutions at 5 concentrations, the residual corneal dry weights were 0.45 ± 0.08 mg, 0.53 ± 0.03 mg, 0.62 ± 0.07 mg, 0.50 ± 0.04 mg, and 0.35 ± 0.05 mg, respectively.

CONCLUSIONS

The 0.5% RF group achieved the optimal corneal biomechanical performance under controlled experimental conditions, with decreased efficiency as the RF concentration further increased.