Effects of ultraviolet cross-linking on biomechanics of the cornea

Corneal cross-linking is the method of ultraviolet irradiation (370 nm) of cornea with the use of riboflavin. We studied the influence of solutions of isoosmotic riboflavin, riboflavin with dextran, hydroxypropylmethylcellulose riboflavin and ultraviolet irradiation (370 nm, 3 mW/cm2, 30 min) on biomechanical properties of porcine corneas ex vivo. We also studied the impact of ultraviolet irradiation on the cornea without using riboflavin and dextran polymer. Ultraviolet cross-linking with riboflavin solutions caused a significant increase in the Young’s modulus of elasticity from 164 to 198%, and increase in its maximum strength from 181 to 242% comparing to intact control group. There were no significant differences in the studied parameters between two groups where solutions of riboflavin were used. Dextran provided dehydrogenating effect on the cornea and also increased its rigidity. Ultraviolet exposure without riboflavin was to a far lesser degree of resistance to stretching of the cornea and affected its mechanical properties.