Synergistic Effects of Ultraviolet A/Riboflavin and Glucose on Corneal Collagen Cross-linking

PURPOSE: To investigate the possible synergistic effect of ultraviolet A (UVA)/ribofl avin and glucose on corneal collagen cross-linking (CXL) by means of the mechanical properties and thermal shrinkage temperatures. METHODS: Forty rabbits were divided into four groups: control group; UVA/glucose group; UVA/riboflavin group; and UVA/riboflavin/glucose group. After the treatments, the mechanical properties and thermal shrinkage temperatures of the corneal strips were analyzed to determine the CXL effects of corneal collagen induced by different treatments. RESULTS: Compared with the control group and other experimental groups, the UVA/riboflavin/glucose group showed significant alterations of the biomechanical properties. The ultimate stress value for the UVA/riboflavin/glucose group was increased by 120%, ultimate strain decreased by 80%, and Young's modulus increased by 70% relative to the control group. An increase in ultimate stress by 24.5%, a decrease in ultimate strain by 34%, and an increase in Young's modulus by 17.4% were found in the UVA/riboflavin/glucose group compared to the UVA/riboflavin group. A significant increase in thermal shrinkage temperatures was also noted after corneal collagen CXL induced by UVA/riboflavin/glucose relative to other groups. CONCLUSIONS: The combination of glucose and UVA/riboflavin may synergistically induce corneal collagen CXL, resulting in increased mechanical strength of corneal collagen. [J Refract Surg. 2011; 27(3): 216-222.] doi:10.3928/1081597X-20101214-02