To determine the interlamellar cohesive strength (ICS) of porcine cornea before and after collagen cross-linking using riboflavin and ultraviolet A (UVA) irradiation.
Corneal flaps, 130 μm thick, were created with a microkeratome. Cross-linking was accomplished with 0.1% riboflavin and UVA irradiation for 30 minutes (3 mW/cm2, 5.4 J/cm2) at a distance of 10 mm. Two experiments were performed. (1) The maximal ICS between corneal flap and the stroma was determined and histological examination was performed. (2) The mean stromal ICS was measured. Untreated eyes served as controls in all experiments.
The mean maximum flap-stroma ICS was 0.088 ± 0.046 N/mm in the experimental group and 0.012 ± 0.004 N/mm in the control group (P = 0.009). In experiment 2, incomplete (2 mm long) corneal flaps were used and the mean stromal ICS was 0.750 ± 0.077 N/mm in the experimental group and 0.338 ± 0.046 N/mm in the control group (P < 0.0001). Histological examination showed an irregular ragged separation of the surface in the stromal margin of the cornea with cross-linking, but a smooth separation surface in the cornea without cross-linking.
Collagen cross-linking activated by riboflavin/UVA increases ICS in porcine corneas.
*School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
†School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, China
‡Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, China.
Reprints: Chuanqing Zhou, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China 200240, China (e-mail: firstname.lastname@example.org).
Supported by the National Natural Science Foundation of China (81171377), National Basic Research Program of China (No. 2011CB707504 and No. 2010CB933903), and “111” project from MOE China (No. B08020); Shanghai Leading Academic Discipline Project, Project Number (S30205).
The authors have no conflicts of interest to disclose.
Received January 13, 2012
Accepted June 15, 2012