Purpose: Collagenase could be considered as a method for generating animal model of keratoconus. The authors aimed to evaluate the impact of collagenase on the interlamellar cohesive force of rabbit corneas.

Methods: 20 post mortem New Zealand white rabbit corneas were divided into 4 groups: group 1(15 mg/ml collagenase type II with 15% dextran, N=5), group 2(10 mg/ml collagenase type II with 15% dextran, N=5),group 3(5 mg/ml collagenase type II with 15% dextran, N=5) and group 4(the control group,15% dextran, N=5). After removing epithelium and measuring the corneal thickness, 9*4mm corneal strips were incised and interlamellar cohesive force at 50% depth of stroma was measured with a microcomputer-controlled biomaterial testing machine.

Results: The mean interlamellar cohesive force of group 1，group 2,group 3 and group 4 was 0.225 N/mm,0.217 N/mm,0.199 N/mm,and 0.211 N/mm respectively; without statistically significant differences. Light microscopy showed stromal tissue became less tight after collagenase exposure.

Conclusions: Collagenase exposure does not decrease the interlamellar cohesive force in rabbit corneas, indicating that there is no significant effect of collagenase on interlamellar cohesion. Histopathology revealed less tight stroma after collagenase exposure due to its collagen digestion effect.