Investigation of the biomechanics of blue-light cross-linking on rabbit scleral tissue with different concentrations of riboflavin
ZOU Ying,ZHANG Miao,ZHANG Fengju
Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology and Visual Sciences Key Lab, Beijing 100730, China
Objective This study had two objectives: To evaluate the efficiency of collagen cross-linking (CXL) in rabbit sclera induced by different concentrations of riboflavin and blue light.To find the optimal concentration of riboflavin in scleral cross-linking. Methods In this experimental study, scleral stress-strain measurementswere performed to evaluate the biomechanical efficiency of collagen cross-linking using riboflavin and blue light (460 nm). Ten New Zealand rabbits were randomly divided into Group Ⅰ and Ⅱ. In Group Ⅰ, a 0.1% riboflavin solution was used for the CXL induced by blue light. In Group Ⅱ, a 0.5% riboflavin solution was used. In each group, the right eye was defined as the experimental eye and the left eye was the control. Biomechanical measurements of scleral strips were performed 2 months after CXL using a microcomputer-controlled biomaterial testing device. The focus was on Young′s modulus calculated as σ=Aexp(B×ε) and maximum stress. The data were analyzed by paired sample t-test and two independent sample t-test. Results Scleral specimens from both groups exhibited nonlinear stress-strain behavior with an initially low Young′s modulus that increased gradually under higher stress. It was derived using the equation σ=Aexp(B×ε). The Young′s modulus (Group Ⅰ: t=19.78, P<0.01; Group Ⅱ: t=7.82, P<0.01) and maximum stress (Group Ⅰ: t=4.90, P<0.05; Group Ⅱ: t=4.30, P<0.05) of the sclera increased after CXL. In addition, the scleral strips in Group Ⅰ were stiffer than in Group Ⅱ (Young′s modulus: t=2.52, P<0.05; Maximum stress: t=3.03, P<0.05). Conclusion CXL induced by riboflavin/blue light can significantly enhance the biomechanical strength of rabbit sclera. The 0.1% riboflavin solution had significantly better biomechanical behavior than the 0.5% riboflavin in CXL.
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ZOU Ying,ZHANG Miao,ZHANG Fengju. Investigation of the biomechanics of blue-light cross-linking on rabbit scleral tissue with different concentrations of riboflavin. Chinese Journal of Optometry Ophthalmology and Visual science, 2017, 19(1): 9-13. DOI: DOI:10.3760/cma.j.issn.1674-845X.2017.01.003
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