Abstract
Purpose :
Changes in the mechanical properties of the sclera increase the susceptibility of glaucomatous damage on the optic disc. This study explores the law of changes in the mechanical properties of the sclera during the development of myopia and glaucoma, and finds the effect of genipin cross-linking on the biomechanical mechanism of the development of myopia and glaucoma.
Methods :
MTS Insight electronic universal tensile testing machine(fig 1) was used to conduct tension test, relaxation test and creep test on the sclera . Obtain multiple biomechanical parameters such as maximum stress, maximum strain, Young's modulus, relaxation modulus, and creep rate. The biomechanical parameters of each group were compared, and the biomechanical changes and similarities and differences of guinea pigs with high myopia, chronic glaucoma models and genipin cross-linking were analyzed.
Results :
The maximum tensile force and maximum stress of the high myopia group were significantly reduced (P<0.001 vs control group), indicating that the high myopia group's sclera's ability to withstand external forces was reduced, and the biomechanical properties of the sclera were weakened. Compared with the control group, the Young's modulus of the guinea pig sclera in the high myopia group became smaller, and showed a decreasing trend with the increase of modeling time, indicating that the strength of the myopic sclera decreased, the compliance increased, and the external force required for the deformation of the sclera tissue became smaller. As shown in Stress–strain curve(fig 2)，he maximum tensile force and maximum stress of the sclera in the glaucoma group were lower than those in the control group, and the Young's modulus was greater than that in the control group. This change was consistent with the results of the relaxation test, suggesting that the hardness of the sclera in the glaucoma group increased and its compliance decreased.
Conclusions :
The creep rate and Young's modulus of the sclera in myopic guinea pigs and glaucoma guinea pigs showed negative correlation changes, however the tensile strength decreased. Genipin cross-linking was able to effectively improve the biomechanical properties of the sclera in both models. After cross-linking with genipin, the tensile strength is significantly enhanced, which can effectively inhibit the expansion of the sclera during high myopia or glaucoma.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.