Biomechanical Properties of Experimental Myopia in the Guinea Pig

A lens induce myopia model in 12 healthy guinea pigs was used in this study. For each guinea pig, one eye was selected randomly for myopia model, another served as a paired control. After 45 days, eye became myopic and elongated in myopia model. The alteration of eye volume with intraocular pressure was determined. Cornea and sclera strips were prepared for biomechanical properties measurement through uniaxial tension using Instron 5544 test machine. Our results showed that the ocular rigidity coefficient of myopia model eyeballs was lower than the control ones. Furthermore, under the physiological eye pressure, the elastic modulus of either sclera or cornea decreased significantly as compared to control ones. The ANSYS finite element simulation also confirmed that the maximal shape deformation of eyeball occurred in the polar of the post sclera and the maximal strain in the myopia model eyes was higher than the control ones.