Study On Mechanical Property Of Rabbit Eyeball Under Inner Pressure

In this paper, biomechanics tests were performed on the pure-bred New Zealand white rabbits' eyeballs in order to explore the changes of ocular rigidity with inner pressure and relative factors and reveal the biomechanical properties of eyeball. At the same time, the influences of different factors (intraocular pressure (IOP), corneal central thickness (CCT), eyeball volume, etc.) on the biomechanics indicators were studied. The results could provide valuable reference in ophthalmic surgery and myopia, glaucoma and other important eye disease.Based on the pure-bred New Zealand white rabbits, seepage test and circulation test in vitro were carried out using INSTRON5544 testing machine. The relationship of New Zealand white rabbits'eyeball rigidity with inner pressure,eyeball volume,axial length and CCT were detected. The main work was concluded as follows:1,Experimental research demonstrated that the relationship of eyeball volume ratio with IOP showed an exponential change in normal physiological IOP range,and obtained corresponding exponentially fitted formula under various age groups as well as all coefficients in the formula: (2,Experimental research demonstrated that ocular overall rigidity K1 grow with IOP increasing: K 1 = 0. 02853×e(14I3O.5P46)+6.678,while ocular rigidity decay with age increasing, and the results also showed that ocular rigidity showed an exponential decay with eyeball volume and axial length increasing.3,Experimental results showed that the intraocular pressure will depress along with the diminishing of corneal thickness , and the relation approximated linear: y = 0. 27279x+70.1125.The property of rabbit eyeball which was under inner pressure was studied by the use of the relevant theoretical knowledge. According to the theoretical derivation, we got the stress, strain and displacement formula of the cornea and sclera at any point. The part of theoretical analysis described the eye movement in a certain situation of internal pressure from the perspective of mathematics and mechanics, and this provided some basis for glaucoma research; myopia treatment, and post-operative eye protection.On the basis of whole measurement of eyeball, the ANSYS Finite model of three- dimension shell was established. And the imitating results in the elastic statements of strength and strain were got. It was found that great presence of stress and deformation existed near the posterior pole of the eye from the result of Simulation. It was Consistent with the high-tension glaucoma and seepage phenomena of optic nerve found in researches. Comparison of the strain nephogram of normal eyes and myopic model in the same internal pressure showed that the overall deformation of myopia was greater than the normal eye, while the overall stiffness and the ability to resist deformation were smaller.In this paper, the biomechanical model of eyeball under inner pressure was set up by experimental research, theoretical analysis and ANSYS finite element simulation. This may provide valuable evidence for the security in curing myopia with laser and have a certain practical significance.