Investigation of the properties of the two-component eyeball model and opportunities to use it for practically estimating the mechanical characteristics of the human eye

Abstract

On the basis of the two-component eyeball model proposed in [1], the loadings of the cornea by a rod and wide stamps with flat, convex and concave bases are investigated and compared. It is shown that for all loading types studied the measured geometric deformation characteristic is, over the physiological range of parameters, determined by the pressure under load and depends on the elastic properties of the eye shell only slightly. The problem of eyeball deformation at a constant volume, which corresponds to the clinical procedure of measuring the intraocular pressure, is considered. The pressure dependence on the applied load is studied. It is shown that for the rod and convex stamp the inclination of the straight line which approximates this dependence over the practically important range of loads, as well as the difference between the pressures under load and before loading, depend on the cornea stiffness weakly but are significantly affected by the stiffness of the scleral segment. On the other hand, for the flat and concave stamps these characteristics substantially depend on both elastic constants. A method of measurements and calculations, which makes it possible to increase the informativeness and reliability of the data obtained in clinics by static tonometry, is proposed.