Relationship between intraocular pressure (IOP) and the intraocular volume (IOV) was obtained for three mechanical models with following problem statements: 1) the eyeball shell is assumed to be ellipsoidal transversal isotropic shell; 2) the corneoscleral shell of the eye is modeled as a conjugated shell consisting of two segments (sclera and cornea); 3) in the third model the coupled fluid-structure interactions in the eye are taken into account.