A mechanical model of ocular bulb vibrations and implications for acoustic tonometry

In this study, we propose a comprehensive mechanical model of ocular bulb vibrations and discuss its implications for acoustic tonometry. The model describes the eye wall as a spherical, pre-stressed elastic shell containing a viscoelastic material and accounts for the interaction between the elastic corneoscleral shell and the viscoelastic vitreous humor. We investigate the natural frequencies of the system and the corresponding vibration modes, expanding the solution in terms of scalar and vector spherical harmonics. Our findings reveal the significant role of intraocular pressure (IOP) and ocular rigidity in influencing vibration frequencies, while the vitreous rheological properties primarily affect damping. This study contributes to the understanding of the mechanical behavior of the eye under dynamic conditions, with potential implications for non-contact intraocular pressure measurement techniques such as acoustic tonometry. The model can also be relevant for other ocular pathological conditions, such as traumatic retinal detachment, which are believed to be influenced by the dynamic behavior of the eye.