Keywords
Abstract
The dynamic tonometer test (air-puff test) is an in-vivo investigative procedure routinely utilized in ophthalmology to estimate the intraocular pressure (IOP). A rapid, localized air jet applied on the anterior surface induces the inward motion of the cornea, which interacts with the aqueous humor — filling the narrow space between cornea and iris — and has a strong influence on corneal dynamics. Potentially, this quick and painless test could be combined with inverse analysis methods to characterize the patient-specific mechanical properties of the human cornea. As a step towards this aim, the present study describes a fluid-structure interaction (FSI) approach based on a simplified geometry to simulate the anterior chamber of the eye undergoing the air-puff test. We regard the cornea as a non-linear, elastic, and isotropic membrane described through an analytical model, discretizing the weakly compressible Newtonian fluid with a mesh-free particle approach. Numerical analyses reveal a marked influence of the fluid on corneal dynamics. Additionally, we investigate the possibility of using the test dynamics to estimate IOP.
References
Simonini I, Pandolfi A. Customized finite element modelling of the human cornea. PLoS One. 2015; 10(6):e0130426.
Sanchez P, Moutsouris K, Pandolfi A. Biomechanical and optical behavior of human corneas before and after photorefractive keratectomy, J Cataract Refr Surg 2014;40(6):905-917.
Ariza-Gracia MA, Zurita JF, Pinero DP, Rodriguez-Matas JF, Calvo B. coupled biomechanical response of the cornea assessed by noncontact tonometry. A simulation study. PLoS One. 2015; 10(3):e0121486
Ariza-Gracia MA, Zurita J, Pinero DP, Calvo B, Rodriguez-Matas JF. Automatized patient-specific methodology for numerical determination of biomechanical corneal response. Ann Biomed Eng.2016;44(5):1753-1772.
Ortilles A, Rodriguez-Matas JF, Ariza-Gracia MA, Pascual G, Calvo B. Why non-contact tonometry tests cannot evaluate the effects of corneal collagen cross-linking. J Refract Surg. 2017;33(3):184-192.
Lanchares E, Del Buey MA, Cristobal JA, Calvo B, Ascaso FJ, Malve M. Computational simulation of scleral buckling surgery for rhegmatogenous retinal detachment: On the effect of the band size on the myopization. J Ophthalmol. 2016;2016:3578617.
Pandolfi A, Fotia G, Manganiello F. Finite element simulations of laser refractive corneal surgery. Eng Comput. 2009;25(1):15-24.
Simonini I, Pandolfi A. The influence of intraocular pressure and air jet pressure on corneal contactless tonometry tests. J Mech Behav Biomed. 2016;58:75-89.
Simonini I, Angelillo M, Pandolfi A. Theoretical and numerical analysis of the corneal air puff test. J Mech Phys Solids. 2016;93:118-134.
Asprone D, Auricchio F, Montanino A, Reali A. A modified finite particle method: Multi-dimensional elasto-statics and dynamics. Int J Numer Meth Eng. 2014;99(1):1-25.