SS-OCT based ocular biometry and rheological mechanical model for comprehensive analysis of the eye reaction to air-puff stimulus (Conference Presentation)

Abstract

The aim of this study was to develop a comprehensive biomechanical model to predict biomechanical properties of all ocular tissues and to compare the simulations with air-puff swept-source OCT data. We developed a novel rheological model of the whole eye. The cornea and the crystalline lens were modelled as a combination of spring and dashpot(s) to describe their viscoelastic properties. In addition, a mass element was included to model lenticular wobbling after air pulse. Finally, the eye retraction (depending on the fatty and muscle tissues behind the eye globe) was modeled by a parallel combination of a spring and dashpot elements, and a mass component described the weight of the eye. We measured deformation profiles of ocular components of the human eyes in-vivo using long-range SS-OCT instrument integrated with air-puff stimulation, which enables to visualize the dynamics of eye through its entire length and to measure the intraocular distances (SS-OCT ocular biometer). The deformations calculated from the model were fitted to the measured profiles data using Levenberg-Marquardt method. The rheological model allowed for predicting the displacements of the cornea and the crystalline lens (1.25mm and 0.115mm, respectively), the eye retraction (0.28mm) and the axial wobbling of the lens within 40ms. The developed model outcomes match well to experimental data of corneal and lenticular hysteresis curves identifying viscoelastic properties of the ocular tissues In conclusion, the proposed rheological model correctly predicts the effects observed with air-puff SS-OCT ocular biometer and it can be used in future modelling of the whole eye biomechanics.