A study on the fluid-structure interaction and biomechanical effects of the eye on iop measurements using a vibration based tonometry
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2010
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Abstract
Glaucoma, the second leading cause of blindness worldwide, is a group of diseases of the optic nerve that is generally characterized by an increase of intraocular pressure (IOP). Early diagnosis and treatments through eye exams may prevent the visual damage from glaucoma. Monitoring the IOP is one of the most common ways for detecting the progression of this disease as high IOP can lead to glaucoma and vision loss. This study investigates the correlation between IOP and vibration characteristics of the eye to examine the potential of measurements of variation in these characteristics as an estimate in changing IOP. In this regards, a finite element model of the eye subjected to vibration was developed. This model led to solve a problem of fluid-structural interactions of a generally spherically shaped shell system. The structural dynamic effects due to change in pressure of the fluid were also examined. The finite element model was verified by comparing its vibrational characteristics with the results of an experimental modal analysis on an elastic spherical shell filled with water. The numerical model was then used to analyze a finite element model of a pig eye. The results of the numerical model were supported by performing a series of experimental modal analysis (EMA) on the enucleated pig eyes. The comparisons between the finite element model and the experimental results showed that an increase in the IOP results in an increase the natural frequencies of the eye. The influences of different biomechanical properties of the eye were also investigated through a statistical analysis on the pig eyes and a design of experiment analysis on the finite element model of the eye. A non-contact vibration based tonometery was designed based on the correlations between IOP and natural frequencies of the eye. The applicability of the design was examined through a finite element analysis. The eye in the design was excited through an air impulse and the acoustic pressure waves resultant from the vibrations of the eye were recorded through an array of pressure sensors that were located around the front of the eye. Dynamics of the eye were then analyzed through acquiring the frequency contents of the measurements at the sensors. The influences of the different design variables were also investigated through an optimization study.
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Bibliography: p. 134-138
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Citation
Salimi, S. (2010). A study on the fluid-structure interaction and biomechanical effects of the eye on iop measurements using a vibration based tonometry (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/3741