Graduation Year
2022
Document Type
Dissertation
Degree
Ph.D.
Degree Name
Doctor of Philosophy (Ph.D.)
Degree Granting Department
Biomedical Engineering
Major Professor
Christopher Passaglia, Ph.D.
Committee Member
Robert Frisina, Ph.D.
Committee Member
Radouil Tzekov, Ph.D.
Committee Member
Mark Jaroszeski, Ph.D.
Committee Member
William Lee, Ph.D.
Keywords
Eye-pump, Glaucoma, Optic Nerve Recordings, Outflow Facility, Visco-elastic
Abstract
Vision is dependent on the proper functioning of many intricate components of the eye. Aqueous humor dynamics function to keep the eye inflated at the right pressures and nourish avascular tissue in the eye while properties of the corneoscleral shell dictate how dynamic changes in volume and pressure affect tissue at the optic nerve head. Retinal ganglion cells exit the globe at the optic nerve head and carry all of the visual information to the brain for perception of visual stimulus. In this dissertation, we aim to present a lumped parameter model of the eye that can accurately describe the how the eye responds to aqueous humor perturbations, specifically we aim to characterize the viscoelastic properties of the globe wall. We aim to use this model to gain insight on outflow facility measurements and propose improvements where needed to allow for outflow facility to be measured in the awake rat. A small portable pump is designed specifically to measure outflow facility in the awake rat and validated in anesthetized and awake settings. Furthermore, we record diurnal fluctuation in outflow facility that match and help explain diurnal fluctuations seen in IOP. This device also allows for precise control over IOP and can be used to induce hypertensive models of glaucoma in awake rats. While multiple ERG paradigms have been developed to assess retinal ganglion cell functioning, the pursuit for a more direct measure of retinal ganglion cell health motivated out exploration of Light evoked compound action potentials. We implement a multimodal gaussian fitting analysis on dark adapted and light adapted ganzfeld flash induced CAPs. Positive correlations between light intensity and peak amplitudes and negative correlations between light intensity and both peak latency and peak width were found.
Scholar Commons Citation
Mohamed, Youssef, "Aqueous Humor Dynamics and Compound Action Potentials in the Anesthetized and Conscious Freely Moving Rat" (2022). USF Tampa Graduate Theses and Dissertations.
https://digitalcommons.usf.edu/etd/9419
