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Title
Optical Imaging and Characterization of Ophthalmic Tissue and Devices
Abstract
This dissertation details three projects relating to measurement and optical engineering across three structures in the eye: the cornea, the crystalline lens, and the retina. The highly ordered structure of collagen in the cornea means that it has a high amount of birefringence and is a strong candidate for polarization sensitive imaging. Polarization sensitive optical coherence tomography (PS-OCT) imaging was performed on three ex vivo porcine eyes across a range of different intraocular pressures (IOP) to draw conclusions about the connection between polarization state and the biomechanical properties of the cornea. The DOPU measured through the depth of the cornea is correlated to microstructural features observed with multiphoton microscopy. The results of this study suggest that PS-OCT could be a promising tool to study corneal collagen cross-linking.
Cataracts are caused by the breakdown of proteins in the natural crystalline lens of the eye, which causes it to become opaque, limiting visual performance. Cataract removal surgery is a safe and efficient out-patient procedure where the cataract is broken down and removed, and the phakic crystalline lens is replaced by a new pseudophakic intraocular lens (IOL). It is important to have a metric to measure the quality of these IOLs, such as the modulation transfer function (MTF). The two-dimensional MTF can be calculated by taking the Fourier transform of the point spread function (PSF). A PSF-based optical system was designed and tested to measure the through focus MTF of IOLs, showing improved results for non-rotationally symmetric systems compared to a commercial edge spread function (ESF) based system.
Finally, the optical design of the camera arm of a retinal surgical microscope was reverse engineered to implement a new camera into the system. Prototypes made of commercially available optical parts were designed and capable of achieving similar image quality to the original system.
Please email Jini at jini@optics.arizona.edu or Paige at psawyers@arizona.edu for a Zoom link.