Optical coherence tomography and texture analysis: Non-invasive monitoring of tissue responses to glaucoma implants
AuthorGossage, Kirk William
AdvisorBarton, Jennifer K.
MetadataShow full item record
PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
AbstractGlaucoma is a set of diseases that cause optic nerve damage and visual field loss. The most important risk factor for the development of glaucoma is elevated intraocular pressure. One approach used to alleviate the pressure increase is to surgically install glaucoma implants. Optical coherence tomography (OCT) is an imaging modality capable of acquiring cross-sectional images of tissue using back-reflected light. The images have a resolution of 10-15μm, and are thus best suited for visualizing tissue layers and structures. OCT images of some tissue types have few or no features in this size range but display a characteristic repetitive structure due to speckle. The purpose of this research was to show that OCT is capable of visualizing tissue changes, such as those associated with a healing response to glaucoma implants. A new OCT handheld probe was developed to facilitate in vivo imaging in rabbit eye studies. The OCT probe consisted of a mechanical scaffold designed to allow the imaging fiber to be held in a fixed position with respect to the rabbit eye, with minimal anesthesia. A piezo-electric lateral scanning device allowed the imaging fiber to be scanned across the tissue so that 2-D images may be acquired. Preliminary analysis of OCT images of two types of glaucoma implants indicates that OCT can visualize the development of fibrous encapsulation of the implant, tissue erosion and tube position in the anterior chamber. The application of statistical and spectral texture analysis techniques was investigated for differentiating tissue types based on the structural and speckle content in OCT images. Excellent correct classification rates were obtained for images of tissues and tissue phantoms that had slight visual differences and reasonable rates were obtained with nearly identical-appearing images of tissues and tissue phantoms. This study shows that OCT is capable of visualizing structural changes, associated with the healing response, on the order of tens to hundreds of microns. OCT also shows promise in being able to detect sub-resolution tissue healing response changes, by quantifying the changes in the speckle seen in OCT images, using texture analysis.
Degree ProgramGraduate College