Spectral Domain Optical Coherence Tomography System Development for In Vivo Ophthalmic Imaging

Spectral Domain Optical Coherence Tomography System Development for In Vivo Ophthalmic Imaging by Mingtao Zhao Department of Biomedical Engineering Duke University Date:____September 17, 2009____________ Approved: ___________________________ Joseph A. Izatt, Supervisor ___________________________ David J. Brady ___________________________ Vo-Dinh Tuan ___________________________ Adam P. Wax ___________________________ Anthony N. Kuo An abstract of a dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of of Philosophy in the Department of Biomedical Engineering in the Graduate School of Duke University 2009 Copyright by Mingtao Zhao 2009 iv Abstract Since its inception, spectral-domain optical coherence tomography (SDOCT) has become a powerful tool for noninvasive imaging of the human eye. In this manuscript, I describe the development of multiple low-cost, high resolution, real-time SDOCT constructions and imaging techniques optimized for rapid 3D imaging and analysis of the human eye in vivo. I have first derived the relationship of dispersion compensation coefficients in the complex conjugated case in 2006. Phase techniques such as polarization sensitive OCT (PSOCT) and Doppler OCT are described for extracting functional information from SDOCT imaging of the retina. A unique phase unwrapping method is presented to measure the total reflectivity, accumulative retardance, and fast axis orientation of the retinal nerve fiber layer (RNFL). A means to segment the polarization scrambling layer of the retinal pigment epithelium employing single camera sequential scan based PSOCT is shown. As an extension, a synthetic wavelength method will also be introduced for phase unwrapping in cellular imaging. Finally, an algorithm for 3D refraction correction accounting for refraction of OCT light in the cornea is described. 3D refraction correction of volumetric corneal datasets allows for the accurate estimation of corneal optical power, thickness, and wavefront aberrations from the corneal surfaces via Zernike spectrum analysis for clinical usage.