Optical Coherence Tomography Angiography for Imaging and Analysis of the Choriocapillaris in Late Age-Related Macular Degeneration

Abstract

Age-related macular degeneration (AMD), a progressive disease of the retina and choroid, is a leading cause of vision loss. At present, AMD pathogenesis remains incompletely understood, and approved treatments only exist for certain AMD subtypes. In this thesis, we investigate AMD pathophysiology with a focus on choriocapillaris impairment in macular neovascularization and geographic atrophy, the two subtypes comprising late AMD. The choriocapillaris, the capillary layer of the choroid, is responsible for nourishing the outer retina, including the photoreceptors, and has long been hypothesized to have an important role in AMD development and progression. We contribute to the existing understanding of AMD-associated choriocapillaris impairment by developing and applying optical coherence tomography angiography (OCTA) technology in conjunction with image analysis and disease modeling approaches. Key study results presented in this thesis include: (1) the development of an OCTA-based method for microvascular velocimetry that is compatible with clinical ophthalmic imaging; (2) the demonstration and quantification of choriocapillaris impairment surrounding macular neovascularization; (3) the association of macular neovascularization blood flow speeds with responses to vascular endothelial growth factor inhibitor treatment; (4) the demonstration of choriocapillaris impairment surrounding regions of geographic atrophy; and, (5) the development of a biophysical model describing the spatiotemporal expansion of geographic atrophy, and the integration of this model with spatial statistical methods to enable rigorous assessments of local correlations between choriocapillaris impairment and geographic atrophy growth.