Self-Aligning and Handheld Optical Coherence Tomography for Ophthalmic Imaging

Abstract

Retinal disease can cause permanent blindness in patients of all ages, from birth to late adulthood. Optical coherence tomography (OCT) has revolutionized diagnostics in the retina and become ubiquitous in ophthalmology, bringing three-dimensional imaging of the human retina into the hands of a physician in the matter of seconds. Traditional OCT systems, however, are designed for patients who can readily cooperate with a tabletop device in the eye clinic. This excludes many populations with vision-threatening disease, such as bedbound or sedated patients and preterm infants in the nursery at risk for retinopathy of prematurity. In this dissertation, we seek to advance the state of the art in OCT by developing technologies that can operate in non-traditional settings and visualize previously inaccessible findings in adults and children.First, we explore the capabilities of self-aligning OCT. Systems with integrated robotic control and optical alignment allow far more degrees of freedom than do commercial tabletop systems. We leverage this technology to understand and solve optical limitations of high speed point-scanning OCT systems. We also utilize active tracking to automate imaging of the retina from a multitude of angles, revealing information not seen by conventional OCT scans.Next, we investigate handheld systems that bring OCT directly to the bedside. We show that handheld OCT can be used to image structures in the anterior segment through the sclera, and paired with newly emerging optical clearing methods, can visualize deeper into the eye than previously possible. We also develop a lightweight, high speed handheld retinal imaging probe that can be brought into the intensive care nursery to assess both structural and functional information in the pediatric retina. These findings improve our understanding of treatment of retinopathy of prematurity, as well as our understanding of the disease process itself.Drawing on the successes of these two technologies, we combine the best of both to develop a first of its kind self-aligning handheld OCT probe. This device integrates self-alignment technology into a compact, handheld system to address the need for fast alignment without reliance on highly skilled operators. We develop custom designs for the optics, mechanics, and engine in order to achieve tracking and aiming with five degrees of freedom in a portable system that can be brought back and forth between research and clinical spaces.In summary, this research explores the intersection of self-aligning and handheld OCT systems towards increasing access to untapped knowledge in the anterior and posterior eye. We believe the technologies described in this dissertation will advance the state of the art in ophthalmic imaging and lead to a host of research studies and clinical care improvements in adults, children, and infants that were previously inaccessible.