Development of Optical Coherence Tomography Systems for Ophthalmic Imaging and Intrasurgical Guidance

Abstract

<p>Ophthalmic microsurgery is one of the most commonly performed surgical procedures in the world and it necessitates precise three-dimensional manipulation of tissue at sub-millimeter spatial scales. As a result, ophthalmic surgeons require an operating microscope to perform surgery and to asses alterations to the tissue. Unfortunately, modern operating microscopes provide a limited en face perspective of the three-dimensional surgical field, and surgeons must infer depth information using stereoscopy and cannot directly visualize sub-surface anatomy. These limitations may compromise the surgeon’s ability to maneuver instruments axially and to comprehensively evaluate the three-dimensional tissue structure. </p><p>Optical coherence tomography (OCT) is a non-contact volumetric imaging modality that is well suited to image the anterior and posterior human eye in vivo. The success of OCT in clinical ophthalmology motivated the development of intraoperative OCT to overcome the limitations of the operating microscope for ophthalmic surgery. However, current intraoperative OCT systems either require pauses in surgery for imaging or are restricted to cross-sectional imaging during surgery, thereby preventing OCT imaging of live surgery that extends over three-dimensional space. </p><p>This dissertation describes the design, development, and assessment of novel technologies for ophthalmic OCT imaging and intrasurgical guidance. These technologies seek to address challenges associated with translating a biomedical imaging device to the human operating suite and to improve upon current surgical visualization methods. We first describe eye tracking technologies designed to compensate for undesired subject motion during retinal and anterior eye OCT imaging. Next, we present a novel optical design for OCT retinal imaging, demonstrate its use for pediatric imaging, and discuss its advantages compared to conventional OCT retinal scanners. We then present the first 4D (volumetric imaging over time) intraoperative OCT system capable of imaging human ophthalmic surgery at up to 3 volumes/second. We report the results of a clinical study in which 4D intraoperative OCT was successfully used in >150 human eye surgeries. Next, we describe the optimization of an ultrahigh-speed OCT system using optical amplification and present a novel OCT scanning method designed for 4D imaging. Finally, we present the preliminary design of a second-generation 4D intraoperative OCT system capable of imaging surgical maneuvers at 15 volumes/second.</p>