High speed handheld instrument for ophthalmic optical coherence tomography

Abstract

Optical coherence tomography (OCT) is a non-contact, high resolution biomedical imaging technique that uses low coherence interferometry to generate cross-sectional images of tissue. OCT has become a standard tool in ophthalmology for imaging the retina to detect or monitor pathologies. Recent research advances in swept source lasers have allowed swept source OCT (SS-OCT) to have 5-50x faster imaging speeds when compared to SD-OCT commercial systems. This thesis describes the design of a handheld SS-OCT instrument to screen for retinal diseases. Many retinal diseases are asymptomatic in their early stages and remain undetected until they advance to cause irreversible vision loss. Early detection and treatment of these diseases can prevent permanent damage to the retina. While OCT has been proven effective at diagnosing retinal pathology, most commercial systems are bulky and table mounted, limiting their screening capabilities. The compact and easy to use handheld device can be used to quickly screen patients outside of the ophthalmology clinic in primary care, pediatrics applications, or in the field in developing countries. A custom motion registration algorithm corrects for the additional operator motion in the images. The wide scanning angle combined with the high imaging speeds used in SS-OCT allows screening of pathology with a single volumetric data set spanning the areas of interest on the retina.