Depth-multiplexing spectral domain OCT for full eye length imaging with a single modulation unit

Abstract

Clinical measurement of a patient's axial eye length is emerging as a crucial approach to track progression and monitor management of myopia. However, the preferred method for such measurements is swept-source OCT, whose cost prohibits broad use, especially in lower-income communities. Spectral domain (SD) OCT is a more affordable option, but it has limited imaging depth range, so is not suitable for full eye length measurement. Depth-multiplexing (DM) techniques for SD-OCT provide a workaround by capturing images at multiple depths within the eye. However, these methods typically require multiple light modulation units or detectors for simultaneous imaging across depths, adding complexity and cost. In response, we propose a novel DM-SD-OCT approach that utilizes a single light modulation unit for depth encoding. We capture images at multiple depths within the eye simultaneously with a single line scan camera, then computationally demix the contributions from different depths. Here, we demonstrate acquisition and demixing of signals from three distinct depths within the eye and validate experimentally in human subjects. Our method thus offers a cost-effective solution for comprehensive eye length measurement in clinical myopia research.