Extending the Measurement Range in Ophthalmic Linear Optical Coherence Tomography using Dual Reference Path Interferometry

A fiber-based linear optical coherence tomography (LOCT) system employing a cost-effective CMOS camera has previously demonstrated high-resolution imaging suitable for retinal screening, including glaucoma monitoring. However, the system’s imaging depth was constrained to approximately 400 µm, insufficient for depth imaging of the optic nerve head (ONH), due to limitations imposed by the camera’s sensor size and pixel pitch. To overcome this limitation without replacing the economical and available sensor, we present a modification to the reference arm. By optimizing the utilization of the camera sensor’s vertical dimension, the system achieves an extended imaging depth, enabling the visualization of deeper tissue structures. Validation using an artificial eye model confirms that the modified LOCT system significantly enhances imaging depth while maintaining B-Scan quality. This advancement offers a cost-effective approach to extend the measurement range of LOCT systems, broadening their applicability in retinal imaging without altering the actual imaging sensor.