Wide-field retinal optical coherence tomography with wavefront sensorless adaptive optics for enhanced imaging of targeted regions

• Published in: Biomedical optics express Vol. 8; no. 1; pp. 16 - 37
• Main Authors: Polans, James, Keller, Brenton, Carrasco-Zevallos, Oscar M., LaRocca, Francesco, Cole, Elijah, Whitson, Heather E., Lad, Eleonora M., Farsiu, Sina, Izatt, Joseph A.
• Format: Journal Article
• Language: English
• Published: United States Optical Society of America 01.01.2017
• Subjects: (330.4460) Ophthalmic optics and devices; (330.7327) Visual optics, ophthalmic instrumentation; (170.4470) Ophthalmology; (170.4500) Optical coherence tomography; (330.4060) Vision modeling; (330.7326) Visual optics, modeling
• ISSN: 2156-7085; 2156-7085
• DOI: 10.1364/BOE.8.000016

The peripheral retina of the human eye offers a unique opportunity for assessment and monitoring of ocular diseases. We have developed a novel wide-field (>70°) optical coherence tomography system (WF-OCT) equipped with wavefront sensorless adaptive optics (WSAO) for enhancing the visualization of smaller (<25°) targeted regions in the peripheral retina. We iterated the WSAO algorithm at the speed of individual OCT B-scans (~20 ms) by using raw spectral interferograms to calculate the optimization metric. Our WSAO approach with a 3 mm beam diameter permitted primarily low- but also high- order peripheral wavefront correction in less than 10 seconds. In preliminary imaging studies in five normal human subjects, we quantified statistically significant changes with WSAO correction, corresponding to a 10.4% improvement in average pixel brightness (signal) and 7.0% improvement in high frequency content (resolution) when visualizing 1 mm (~3.5°) B-scans of the peripheral (>23°) retina. We demonstrated the ability of our WF-OCT system to acquire non wavefront-corrected wide-field images rapidly, which could then be used to locate regions of interest, zoom into targeted features, and visualize the same region at different time points. A pilot clinical study was conducted on seven healthy volunteers and two subjects with prodromal Alzheimer's disease which illustrated the capability to image Drusen-like pathologies as far as 32.5° from the fovea in un-averaged volume scans. This work suggests that the proposed combination of WF-OCT and WSAO may find applications in the diagnosis and treatment of ocular, and potentially neurodegenerative, diseases of the peripheral retina, including diabetes and Alzheimer's disease.