Clinical retinal imaging with Sensorless Adaptive Optics OCT and Angiography

Abstract

Purpose : Our research focuses expanding the applications of a clinical friendly AO-OCT. We will present our progress on our clinical Sensorless AO-OCT (SAO-OCT) system development, and demonstrate its functional retinal imaging performance through in vivo imaging of patients with various retinal pathologies.

Methods : Our recently developed SAO-OCT system is capable of depth-resolved high resolution retinal imaging by incorporating the Sensorless AO technique with a real-time 200kHz swept source OCT engine. For reliable aberration correction even in subjects with pathological retina, a high-stroke and high-speed deformable mirror (AlpAO DM97) was employed in the system. Using the polarization properties of the light, the system was designed to fit in a small footprint (12″ × 12″) without compromising imaging performance. By employing a novel scanning protocol and registration algorithm, high-resolution and high-contrast retinal vasculature imaging was also performed using SAO-OCT Angiography.

Results : Representative human photoreceptor cone mosaic images before and after aberration correction are shown in Fig.1 (a) – (b). Image quality improvement after the correction is clearly observed from the photoreceptor mosaic image (top) and the observation of Yellot’s ring in the power spectrum images (bottom). Figures 1 (c) – (e) show multi-scale SAO-OCT and Angiography images acquired close to the fovea. The photoreceptor mosaic and thin OPL capillaries are clearly visualized in Fig. 1 (d) – (e).
We have performed case reports on patients with various retinal pathologies, including Diabetic Retinopathy, Multiple Evanescent White Dot Syndrome, and Acute Macular Neuroretinopathy. As an example of our clinical studies, photoreceptor images acquired from Acute Zonal Occult Outer Retinopathy patient are shown in Fig. 2. From the photoreceptor images, an abnormal photoreceptor patch is observed at different scales. Quantification of the photoreceptors was performed using automated cone counting and Voronoi analysis.

Conclusions : We present a multi-scale OCT-A integrated SAO that is compact in size and well suited for a clinical setting. In combination with GPU-based real-time SAO-OCT Angiography, the operational complexity of the system was reduced while permitting interactive and dynamic high resolution functional retinal imaging. The SAO-OCT-A provides complementary images for clinical assessment of various retinal pathologies.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.