Large Field-of-View Cellular Resolution Mapping of in vivo Retinas by Ultra-High Resolution Adaptive Optics - Optical Coherence Tomography (uhr-ao-oct)

Abstract

Purpose: : To test the feasibility of UHR-AO-OCT for creating large field-of-view cellular-resolution retinal volumes.

Methods: : An ultra-high resolution AO-FdOCT system (axial resolution, ~3.5 µm; lateral resolution, ~3.5 µm; acquisition speed: 18,000A-scans/s) constructed at UC Davis, was used for in vivo retinal imaging. The maximum lateral extent of a single UHR-AO-OCT volume acquired with this system is 1 mm (3 deg) due to the limited isoplanatic field with adaptive optics and instrument design. To overcome this limitation and to create retinal volumes that are similar in size to those of clinical FD-OCT systems, we acquired sets of UHR-AO-OCT sub-volumes at different retinal eccentricities with two different focus positions (one on inner retina and one on outer retina). Custom visualization software was used to stitch these sub-volumes in three dimensions into one large cellular resolution volume and then to co-register it with fundus photography.

Results: : As an example, a 5x5 mm lateral size cellular resolution volume was constructed from 50 (5x5x2) single UHR-AO-OCT volumes. This large volume uses ~2.5 million A-scans (5000x500) and offers exceptional detail within large volumetric structures of living retina.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • imaging/image analysis: clinical • retina