High speed optical holography of retinal blood flow

TL;DR

This study introduces a high-speed, non-invasive holographic imaging technique to visualize retinal blood flow in rats with high spatial and temporal resolution using near-infrared laser light.

Contribution

The paper presents a novel holographic interferometry method for real-time, high-resolution imaging of retinal blood flow in vivo.

Findings

Successful imaging of retinal blood flow in large vessels

Achieved spatial resolution of 8 microns

Temporal resolution of 6.5 milliseconds

Abstract

We performed non-invasive video imaging of retinal blood flow in a pigmented rat by holographic interferometry of near-infrared laser light backscattered by retinal tissue, beating against an off-axis reference beam sampled at a frame rate of 39 kHz with a high throughput camera. Local Doppler contrasts emerged from the envelopes of short-time Fourier transforms and the phase of autocorrelation functions of holograms rendered by Fresnel transformation. This approach permitted imaging of blood flow in large retinal vessels (30 microns diameter) over 400 by 400 pixels with a spatial resolution of 8 microns and a temporal resolution of 6.5 ms.