Assessment of retinal blood flow using Laser Speckle Flowgraphy

Abstract

SummaryLaser speckle flowgraphy (LSFG) is a promising technique for the two‐dimensional, non‐invasive assessment of ocular blood flow. We set out to investigate the use of this technique in healthy Caucasians. First, we evaluated the validity of retinal perfusion measurements by direct comparison with dual‐beam Doppler optical coherence tomography (D‐OCT). Relative flow volume (RFV), the main output parameter of LSFG, was in significant agreement with absolute blood flow measurements as obtained from D‐OCT in arteries (r = 0.69, P = 0.001) and veins (r = 0.74, P < 0.001). We also found that most of LSFG‐derived parameters were age‐dependent in a healthy population. In addition, retinal blood flow autoregulation during isometric exercise was studied using LSFG. Retinal blood flow started to increase significantly at ocular perfusion pressure levels that were 45% over baseline. These findings are comparable to data obtained in previous studies. The presented results show that LSFG can be applied to study ocular blood flow in healthy Caucasian subjects. The technique may also be used in patients with ocular diseases associated with vascular dysregulation such as glaucoma, age‐related macular degeneration or diabetic retinopathy in the future.