In vivo measurement of erythrocyte velocity and retinal blood flow using adaptive optics scanning laser ophthalmoscopy

In vivo adaptive optics microvascular imaging in diabetic patients without clinically severe diabetic retinopathy

“…The use of adaptive optics has allowed precise measurements of many cell types in the retina, including photoreceptors [1][2][3][4][5][6][7][8][9], retinal pigment epithelial (RPE) [10][11][12][13] cells, ganglion cell axon bundles [14,15], and erythrocytes [16][17][18][19]. Correcting the wavefront aberrations has also allowed imaging of capillaries at high resolution; increasing contrast and allowing detailed imaging of the perifoveal capillary network [18,[20][21][22][23][24].…”

“…However, by using near infrared light to improve retinal penetration [41], along with laser scanning and a confocal aperture to control unwanted scattered light [18,28], retinal microvascular structures can be imaged at high contrast and high resolution by correcting for each subject's individual optics. For retinal vessels that are perfused, the flow of erythrocytes and other cells can be imaged over time [16,17,23] to provide perfusion maps [21,23]. The perfusion maps allow us to directly evaluate whether capillaries have intact flow without requiring a contrast agent such as sodium fluorescein.…”

Imaging of retinal vasculature using adaptive optics SLO/OCT

“…This effect cannot be separated from shape distortions introduced by flow. In order to overcome this limitation many particles have to be investigated as can be done by switching into a different scanning mode that allows rapidly imaging of the same AO-SLO line over time and measuring the slope of the corresponding time resolved image [48,49] In a next step we recorded images with a larger field of view. Figure 4 shows an overview fundus image as well as en-face OCT and SLO images with a field of view of ~4°x4° and the focus and coherence plane kept constant.…”

Intravital Microscopy of the Spleen: Quantitative Analysis of Parasite Mobility and Blood Flow

“…Results from directionality and residence time of all the particles quantified are presented as a density distribution map of parasite population in Figure 2D and 2E, respectively. To monitor blood flow in the spleen using intravital microscopy, the streaks obtained in xt images of the central lumen of vessels resulting from the erythrocyte movement were measured to calculate velocity 11 Classify and label all the particles that appear in the first 10 time frames of the video according to the number of frames of residence (from 1 to 10). In each video, 20 particles will be tracked following the proportions obtained.…”