Fig. 1. The high-speed OCTA system. SLD, super luminescent diode; FC, fiber coupler; PC, polarization controller; L1, L2, collimating lenses; ND, neutral density filter; DC, dispersion controller; M, mirror; DS, displacement slide; FL, focus tunable lens; GM, two-dimensional scanning galvanometer; L3, achromatic doublet lens; L4, two achromatic doublet lens; AO card, analog digital card.

Fig. 2. (a) The light and dark changes of repeated scanning at two positions of a single capillary (repeat scanning 3 times for OCTA at each location). (b) High-speed OCTA image. The white dashed lines indicate the two scanning positions, and the yellow box illustrates the intermittent phenomenon produced by capillaries. The red solid lines and the green dashed lines represent two additional pairs of scanning positions that are equidistant from each other. (c) Different scanning protocols. The fast axis and slow axis waveforms are the signals that trigger the two galvanometers, respectively. (d) Capillary B-scan image processing at two locations. (e) Encoded images showing the variations in brightness over time of the same capillary cross-section at scanning positions S1 and S2.

Fig. 3. (a) High-speed OCTA image. (b)–(g) Local magnified images of the same position at different time points.

Fig. 4. Encoding of light and dark changes in the same capillary at different scanning intervals.

Fig. 5. Correlation of capillary light and dark coding. (a)–(e) Correlation of capillary light and dark coding with equal proportional increase in scanning spacing. (f) Correlation of light and dark coding of scanning positions across bifurcated capillaries.

Fig. 6. Changes in blood flow velocity in the same capillaries in the retina of mouse during anesthesia (n = 5, five measurements are taken at each location). Error bars = SEM.

Table 1. Summary of Different OCTA and Alternating Scan Imaging Protocols