The re-registration and differential processing of a series of images taken at 50-60 Hz produces a "flow movie", in which it is possible to follow the motion of individual clusters of red blood cells. The movie linked to here is derived from a series of eight aligned images, obtained over a period of 100 msec. Dividing each single image by the average of all produces eight corresponding differential images; played in order, these comprise the flow movie itself. Interpretation of a flow movie is straightforward: where there is a black spot, there is an erythrocyte or erythrocyte cluster. In white spots, or gaps, erythrocytes are absent.
Flow from a Patient with Branch Retinal Vein Occlusion (BRVO)
The direct nature of blood flow visualization allows simple inspection of a flow movie to quickly reveal gross abnormalities in flow, such as extremely slow or retrograde motion. The following link is to a movie obtained from a patient with BRVO. Refer to the red-free image montage and its legend for a further explanation of what the movie contains.
Impaired Flow in Proliferative Diabetic Retinopathy Patient
The following movies shows very slow flow in retinal blood vessels. The slow speed and relative scarcity of RBCs in the new vessels makes it possible to see flow even here, demonstrating the direct nature of the flow measurement being performed.
Using wide angle imaging, impaired flow is readily visible.
Choroidal flow visible after retinal degeneration due to AMD
This movie shows Choroidal flow in an eye with retinal degeneration due to AMD.
