PULSATILE FILLING OF DILATED CHOROIDAL VESSELS IN MACULAR WATERSHED ZONES.

These novel observations suggest the pressure gradient for flow in the affected veins varied from low gradients when the filling was slow to high gradients when the filling was faster. The vessels violated the physiological watershed zone and seem to function as anastomoses between the ordinarily segmented venous drainage of the choroid. The dilated segments may result in pooling of venous blood as part of venous outflow abnormalities that may be operative in these diseases.