Episcleral venous pressure and flow dynamics.

Episcleral venous pressure was measured by means of an air jet at different levels of occlusion of the measured vessel. This was repeated at different points in one branching venous plexus system. The results indicate that the most reliable estimate of the pressure is obtained at the pressure level at which the blood column becomes somewhat paler. Occlusion of the vessel causes a rise in venous pressure which may be considerable, especially in large veins.