The Uveal Venous Pressure

The uveal venous pressure is difficult to measure in most species and, consequently, it has been a matter of considerable speculation and disagreement. Some investigators⁷,⁸assumed that under normal conditions the pressure in the proximal part of the uveal veins UVP, is just high enough to prevent collapse of the vessels, while others⁹,¹⁰claimed that it is considerably higher. An increase in intraocular pressure, IOP, from the normal level, was considered by Kiss⁶to produce such a compression of the narrow intrascleral part of the vortex veins as to cause a serious uveal venous stasis. Seidel,⁸on the other hand, assumed that the UVP was raised just enough to balance the IOP. In a previous paper¹I demonstrated by indirect means that, in rabbits, the UVP is just above the IOP at normal and high IOP's and that the resistance in the veins draining the