Three methods of measurement of the episcleral venous pressure were compared: a torsion balance method, a pressure chamber method, and a cannulation method. All three gave similar results, particularly the latter two, in a series of measurements in anesthetized rabbits. Cannulation gave the most reproducible results, had the sharpest endpoint, and was the most sensitive to pressure changes in a single vessel. The pressure chamber method was found to have a very reproducible endpoint and to give results which did not differ significantly from those obtained by direct cannulation. The torsion balance method was found to be less satisfactory because of difficulty in appreciating an endpoint and was found to give, significantly, the highest values of the three methods.
BRUBAKER RF. Determination of Episcleral Venous Pressure in the EyeA Comparison of Three Methods. Arch Ophthalmol. 1967;77(1):110-114. doi:10.1001/archopht.1967.00980020112024