Ophthalmodynamometry: a reliable method for measuring intracranial pressure.

Under physiological conditions, the pressure in the central retinal vein is equal to or higher than the intracranial pressure (ICP) because the cerebrospinal fluid (CSF) passes the sheath of the optic nerve before draining into the cavernous sinus. The optic nerve sheath is where the ICP affects the retinal venous pressure. Ophthalmodynamometry (ODM) is a useful method for determining the central retinal artery pressure. While papilledema and a lack of venous pulsations are commonly used as a vague indication of the ICP, ODM may be advantageous for determining the pressure in the central retinal vein. Until now, however, the venous pressure has never been compared with the intracranial pressure. In the present study, the pressure in the central retinal vein was recorded in 31 patients while the ICP was simultaneously being recorded for various reasons. The results demonstrate a linear correlation (r = 0.968) between the pressure in the central retinal vein and the ICP. This correlation is of great practic...