Relationship between ciliary perfusion pressure and pattern-reversal visual evoked cortical potentials: an electro-encephalo-dynamographic investigation.

Pattern-reversal visual evoked cortical potentials (VECP) taken from 25 healthy volunteers before, during and after short-lasting elevation of intraocular pressure proved to be dependent on ciliary perfusion pressure (pp cil) in a characteristic way. Reductions of pp cil to ca. 30 mm Hg did not result in VECP changes. These results point to efficient autoregulation in the retinal circulation and in the circulatory region of the anterior part of the optic nerve. When pp cil was reduced to below 30 mm Hg a marked reduction of VECP amplitudes and prolongation of latencies were observed. An autoregulatory capacity of about 15 mm Hg was found.