Unilateral ocular vascular stress in man and retinal responsivity in the contralateral eye

Autoregulation (AR), the capacity of retinal vessels to maintain a constant flow of blood during alterations in vascular perfusion pressure, has been studied by a variety of techniques. Psychophysical and electrophysiological procedures have been used as indirect measurements of the effectiveness of AR for maintaining normal visual function during altered ocular perfusion pressure (OPP) in a single eye. However, there have been no studies in normal subjects which have investigated the responsivity of the contralateral eye while the fellow eye undergoes transient vascular stress. In the present study, the components of the bilaterally recorded scotopic flash electroretinogram (ERG) were used as objective indices of visual neural function during transiently altered OPP. The principal finding was that a decrease in the OPP for the test eye was associated with a reversible attenuation of the retinal responsivity in that eye, and a supranormal oscillatory potential index in the contralateral eye. The existence of a central control mechanism, triggered at the eye level, may be responsible for this contralateral neural phenomenon.