[Autoregulation in the choroid]

The cerebral perfusion is continuously and highly sensitively dependent on arterial pCO2. Does the ocular perfusion behave in a similar manner? To answer this question, the authors measured the following parameters before and after the inhalation of 10% CO2: a) the increase of capillary pCO2, using a transcutaneous sensor, and b) the redness (pallor) of the retinal tissue, an expression of its hemoglobin content, was measured at two retinal locations with the Ocular Photometer (OPM). Initial results from young test-volunteers and patients with documented carotis stenoses show that the choroid is able to maintain constant its blood-volume even under changing loads.