Abstract
Ocular blood flow in dogs was monitored with the use of a specially designed photoelectric plethysmograph transducer. The ocular pulse waves demonstrated were (1) of low amplitude, (2) coincident with cardiac systole, and (3) rapidly affected by stimuli known to influence cerebral blood flow. Changes in ocular pulse amplitude correlated with concurrent blood gas analyses (arterial pCO2 and pO2). Hypercarbia and hypoxia increase the ocular pulse amplitude, while hypocarbia and hyperoxia decrease the ocular pulse amplitude. Variations in ocular pulse amplitude measured by photoelectric plethysmography may mirror changes in cerebral and ocular blood flow.