Photoelectric plethysmography. Ocular blood flow measurements in dogs.

Ocular blood flow in dogs was monitored loith 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 ocidar pulse amplitude correlated ivith concurrent blood gas analyses (arterial COi and O!). Hypercarbla and hypoxia increase the ocular pulse amplitude, while hypocarbia and hyperoxia decrease the ocular pulse amplitude. Variations in ocular pulse ampi.tude measured by photoelectric plethysmography may mirror changes in cerebral and ocular blood flow.