Abstract
Purpose:
To investigate retinal arteriolar blood flow (RBF) and retinal oxygen tension (PO(2)) during decreases in systemic blood pressure (BP) in cats.
Methods:
The effect of acute decreased systemic blood pressure on RBF and PO(2) on near the arteriolar were assessed with laser Doppler velocimetry (CLBF model 100, Canon) and oxygen microelectrodes (POE-10N, BRC). The systemic BP was decreased over 5 minutes with continuous withdrawal of blood from the descending aorta at 24% of total blood volume using a syringe pomp (Model 11 Plus Advanced, Harvard Apparatus). Ocular perfusion pressure (OPP) was calculated as OPP = mean arterial BP (MABP) - IOP.
Results:
The RBF was maintained until 70mmHg of OPP and started to decrease (P<0.01) below 60 mmHg of OPP. The PO(2) was also maintained until 70mmHg of OPP and started to decrease (P<0.01) below 60 mmHg of OPP.
Conclusions:
These results suggest that RBF may be maintained more than 70 mmHg of OPP. The PO(2) seems to reflect RBF changes during acute decreasing systemic BP in cats.
Keywords: 568 intraocular pressure •
548 hypoxia •
688 retina