Ocular circulation

•2 separate system of blood vessels to eye:

CRA - inner 2/3 (NFL --> OPL)

chorocapillaris - outer 1/3 (Photoreceptors --> ONL)

how do retinal blood vessels get to the eye

center of physiological cup

how do veins get to the eye

travel with arteries as they enter globe through ONH

arterioles vs venulues

arterioles:

•Narrower and lighter; brighter and straighter

no pulse

•There is a linear reflex along vessel center (middle 1/3) of the vessel)

venulues:

•Wider, darker and duller

•More curved or tortuous

•Have little if any reflex

•Assess the A/V ratio beyond the ___ Bifurcation

2nd

blood flow heart to brain

•Aortic arch:

-Brachiocephalic artery --> Right common carotid --> internal and external cc

-Left common carotid artery --> internal and external cc

-Left subclavian artery

CRA capillary networks

˃inner capillary plexus (ganglion cell layer)

˃outer capillary plexus (inner nuclear layer)

2 blood retinal barriers

1. outer = tight junction of RPE apical side

2. inner = nonleaky tight junctions of endothelial cells of CRA (retinal vessels)

what ocular tissue has the highest blood flow

choroid

perfusion pressure =

•P = P (arterioles) - P (venules)

-P(arterioles) = 65-70 mm Hg

-P(venules) = intraocular pressure

BV diameter is regulated by what in choroid and retina?

-Autonomic Nervous System

•CHOROID, CILIARY BODY, IRIS

•NOT IN RETINA

-Autoregulation

•RETINA, CILIARY BODY, IRIS

•NOT CHOROID