Imaging of Ocular Blood FlowGh.Naderian , MD

The eye has two separate

and distinct circulatory

systems , the retinal and the

uveal.

The retinal vascular

system nourishes the inner

retina.

The uveal system supplies

the choroid , ciliary body and

iris.

Color Doppler imaging:Color Doppler imaging (CDI) is an

ultrasound technique combining B-

Scan gray scale imaging and blood

velocity measurements

CDI can be used to calculate peak

systolic velocities (PSVs) and end-

diastolic velocities (EDVs) in the

retrobulbar vessels , including the

OA,CRA and nasal and temporal

PCAs.

Canon laser Blood Flowmeter

The canon laser blood flowmeter

(CLBF) is a recently developed

device used to simultaneously

quantify the velocity of blood within

large retinal vessels and their

diameter.

Use of CLBF is limited by its

calculated flow assumptions ,

cataract , vitreous opacties ,

small pupills and eye movement.

Heidelberg Laser Doppler Flowmetry

The confocal scanning laser doppler

flowmeter , also known as the

Heidelberg retina fowmeler (HRF) ,

combines a laser doppler flowmeter

with a confocal scanning laser

tomograph.

Scanning Laser Ophthalmoscope Angiography

FA and ICG angiography

performed with a scanning lascr

opthalmoseope (SLO) can be

used to quantitate blood flow.

In SLO angiography fluorescein dye

may be used to evaluale the retinal

vasculature to yield homodynamic

measurements such as arteriovenous

passage (AVP) and meam dye velocity

(MDV)

Pulsatile Ocular Blood Flow Measurement

Pulsatile ocular blood flow

(POBF) devices consist of a

modifed Pneumotonometer

interfaced with a microcomputer

that records the ocular pulse.

POFB monitors the rhytmic

change in intraocular

pressure (IOP) during the

cardiac cycle,which fluctuates

up to 2mm Hg in sinusoidal

fashion

Clinical Applications1) Glaucomatous optic

Neuropathy

2) Diabetic Retinopathy

3) Age-related Macular

degeneration