|
Record 1
from database: MEDLINE
 Return
To Top Of Menu
- Title
- Ocular blood flow velocity in
age-related macular degeneration [see
comments]
- Author
- Friedman E; Krupsky S; Lane AM; Oak
SS; Friedman ES; Egan K; Gragoudas ES
- Address
- Massachusetts Eye and Ear Infirmary,
Boston 02114, USA.
- Source
- Ophthalmology, 1995 Apr, 102:4, 640-6
- Abstract
- BACKGROUND: Changes in the structure
of the ocular blood vessels associated
with age-related macular degeneration
(AMD) have been described in some
detail, but comparatively little is
known of the concomitant circulatory
changes. The goal of this study is to
evaluate changes in the ocular
circulation that may be associated with
AMD. METHODS: Ocular blood flow
velocities and vessel pulsatilities were
measured in volunteers with and without
AMD using a color Doppler imaging unit.
Spectral analyses were recorded from the
ophthalmic artery, central retinal
artery and vein, the temporal and nasal
short posterior ciliary arteries, and
the four vortex veins. RESULTS:
Adjusting for age, pulsatility indices
of all arteries were higher in subjects
with AMD (central retinal artery [P =
0.02]; temporal and nasal short
posterior ciliary arteries [P = 0.06 and
0.002, respectively]; and ophthalmic
artery [P = 0.24]). End-diastolic blood
flow velocity of the short posterior
ciliary arteries tended to decrease in
the presence of AMD. CONCLUSIONS: The
combination of increased pulsatility and
decreased velocity of the short
posterior ciliary arteries, observed in
the presence of AMD, are interpreted as
evidence of increased vascular
resistance. The clinical signs of AMD
may be related to degradation of the
metabolic transport function of the
retinal pigment epithelium, resulting
from impaired choroidal perfusion.
[Karl
Note: "Pulsatility" is
related to "Pulsatile" which
means: "characterized by a
rhythmical pulsation."
"higher pulsatility" presumably
means faster pulse, or a more rapid pulse --
or a faster rate of change in these blood
vessels of people with macular
degeneration.]
[Karl
Note: But, notice that blood flow was
decreased, indicating probably increased
resistance in the artery. Oral
chelation should improve the blood flow in
these arteries and reduce the problem of
macular degeneration.]
- Language of Publication
- English
- Unique Identifier
- 95241084
Return
To Top Of Menu
- MeSH Heading (Major)
- Eye|*BS; Macular Degeneration|*PP
- MeSH Heading
- Aged; Aged, 80 and over; Blood Flow
Velocity; Female; Human; Male; Middle
Age; Pulsatile Flow; Reproducibility of
Results; Support, Non-U.S. Gov't;
Ultrasonography, Doppler, Color;
Vascular Resistance
- Publication Type
- JOURNAL ARTICLE
- ISSN
- 0161-6420
- Country of Publication
- UNITED STATES
Record 2
from database: MEDLINE
Return
To Top Of Menu
- Title
- Progress in measurement of ocular
blood flow and relevance to our
understanding of glaucoma and
age-related macular degeneration.
- Author
- Harris A; Chung HS; Ciulla TA;
Kagemann L
- Address
- Department of Ophthalmology, Indiana
University, Indianapolis 46202, USA.
Alharris@indiana.edu
- Source
- Prog Retin Eye Res, 1999 Sep, 18:5,
669-87
- Abstract
- New technologies have facilitated the
study of the ocular circulation. These
modalities and analysis techniques
facilitate very precise and
comprehensive study of retinal,
choroidal, and retrobulbar circulations.
These techniques include: 1. Vessel
caliber assessment; 2. Scanning laser
ophthalmoscopic fluorescein angiography
and indocyanine green angiography to
image and evaluate the retinal
circulation and choroidal circulation
respectively; 3. Laser Doppler flowmetry
and confocal scanning laser Doppler
flowmetry to measure blood flow in the
optic nerve head and retinal capillary
beds;
-
- [Karl
Loren Note: Notice that the
"Doppler" diagnosis is also
called "ultrasound" about
which I have written a great deal,
at: http://www.karlloren.com/ultrasound/index.htm
]
-
- 4. Ocular pulse measurement; and 5.
color Doppler imaging to measure blood
flow velocities in the central retinal
artery, the ciliary arteries and the
ophthalmic artery. These technique have
greatly enhanced the ability to quantify
ocular perfusion defects in many
disorders, including glaucoma and
age-related macular degeneration, two of
the most prevalent causes of blindness
in the industrialized world. Recently it
has become clear, in animal models of
glaucoma, that retinal ganglion cells
die via apoptosis. The factors that
initiate apoptosis in these cells remain
obscure, but ischemia may play a central
role. Patients with either primary
open-angle glaucoma or normal-tension
glaucoma experience various ocular blood
flow deficits. With regard to
age-related macular degeneration, the
etiology remains unknown although some
theories include primary retinal pigment
epithelial senescence, genetic defects
such as those found in the ABCR gene
which is also defective in Stargardt's
disease and ocular perfusion
abnormalities. As the choriocapillaris
supplies the metabolic needs of the
retinal pigment epithelium and the outer
retina, perfusion defect in the
choriocapillaris could account for some
of the physiologic and pathologic
changes in AMD. Vascular defects have
been identified in both nonexudative and
exudative AMD patients using new
technologies. This paper is a
comprehensive update describing
modalities available for the measurement
of all new ocular blood flow in human
and the clinical use.
- Language of Publication
- English
- Unique Identifier
- 99364865
Return
To Top Of Menu
- MeSH Heading (Major)
- Diagnostic Techniques,
Ophthalmological|*; Eye|*BS; Glaucoma,
Open-Angle|*PP; Macular Degeneration|*PP
- MeSH Heading
- Animal; Blood Flow Velocity; Human;
Regional Blood Flow; Rheology
- Publication Type
- JOURNAL ARTICLE; REVIEW; REVIEW,
ACADEMIC
- ISSN
- 1350-9462
- Country of Publication
- ENGLAND
Record 3
from database: MEDLINE
Return
To Top Of Menu
- Title
- Color Doppler imaging of the
retrobulbar circulation in age-related
macular degeneration.
- Author
- Hosal BM; Karakoç G; Gürsel E; Camur
M
- Address
- Department of Ophthalmology, Ankara
Numune Hospital, Turkey.
- Source
- Eur J Ophthalmol, 1998 Oct, 8:4, 234-8
- Abstract
- PURPOSE: The aim of this study was to
assess hemodynamic changes in the
retrobulbar circulation in patients with
age-related macular degeneration (ARMD).
METHODS: Color Doppler imaging was used
to calculate blood flow velocities and
vascular resistance of the central
retinal artery, short posterior ciliary
artery and ophthalmic artery in patients
with ARMD and in control patients.
RESULTS: The average peak systolic
velocity was significantly lower in the
central retinal artery (p < 0.001),
posterior ciliary artery (p < 0.001)
and ophthalmic artery (p < 0.01) of
the patients with ARMD than in control.
End-diastolic blood flow velocities in
the retrobulbar arteries of ARMD
patients were also significantly lower
(p < 0.001) than controls. Gosling's
pulsatility index was significantly
higher in the ophthalmic artery (p <
0.01) and posterior ciliary artery (p
< 0.001) of eyes with ARMD. In
addition, the resistivity index was
significantly higher in all retrobulbar
arteries (p < 0.001) of these
patients. CONCLUSIONS: The hemodynamic
abnormalities in the retrobulbar
circulation suggest that vascular
impairment may play a role in the
pathogenesis of ARMD.
- Language of Publication
- English
- Unique Identifier
- 99109044
Order
full text for this document
- MeSH Heading (Major)
- Macular Degeneration|PA/*PP/US;
Orbit|*BS/US; Ultrasonography, Doppler,
Color|*
- MeSH Heading
- Aged; Aged, 80 and over; Blood Flow
Velocity; Ciliary Arteries|US;
Comparative Study; Female; Fluorescein
Angiography; Follow-Up Studies; Fundus
Oculi; Human; Male; Middle Age;
Ophthalmic Artery|US; Prospective
Studies; Pulsatile Flow; Retina|PA;
Retinal Artery|US; Vascular Resistance
- Publication Type
- JOURNAL ARTICLE
- ISSN
- 1120-6721
- Country of Publication
- ITALY
Record 4
from database: MEDLINE
Return
To Top Of Menu
- Title
- Foveolar choroidal blood flow in
age-related macular degeneration [see
comments]
- Author
- Grunwald JE; Hariprasad SM; DuPont J;
Maguire MG; Fine SL; Brucker AJ; Maguire
AM; Ho AC
- Address
- Department of Ophthalmology, Scheie
Eye Institute, School of Medicine,
University of Pennsylvania, Philadelphia
19104, USA.
- Source
- Invest Ophthalmol Vis Sci, 1998 Feb,
39:2, 385-90
- Abstract
- PURPOSE: To compare measurements of
the foveolar choroidal blood circulation
in subjects with nonexudative,
age-related macular degeneration (AMD)
with those of control subjects. METHODS:
Laser Doppler flowmetry was used to
assess relative choroidal blood velocity
(ChBVel), volume (ChBVol), and flow (ChBFlow)
in the center of the fovea. Measurements
were obtained in 20 eyes of 20 subjects
with 10 or more large drusen, visual
acuity of 20/32 or better, and no
evidence of choroidal neovascularization.
Findings obtained in these subjects were
compared with those of 10 eyes of 10
age- and blood pressure-matched control
subjects with no large drusen. Foveolar
choroidal blood flow measurements were
obtained by asking the study
participants to fixate on a probing
laser beam. RESULTS: No significant
differences in average age, blood
pressure, or intraocular pressure were
observed between subjects with AMD and
control subjects. In subjects with AMD,
average ChBVol was 0.24 +/- 0.08 (+/- 1
SD) arbitrary units (AU); this value was
33% lower than that of control subjects
(0.36 +/- 0.11 AU; two-tailed,
independent Student's t-test, P =
0.005). Average ChBVel, conversely, was
not significantly different from normal
(0.44 +/- 0.07 AU) in subjects with AMD
(0.44 +/- 0.10 AU). Average ChBFlow in
subjects with AMD (8.7 +/- 3.1 AU) was
37% lower than that of control subjects
(13.7 +/- 3.5 AU) (P = 0.0005). Average
blood flow pulsatility was 6% higher in
subjects with AMD (0.71 +/- 0.15) than
in control subjects (0.66 +/- 0.14), but
this difference was not statistically
significant (P = 0.42). CONCLUSIONS:
Average ChBFlow in the nonexudative
stages of AMD is lower than that of
age-matched controls, and the effect is
caused mainly by a decrease in ChBVol.
Further studies are needed to elucidate
whether decreased ChBFlow plays a role
in the development of choroidal
neovascularization, and whether ChBFlow
measurements may help identify subjects
with AMD at risk for developing
choroidal neovascularization.
- Language of Publication
- English
- Unique Identifier
- 98138485
Return
To Top Of Menu
- MeSH Heading (Major)
- Choroid|*BS; Fovea Centralis|*BS;
Macular Degeneration|*PP
- MeSH Heading
- Aged; Aged, 80 and over; Blood Flow
Velocity; Blood Pressure; Female; Human;
Intraocular Pressure; Laser-Doppler
Flowmetry; Male; Middle Age; Support,
Non-U.S. Gov't; Support, U.S. Gov't,
P.H.S.; Visual Acuity
- Publication Type
- JOURNAL ARTICLE
- ISSN
- 0146-0404
- Country of Publication
- UNITED STATES
Record 5
from database: MEDLINE
Return
To Top Of Menu
- Title
- Deep retinal vascular anomalous
complexes in advanced age-related
macular degeneration.
- Author
- Hartnett ME; Weiter JJ; Staurenghi G;
Elsner AE
- Address
- Harvard University, Boston, MA, USA.
- Source
- Ophthalmology, 1996 Dec, 103:12,
2042-53
- Abstract
- PURPOSE: The authors describe the
clinical characteristics of a group of
patients with age-related macular
degeneration (AMD), deep retinal
vascular anomalous complexes (RVACs),
advanced Bruch membrane changes, and
severe visual loss. Based on clinical
evaluation and imaging studies, the
authors hypothesize the cause of such
retinal vascular formations. PATIENTS
AND METHODS: The authors quantified an
initial case series of 6 patients and
expanded it to 11 patients (14 eyes)
with AMD and RVACs diagnosed by
fluorescein angiography or slit-lamp
examination. Associated pigment
epithelial detachments (PEDs) of 13 eyes
are described. In addition to the
clinical and fluorescein angiography
descriptions, infrared imaging and
indocyanine green angiography were used
to characterize more recently described
RVACs and fellow eyes. RESULTS: Each
study eye had a clearly defined
anastomosis connecting the retinal
circulation to a vascular complex in the
deep retina. The RVACs associated with
PEDs assumed a more central location
than did typical choroidal
neovascularization associated with PEDs.
In seven eyes with RVACs, there were
clinically recognizable retinovascular
findings: intraretinal hemorrhages,
telangiectasia, or microaneurysms. Legal
blindness occurred in 9 of 11 patients.
CONCLUSION: These results indicate that
retinovascular changes can be associated
with nondisciform AMD. The authors
speculate that neurodegenerative changes
and hypoxia may lead to such changes,
the RVAC being a more advanced finding.
Closure of an RVAC with photocoagulation
is difficult, perhaps because of its
higher blood flow. The visual outcome is
poor, not only because of the advanced
state of the underlying AMD, but also
because of the exudative nature of the
RVAC.
- Language of Publication
- English
- Unique Identifier
- 97156957
Return
To Top Of Menu
- MeSH Heading (Major)
- Arteriovenous Fistula|*ET/PA; Macular
Degeneration|*CO/PA; Retinal
Vessels|*AB/PA
- MeSH Heading
- Aged; Aged, 80 and over; Blindness|ET/PA;
Bruch Membrane|PA; Dyes|DU; Female;
Fluorescein Angiography; Fundus Oculi;
Human; Indocyanine Green|DU; Male;
Retinal Diseases|ET/PA; Retrospective
Studies; Support, Non-U.S. Gov't;
Support, U.S. Gov't, Non-P.H.S.;
Support, U.S. Gov't, P.H.S.; Vision
Disorders|ET/PA; Visual Acuity
- Publication Type
- JOURNAL ARTICLE
- ISSN
- 0161-6420
- Country of Publication
- UNITED STATES
Record 6
from database: MEDLINE
Return
To Top Of Menu
- Title
- A hemodynamic model of the
pathogenesis of age-related macular
degeneration [editorial]
- Author
- Friedman E
- Address
-
- Source
- Am J Ophthalmol, 1997 Nov, 124:5,
677-82
- Abstract
- The clinical message of this editorial
is that age-related macular degeneration
may be a vascular disorder. It may be a
manifestation of the hemodynamic
consequence of the process of lipoid
infiltration that, when it involves
other organs such as those of the
cardiovascular or cerebrovascular
systems, is called atherosclerosis. The
hemodynamic model presented here
postulates that in age-related macular
degeneration, the increase in resistance
to the flow of blood in the choroid is
caused by an age-related and
diet-related decrease in the compliance
of the sclera. It proposes that the form
of age-related macular degeneration
produced may depend on the relative
resistances of the ophthalmic and
cerebral circulations. A decrease in
perfusion, leading to the atrophic form
of age-related macular degeneration, is
the outcome if the resistance of the
cerebral circulation is relatively lower
than that of choroid. Conversely, a
relatively greater increase in the
increase in the hydrostatic pressure in
the choroidal vessels, leading to the
exudative form of the disorder.
- Language of Publication
- English
- Unique Identifier
- 98039991
Return
To Top Of Menu
- MeSH Heading (Major)
- Hemodynamics|*PH; Macular
Degeneration|*ET/PP; Models,
Biological|*
- MeSH Heading
- Blood Flow Velocity; Choroid|BS;
Human; Pigment Epithelium of Eye|ME;
Sclera|BS; Support, Non-U.S. Gov't;
Vascular Resistance|PH
- Publication Type
- EDITORIAL
- ISSN
- 0002-9394
- Country of Publication
- UNITED STATES
|
|
|
|
