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The role of oxidative
stress in the pathogenesis of age-related macular
degeneration.
Beatty S, Koh H, Phil M, Henson D, Boulton M. Academic
Department of Ophthalmology, Manchester Royal Eye Hospital,
Manchester, United Kingdom.
Surv Ophthalmol 2000 Sep-Oct;45(2):115-34
Age-related macular degeneration (AMD) is the leading
cause of blind registration in the developed world, and yet
its pathogenesis remains poorly understood. Oxidative
stress, which refers to cellular damage caused by reactive
oxygen intermediates (ROI), has been implicated in many
disease processes, especially age-related disorders. ROIs
include free radicals, hydrogen peroxide, and singlet
oxygen, and they are often the byproducts of oxygen
metabolism. The retina is particularly susceptible to
oxidative stress because of its high consumption of oxygen,
its high proportion of polyunsaturated fatty acids, and its
exposure to visible light. In vitro studies have
consistently shown that photochemical retinal injury is
attributable to oxidative stress and that the antioxidant
vitamins A, C, and E protect against this type of injury.
Furthermore, there is strong evidence suggesting that
lipofuscin is derived, at least in part, from oxidatively
damaged photoreceptor outer segments and that it is itself
a photoreactive substance. However, the relationships
between dietary and serum levels of the antioxidant
vitamins and age-related macular disease are less clear,
although a protective effect of high plasma concentrations
of alpha-tocopherol has been convincingly demonstrated.
Macular pigment is also believed to limit retinal oxidative
damage by absorbing incoming blue light and/or quenching
ROIs. Many putative risk-factors for AMD have been linked
to a lack of macular pigment, including female gender, lens
density, tobacco use, light iris color, and reduced visual
sensitivity. Moreover, the Eye Disease Case-Control Study
found that high plasma levels of lutein and zeaxanthin were
associated with reduced risk of neovascular AMD. The
concept that AMD can be attributed to cumulative oxidative
stress is enticing, but remains unproven. With a view to
reducing oxidative damage, the effect of nutritional
antioxidant supplements on the onset and natural course of
age-related macular disease is currently being
evaluated.
Macular pigment and risk
for age-related macular degeneration in subjects from a
Northern European population.
Beatty S, Murray IJ, Henson DB, Carden D, Koh H, Boulton
ME. University Department of Ophthalmology, Manchester
Royal Eye Hospital, Manchester, UK.
stephen@stiofanbetagh.demon.co.uk
Invest Ophthalmol Vis Sci 2001 Feb;42(2):439-46
PURPOSE: Age and advanced disease in the fellow eye are
the two most important risk factors for age-related macular
degeneration (AMD). In this study, the authors investigated
the relationship between these variables and the optical
density of macular pigment (MP) in a group of subjects from
a northern European population.
METHODS: The optical density of MP was measured
psychophysically in 46 subjects ranging in age from 21 to
81 years with healthy maculae and in 9 healthy eyes known
to be at high-risk of AMD because of advanced disease in
the fellow eye. Each eye in the latter group was matched
with a control eye on the basis of variables believed to be
associated with the optical density of MP (iris color,
gender, smoking habits, age, and lens density).
RESULTS: There was an age-related decline in the optical
density of macular pigment among volunteers with no ocular
disease (right eye: r(2) = 0.29, P = 0.0006; left eye: r(2)
= 0.29, P < 0.0001). Healthy eyes predisposed to AMD
had significantly less MP than healthy eyes at no such risk
(Wilcoxon's signed rank test: P = 0.015).
CONCLUSIONS: The two most important risk factors for AMD
are associated with a relative absence of MP. These
findings are consistent with the hypothesis that
supplemental lutein and zeaxanthin may delay, avert, or
modify the course of this disease.
Lutein and zeaxanthin in
the eyes, serum and diet of human subjects.
Bone RA, Landrum JT, Dixon Z, Chen Y, Llerena CM.
Department of Physics, Florida International University,
Miami, FL 33199, USA.
Exp Eye Res 2000 Sep;71(3):239-45
Inverse associations have been reported between the
incidence of advanced, neovascular, age-related macular
degeneration (AMD) and the combined lutein (L) and
zeaxanthin (Z) intake in the diet, and L and Z
concentration in the blood serum. We suggest that persons
with high levels of L and Z in either the diet or serum
would probably have, in addition, relatively high densities
of these carotenoids in the macula, the so-called 'macular
pigment'. Several lines of evidence point to a potential
protective effect by the macular pigment against AMD. In
this study we examined the relationship between dietary
intake of L and Z using a food frequency questionnaire;
concentration of L and Z in the serum, determined by
high-performance liquid chromatography, and macular pigment
optical density, obtained by flicker photometry. Nineteen
subjects participated. We also analysed the serum and
retinas, as autopsy samples, from 23 tissue donors in order
to obtain the concentration of L and Z in these tissues.
The results reveal positive, though weak, associations
between dietary intake of L and Z and serum concentration
of L and Z, and between serum concentration of L and Z and
macular pigment density. We estimate that approximately
half of the variability in the subjects' serum
concentration of L and Z can be explained by their dietary
intake of L and Z, and about one third of the variability
in their macular pigment density can be attributed to their
serum concentration of L and Z. These results, together
with the reported associations between risk of AMD and
dietary and serum L and Z, support the hypothesis that low
concentrations of macular pigment may be associated with an
increased risk of AMD.
Macular pigment in donor
eyes with and without AMD: a case-control
study.
Bone RA, Landrum JT, Mayne ST, Gomez CM, Tibor SE,
Twaroska EE. Department of Physics, Florida International
University, Miami, Florida 33199, USA. bone@fiu.edu
Invest Ophthalmol Vis Sci 2001 Jan;42(1):235-40
PURPOSE: To determine whether there is an association
between the density of macular pigment in the human retina
and the risk of age-related macular degeneration (AMD).
METHODS: Retinas from 56 donors with AMD and 56 controls
were cut into three concentric regions centered on the
fovea. The inner, medial, and outer regions covered the
visual angles 0 degrees to 5 degrees, 5 degrees to 19
degrees, and 19 degrees to 38 degrees, respectively. The
amounts of lutein (L) and zeaxanthin (Z) extracted from
each tissue sample were determined by high-performance
liquid chromatography.
RESULTS: L and Z levels in all three concentric regions
were less, on average, for the AMD donors than for the
controls. The differences decreased in magnitude from the
inner to medial to outer regions. The lower levels found in
the inner and medial regions for AMD donors may be
attributable, in part, to the disease. Comparisons between
AMD donors and controls using the outer (peripheral) region
were considered more reliable. For this region, logistic
regression analysis indicated that those in the highest
quartile of L and Z level had an 82% lower risk for AMD
compared with those in the lowest quartile (age- and
sex-adjusted odds ratio = 0.18, 95% confidence interval =
0.05-0.64).
CONCLUSIONS: The results are consistent with a
theoretical model that proposes an inverse association
between risk of AMD and the amounts of L and Z in the
retina. The results are inconsistent with a model that
attributes a loss of L and Z in the retina to the
destructive effects of AMD.
Photodynamic therapy with
verteporfin (Visudyne): impact on ophthalmology and visual
sciences.
Bressler, N.M., Bressler, S.B.
Invest. Ophthalmol. Vis. Sci. 2000 Mar; 41(3): 624
8.
No abstract available.
Nutrition supplements and
the eye.
Brown NA, Bron AJ, Harding JJ, Dewar HM. Clinical
Cataract Research Unit, Nuffield Laboratory of
Ophthalmology, Oxford, UK.
Eye 1998;12 ( Pt 1):127-33
PURPOSE: A review of the role of vitamins, minerals,
carotenoids and essential fatty acids in relation to eye
health. The mode of action may be directly on the eye or by
promoting bodily health on which the eye depends.
RESULTS: The lens and retina suffer oxidative damage and
the anti-oxidant vitamins A, C and E are implicated as
protective. Studies in man give indifferent support to the
role of nutrition in the development of cataract. In the
elderly, vitamin intake may be inadequate, so that a
vitamin supplement may be reasonable. Zinc has a role in
retinal metabolism and may be beneficial in macular
degeneration. Selenium has an anti-oxidant role. Other
minerals including copper have a less defined role.
Carotenoids are concentrated at the macula and have an
anti-oxidant role. A reduced risk of macular degeneration
is found in relation to a high serum level. The essential
fatty acid, gamma-linolenic acid (GLA), is useful in
Sjogren's syndrome and may help in other dry eye
conditions. Omega-3 fatty acids are important in retinal
development and have a role in preventing cardiovascular
disease.
CONCLUSION: All persons should be encouraged to maintain
healthy nutrition. Middle-aged and elderly patients may
benefit from a supplement. An intake in excess of the
recommended daily intake may be beneficial, but this is not
proven. Further clinical trials are indicated to define the
advisability of vitamin, mineral and other supplements.
Dosages for recommended intake and for supplements are
given.
Ascorbic acid content of
human corneal epithelium.
Brubaker RF, Bourne WM, Bachman LA, McLaren JW.
Department of Ophthalmology, Mayo Clinic and Mayo
Foundation, Rochester, Minnesota 55905, USA.
brubaker.richard@mayo.edu
Invest Ophthalmol Vis Sci 2000 Jun;41(7):1681-3
PURPOSE: To measure the concentration of ascorbic acid
in the human corneal epithelium.
METHODS: Corneal epithelium was removed from postmortem
eyes 4 to 16 hours after death and ascorbate measured by
high-performance liquid chromatography.
RESULTS: The concentration of ascorbate was 1.33 +/-
0.48 mg/gm wet weight (mean +/- SD), estimated to be 14
times its concentration in the aqueous humor.
CONCLUSIONS: Ascorbate can protect the basal layer of
the epithelium by absorption of incident ultraviolet
radiation.
Glutathione: a vital lens
antioxidant.
Giblin FJ. Eye Research Institute, Oakland University,
Rochester, Michigan 48309-4401, USA. giblin@oakland.edu
J Ocul Pharmacol Ther 2000 Apr;16(2):121-35
The reducing compound glutathione (GSH) exists in an
unusually high concentration in the lens where it functions
as an essential antioxidant vital for maintenance of the
tissue's transparency. In conjunction with an active
glutathione redox cycle located in the lens epithelium and
superficial cortex, GSH detoxifies potentially damaging
oxidants such as H2O2 and dehydroascorbic acid. Recent
studies have indicated an important hydroxyl
radical-scavenging function for GSH in lens epithelial
cells, independent of the cells' ability to detoxify H2O2.
Depletion of GSH or inhibition of the redox cycle allows
low levels of oxidant to damage lens epithelial targets
such as Na/K-ATPase, certain cytoskeletal proteins and
proteins associated with normal membrane permeability. The
level of GSH in the nucleus of the lens is relatively low,
particularly in the aging lens, and exactly how the
compound travels from the epithelium to the central region
of the organ is not known. Recently, a cortical/nuclear
barrier to GSH migration in older human lenses was
demonstrated by Sweeney et al. The relatively low ratio of
GSH to protein -SH in the nucleus of the lens, combined
with low activity of the glutathione redox cycle in this
region, makes the nucleus especially vulnerable to
oxidative stress, as has been demonstrated with use of in
vivo experimental animal models such as hyperbaric oxygen,
UVA light and the glutathione peroxidase knockout mouse.
Effects observed in these models, which are currently being
utilized to investigate the mechanism of formation of human
senile nuclear cataract, include an increase in lens
nuclear disulfide, damage to nuclear membranes and an
increase in nuclear light scattering. A need exists for
development of therapeutic agents to slow age-related loss
of antioxidant activity in the nucleus of the human lens to
delay the onset of cataract.
[Antioxidants and
angiogenetic factor associated with age-related macular
degeneration (exudative type)]
Ishihara N; Yuzawa M; Tamakoshi A Department of
Ophthalmology, Nihon University School of Medicine, Tokyo,
Japan.
Nippon Ganka Gakkai Zasshi (Japan) Mar 1997, 101 (3)
p248-51
To confirm the hypothesis that antioxidants and
angiogenetic factors may be associated with the development
of age-related macular degeneration (exudative type), we
compared serum levels of vitamins A, C, and E and
carotinoid, zinc, selenium and b-FGF (basic-fibroblast
growth factor) in 35 patients with age-related macular
degeneration (exudative type) with the levels in 66
controls. The average serum zinc level was significantly
lower in the patient group than in the control group. Serum
vitamin E-alpha levels also tended to be lower. Most serum
b-FGF levels were below the standard value in each group.
Based on the above results, we conclude that subnormal
levels of zinc and vitamin E may be associated with the
development of age-related macular degeneration.
Thalidomide and
prednisolone inhibit growth factor-induced human retinal
pigment epithelium cell proliferation in
vitro.
Kaven C, Spraul CW, Zavazava N, Lang GK, Lang GE.
Department of Ophthalmology, University of Ulm,
Germany.
Ophthalmologica 2001 Jul-Aug;215(4):284-9
Thalidomide and prednisolone were recently introduced as
treatment modalities in age-related macular degeneration
(AMD). Growth factor-induced activation of retinal pigment
epithelial (RPE) cells is a crucial event in this disease.
The purpose was to examine the effect of thalidomide and
prednisolone on growth factor-preactivated RPE cells. Human
RPE cells were stimulated with 10 ng/ml platelet-derived
growth factor (PDGF), basic fibroblast growth factor
(bFGF), or vascular endothelial growth factor (VEGF) for 24
h. Afterwards, thalidomide (50 microg/ml) or prednisolone
(100 ng/ml) were added for 24 h. RPE cell proliferation was
determined by [3H]-thymidine incorporation. PDGF and bFGF
significantly stimulated human RPE cell proliferation (p
< 0.005), the value for VEGF stimulation was not
significant (p = 0.3). The effect of the growth factors was
diminished after addition of thalidomide and prednisolone
(p < 0.005). The current study shows that the
inhibitory properties of thalidomide and prednisolone
remain even after growth factor activation of the
cells.
Lutein, zeaxanthin, and
the macular pigment.
Landrum JT, Bone RA. Department of Chemistry, Florida
International University, Miami 33199, USA.
landrumj@fiu.edu
Arch Biochem Biophys 2001 Jan 1;385(1):28-40
The predominant carotenoids of the macular pigment are
lutein, zeaxanthin, and meso-zeaxanthin. The regular
distribution pattern of these carotenoids within the human
macula indicates that their deposition is actively
controlled in this tissue. The chemical, structural, and
optical characteristics of these carotenoids are described.
Evidence for the presence of minor carotenoids in the
retina is cited. Studies of the dietary intake and serum
levels of the xanthophylls are discussed. Increased macular
carotenoid levels result from supplementation of humans
with lutein and zeaxanthin. A functional role for the
macular pigment in protection against light-induced retinal
damage and age-related macular degeneration is discussed.
Prospects for future research in the study of macular
pigment require new initiatives that will probe more
accurately into the localization of these carotenoids in
the retina, identify possible transport proteins and
mechanisms, and prove the veracity of the photoprotection
hypothesis for the macular pigments.
Artificial tear
composition and promotion of recovery of the damaged
corneal epithelium.
Lopez Bernal D, Ubels JL. Department of Ophthalmology,
Medical College of Wisconsin, Milwaukee.
Cornea 1993 Mar;12(2):115-20
In severe dry eye syndromes the corneal epithelium is
compromised with development of punctate erosions and
increased permeability. In the present study the ability of
artificial tear solutions to promote recovery of the
corneal epithelial barrier was determined by measurement of
corneal uptake of 5,6 carboxyfluorescein (CF). Corneas of
anesthetized rabbits were exposed to 0.01% benzalkonium for
5 min to increase epithelial permeability. The cornea was
then exposed to an artificial tear solution for 1.5 h
followed by measurement of CF uptake. During exposure to
three commercial isotonic, nonpreserved solutions and a
solution preserved with polyquaternium-1, CF uptake
decreased significantly but did not return to control. No
recovery of the epithelial barrier occurred during exposure
of corneas to nonpreserved hypotonic solutions. During
exposure to an experimental tear solution with an
electrolyte composition similar to human tears, buffered
with bicarbonate, CF uptake returned to control levels.
Bicarbonate is an essential component of this solution
because the same formula buffered with borate or without
buffer was ineffective in promoting recovery of the damaged
corneal epithelium.
Changes in
choriocapillaris and retinal pigment epithelium in
age-related macular degeneration.
Lutty G, Grunwald J, Majji AB, Uyama M, Yoneya S. Wilmer
Eye Institute, Baltimore, MD 21287-9115, USA.
glutty@jhmi.edu
Mol Vis 1999 Nov 3;5:35
Retinal pigment epithelial cells (RPE) and the
choriocapillaris are on opposite sides of Bruch's membrane
and control transport in and out of the retina. In
age-related macular degeneration (AMD), they may also be
responsible for deposition of material in and on Bruch's
membrane and the formation or regression of choroidal
neovascularization (CNV). Indocyanine green (ICG)
angiography can be used to visualize the choroidal
vasculature and CNV. Filling of the choriocapillaris with
ICG was delayed in subjects older than 50 years of age, and
areas of hypofluorescence were observed in maculas of AMD
subjects, often associated with CNV. Laser Doppler
flowmetry of the choriocapillaris in the macula
demonstrated that choroidal blood flow and volume are
reduced in subjects older than 46 years of age and further
decreased in subjects with AMD. The human choriocapillaris
can be histologically studied in two dimensions by
incubating the tissue for alkaline phosphatase activity,
flat-embedding it in transparent polymer and sectioning it.
Using this technique, choriocapillaris dropout was found to
be associated with deposition of material in Bruch's
membrane in diabetic subjects. When RPE are removed from
Bruch's membrane, the choriocapillaris degenerates; the
regeneration of choriocapillaris can be blocked by
Genistein, a tyrosine kinase inhibitor. Finally, RPE cells
may produce substances that both stimulate the formation
and regression of CNV in animal models. These studies
suggest that there may be a reduction in choriocapillaris
flow in AMD, and this loss of choriocapillaris can be
associated with the Bruch's membrane deposits that are
hallmarks of AMD. Furthermore, RPE may stimulate the
formation and regression of CNV and RPE loss can result in
loss of choriocapillaris.
Effects of
ginkgo-biloba on the micro-vessels of bulbar
conjunctiva.
Piovella, C.
Minerva Med. 1973 Nov 7; 64(79, Suppl.): 4179-86 (in
Italian).
No abstract available
Lutein and zeaxanthin
concentrations in rod outer segment membranes from
perifoveal and peripheral human retina.
Rapp LM, Maple SS, Choi JH. Cullen Eye Institute,
Department of Ophthalmology, Baylor College of Medicine,
Houston, Texas 77030, USA. lrapp@bcm.tmc.edu
Invest Ophthalmol Vis Sci 2000 Apr;41(5):1200-9
PURPOSE: In addition to acting as an optical filter,
macular (carotenoid) pigment has been hypothesized to
function as an antioxidant in the human retina by
inhibiting the peroxidation of long-chain polyunsaturated
fatty acids. However, at its location of highest density in
the inner (prereceptoral) layers of the foveal retina, a
specific requirement for antioxidant protection would not
be predicted. The purpose of this study was to determine
whether lutein and zeaxanthin, the major carotenoids
comprising the macular pigment, are present in rod outer
segment (ROS) membranes where the concentration of
long-chain polyunsaturated fatty acids, and susceptibility
to oxidation, is highest.
METHODS: Retinas from human donor eyes were dissected to
obtain two regions: an annular ring of 1.5- to 4-mm
eccentricity representing the area centralis excluding the
fovea (perifoveal retina) and the remaining retina outside
this region (peripheral retina). ROS and residual
(ROS-depleted) retinal membranes were isolated from these
regions by differential centrifugation and their purity
checked by polyacrylamide gel electrophoresis and fatty
acid analysis. Lutein and zeaxanthin were analyzed by
high-performance liquid chromatography and their
concentrations expressed relative to membrane protein.
Preparation of membranes and analysis of carotenoids were
performed in parallel on bovine retinas for comparison to a
nonprimate species. Carotenoid concentrations were also
determined for retinal pigment epithelium harvested from
human eyes.
RESULTS: ROS membranes prepared from perifoveal and
peripheral regions of human retina were found to be of high
purity as indicated by the presence of a dense opsin band
on protein gels. Fatty acid analysis of human ROS membranes
showed a characteristic enrichment of docosahexaenoic acid
relative to residual membranes. Membranes prepared from
bovine retinas had protein profiles and fatty acid
composition similar to those from human retinas. Carotenoid
analysis showed that lutein and zeaxanthin were present in
ROS and residual human retinal membranes. The combined
concentration of lutein plus zeaxanthin was 70% higher in
human ROS than in residual membranes. Lutein plus
zeaxanthin in human ROS membranes was 2.7 times more
concentrated in the perifoveal than the peripheral retinal
region. Lutein and zeaxanthin were consistently detected in
human retinal pigment epithelium at relatively low
concentrations.
CONCLUSIONS: The presence of lutein and zeaxanthin in
human ROS membranes raises the possibility that they
function as antioxidants in this cell compartment. The
finding of a higher concentration of these carotenoids in
ROS of the perifoveal retina lends support to their
proposed protective role in age-related macular
degeneration.
Multicenter ophthalmic
and nutritional age-related macular degeneration
study--part 2: antioxidant intervention and
conclusions.
Richer S. Eye Clinic 112e, DVA Medical Center, North
Chicago, IL 60064, USA.
J Am Optom Assoc 1996 Jan;67(1):30-49
BACKGROUND: The experimental design, subjects,
procedures and baseline data for the prospective double
blind dry ARMD-antioxidant intervention study have been
described in Part 1.
METHODS: At eight DVA medical centers, 32 patients
(group one) were assigned a placebo and 39 patients (group
two) a "broad spectrum" antioxidant capsule. Data was
collected in five areas: demographic; ophthalmic; dietary
analysis of daily food intake; serum analysis; and adverse
gastrointestinal symptoms. Data was serially acquired at
baseline, 6 months, 12 months and 18 months, and was
analyzed by univariate repeated factors ANOVA, p =
0.05.
RESULTS: Group two (antioxidant po BID) maintained their
distance LogMAR visual acuity (p = 0.03), while there was a
trend toward both stabilized near M print (p = 0.07) and 6
cycle/degree contrast sensitivity (p approximately 0.10),
in left eyes. However, group two (antioxidant) also had
increased cortical opacification of the right lens (p =
0.04), compared to group one (placebo). Self perceived
stabilization of vision was reported by subjects in group
two and supported the objective data (Pearson chi square; p
= 0.05).
CONCLUSIONS: A specific 14 component antioxidant capsule
taken twice daily stabilized but did not improve dry ARMD
over the study period of 1.5 years. The ARMD stabilized
eyes had less advanced disease functionally but not by
fundus appearance. Decreased intake of cardioprotective
nutrients (vitamin E, zinc, magnesium, B6 and folate) in
ARMD patients remained constant over the course of the
trial.
[Radiotherapy and
age-related macular degeneration: a review of the
literature]
Schwartz LH; Schmitt T; Benchaboun M; Caputo G; Chauvaud
D; Balosso J; Faivre C; Francais C; Koenig F Service de
radiotherapie, hopital Saint-Louis, Paris, France.
Cancer Radiother (France) 1997, 1 (3) p208-12
Macular degeneration is a major health problem. Less
than 10% of the cases can be successfully treated by laser
therapy. Low dose radiation therapy (in the range of 20 Gy)
appears to decrease neovascularisation. These early results
need to be confirmed through a randomized trial. (38
Refs.)
Dietary fat and risk
for advanced age-related macular degeneration.
Seddon JM, Rosner B, Sperduto RD, Yannuzzi L, Haller JA,
Blair NP, Willett W. Epidemiology Unit, Department of
Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard
Medical School, Boston, MA 02114, USA.
Johanna_Seddon@meei.harvard.edu
Arch Ophthalmol 2001 Aug;119(8):1191-9
OBJECTIVE: To evaluate the relationship between intake
of total and specific types of fat and risk for advanced
age-related macular degeneration (AMD), the leading cause
of irreversible blindness in adults. DESIGN: A multicenter
eye disease case-control study.
SETTING: Five US clinical ophthalmology centers.
PATIENTS: Case subjects included 349 individuals (age
range, 55-80 years) with the advanced, neovascular stage of
AMD diagnosed within 1 year of their enrollment into the
study who resided near a participating clinical center.
Control subjects included 504 individuals without AMD but
with other ocular diseases. Controls were from the same
geographic areas as cases and were frequency-matched to
cases by age and sex.
MAIN OUTCOME MEASURES: Relative risk for AMD according
to level of fat intake, controlling for cigarette smoking
and other risk factors.
RESULTS: Higher vegetable fat consumption was associated
with an elevated risk for AMD. After adjusting for age,
sex, education, cigarette smoking, and other risk factors,
the odds ratio (OR) was 2.22 (95% confidence interval [CI],
1.32-3.74) for persons in the highest vs those in the
lowest quintiles of intake (P for trend,.007). The risk for
AMD was also significantly elevated for the highest vs
lowest quintiles of intake of monounsaturated (OR, 1.71)
and polyunsaturated (OR, 1.86) fats (Ps for trend,.03
and.03, respectively). Higher consumption of linoleic acid
was also associated with a higher risk for AMD (P for
trend,.02). Higher intake of omega-3 fatty acids was
associated with a lower risk for AMD among individuals
consuming diets low in linoleic acid, an omega-6 fatty acid
(P for trend,.05; P for continuous variable,.03).
Similarly, higher frequency of fish intake tended to reduce
risk for AMD when the diet was low in linoleic acid (P for
trend,.05). Conversely, neither omega-3 fatty acids nor
fish intake were related to risk for AMD among people with
high levels of linoleic acid intake.
CONCLUSION: Higher intake of specific types of
fat--including vegetable, monounsaturated, and
polyunsaturated fats and linoleic acid--rather than total
fat intake may be associated with a greater risk for
advanced AMD. Diets high in omega-3 fatty acids and fish
were inversely associated with risk for AMD when intake of
linoleic acid was low.
A prospective study of
cigarette smoking and age-related macular degeneration in
women.
Seddon JM, Willett WC, Speizer FE, Hankinson SE.
Epidemiology Unit, Massachusetts Eye and Ear Infirmary,
Boston, MA 02114, USA.
JAMA 1996 Oct 9;276(14):1141-6
OBJECTIVE: To evaluate the relationship between
cigarette smoking and incidence of age-related macular
degeneration (AMD) among women.
DESIGN: Prospective cohort study with 12 years of
follow-up (1980 to 1992), in which information on smoking
habits was updated every 2 years.
SETTING: Eleven states throughout the United States.
PARTICIPANTS: A total of 31 843 registered nurses
enrolled in the Nurses' Health Study who were aged 50 to 59
years in 1980 and did not report a diagnosis of cancer or
AMD at the beginning of the study. Additional women entered
the analytic cohort as they reached 50 years of age.
MAIN OUTCOME MEASURE: Incidence of AMD with visual
loss.
RESULTS: During 556 338 person-years of follow-up, 215
women were newly diagnosed as having AMD. After adjusting
for other risk factors for AMD, women who currently smoked
25 or more cigarettes per day had a relative risk (RR) of
AMD of 2.4 (95% confidence interval [CI], 1.4-4.0) compared
with women who never smoked. Past smokers of this amount
also had a 2-fold increased risk (RR=2.0; 95% CI, 1.2-3.4)
relative to never smokers. Compared with current smokers,
little reduction in risk was suggested even after quitting
smoking for 15 or more years. Risk of AMD also increased
with an increasing number of pack-years smoked (P for trend
<.001); among women who smoked for 65 or more
pack-years, the risk was 2.4 times the risk of never
smokers (95% CI, 1.5-3.8). Analyses of dry and exudative
types of AMD and other alternative definitions of AMD
revealed similar results.
CONCLUSIONS: Cigarette smoking is an independent and
avoidable risk factor for AMD among women. Because AMD is
the most common cause of severe visual impairment among the
elderly and treatment is not available or is ineffective
for most patients, reducing the risk of this disease is
another important reason to avoid smoking.
Dietary fat and fish
intake and age-related maculopathy.
Smith W, Mitchell P, Leeder SR. National Centre for
Epidemiology and Population Health, Australian National
University, Australian Capital Territory.
wayne.smith@anu.edu.au
Arch Ophthalmol 2000 Mar;118(3):401-4
OBJECTIVE: To assess whether dietary intake of fat or
fish is associated with age-related maculopathy (ARM)
prevalence.
DESIGN: Cross-sectional, urban population-based
study.
PARTICIPANTS: People (N = 3654) aged 49 years or
older.
MAIN OUTCOME MEASURES: Subjects with ARM were identified
from masked grading of retinal photographs. A
145-itemself-administered, semiquantitative food frequency
questionnaire was completed adequately by 88.8% of
participants and was used to assess intakes of dietary fat
and fish.
RESULTS: A higher frequency of fish consumption was
associated with decreased odds of late ARM (odds ratio for
frequency of consumption more than once per week compared
with less than once per month, 0.5). Subjects with higher
energy-adjusted intakes of cholesterol were significantly
more likely to have late ARM, with an increased risk for
late ARM for the highest compared with the lowest quintile
of intake (odds ratio, 2.7).
CONCLUSION: The amount and type of dietary fat intake
may be associated with ARM.
Continuing damage to
rat retinal DNA during darkness following light
exposure.
Specht S, Organisciak DT, Darrow RM, Leffak M.
Department of Biochemistry and Molecular Biology, Wright
State University School of Medicine, Dayton, OH 45435,
USA.
Photochem Photobiol 2000 May;71(5):559-66
The damaging effects of visible light on the mammalian
retina can be detected as functional, morphological or
biochemical changes in the photoreceptor cells. Although
previous studies have implicated short-lived reactive
oxygen species in these processes, the termination of light
exposure does not prevent continuing damage. To investigate
the degenerative processes persisting during darkness
following light treatment, rats were exposed to 24 h of
intense visible light and the accumulation of DNA damage to
restriction fragments containing opsin, insulin 1 or
interleukin-6 genes was measured as single-strand breaks
(ssb) on alkaline agarose gels. With longer dark treatments
all three DNA fragments showed increasing DNA damage.
Treatment of rats with the synthetic antioxidant
dimethylthiourea prior to light exposure reduced the
initial development of alkali-sensitive strand breaks and
allowed significant repair of all three DNA fragments. The
time course of double-strand DNA breaks was also examined
in specific genes and repetitive DNA. Nucleosomal DNA
laddering was evident immediately following the 24 h light
treatment and increased during the subsequent dark period.
The increase in the intensity of the DNA ladder pattern
suggests a continuation of enzymatically mediated apoptotic
processes triggered during light exposure. The protective
effects of antioxidant suggests that the light-induced DNA
degradative process includes both early oxidative reactions
and enzymatic processes that continue after cessation of
light exposure.
Suggested Reading
Abstracts
Antioxidant status and
neovascular age-related macular degeneration. Eye Disease
Case-Control Study Group.
Anon. [No authors listed]
Arch Ophthalmol. 1993 Jan;111(1):104-9.
We evaluated the hypothesis that higher serum levels of
micronutrients with antioxidant capabilities may be
associated with a decreased risk of neovascular age-related
macular degeneration by comparing serum levels of
carotenoids, vitamins C and E, and selenium in 421 patients
with neovascular age-related macular degeneration and 615
controls. Subjects were classified by blood level of the
micronutrient (low, medium, and high). Persons with
carotenoid levels in the medium and high groups, compared
with those in the low group, had markedly reduced risks of
neovascular age-related macular degeneration, with levels
of risk reduced to one half and one third, respectively.
Although no statistically significant protective effect was
found for vitamin C or E or selenium individually, an
antioxidant index that combined all four micronutrient
measurements showed statistically significant reductions of
risk with increasing levels of the index. Although these
results suggest that higher blood levels of micronutrients
with antioxidant potential, in particular, carotenoids, may
be associated with a decreased risk of the most visually
disabling form of age-related macular degeneration, it
would be premature to translate these findings into
nutritional recommendations.
Results of fluorescence
angiography of the posterior pole of the eye.
Baurmann, H.
Ber. Dtsch. Ophthal. Gesellsch. 1975; 73: 56-9. No
abstract available.
Subretinal
neovascularization in senile macular
degeneration.
Berkow JW.
Am J Ophthalmol. 1984 Feb;97(2):143-7.
When fluorescein angiograms from 563 patients with
senile macular degeneration examined at a large community
hospital during a 9.5-year period were retrospectively
reviewed, 200 patients were found to have a dry atrophic
type of senile macular degeneration, consisting of drusen
and retinal pigment epithelial changes. Of the 363 patients
with exudative senile macular degeneration, 244 had
subretinal neovascular membranes. Seventy-eight membranes
were less than 1 disk diameter in size. Most of the large
(157 of 224) and small (44 of 78) membranes showed a
predilection for the fovea. Only 13 large and six small
neovascular membranes were 200 microns or more from the
center of the foveal avascular zone.
Cigarette smoking and
age related macular degeneration.
Chan D Illinois College of Optometry, Chicago 60616,
USA.
Optom Vis Sci (United States) Jul 1998, 75 (7) p476
84
BACKGROUND: Age related macular degeneration (ARMD) is
one of the leading causes of severe visual impairment among
older Americans. Several hypotheses have been proposed
regarding the pathogenesis of ARMD. The possible
association of cigarette smoking and ARMD remains
controversial.
METHODS: Studies concerning the relationship between
cigarette smoking and ARMD are identified through the use
of Vision Articles Online and PubMed. Articles published
since 1970 are reviewed.
RESULTS: The literature reviewed strongly supports a
link between smoking and ARMD.
CONCLUSIONS: The identification of smoking as a risk
factor can lead to early intervention. Such intervention
may lessen visual loss from this disease, which has limited
medical treatment options. (92 Refs.)
Alternative therapies
in exudative age related macular degeneration
Chong N.H.V.; Bird A.C. N.H.V. Chong, Professorial Unit,
Institute of Ophthalmology (UCL), Moorfields Eye Hospital,
City Road, London EC1V 2PD United Kingdom Br. J.
Ophthalmol. 1998; 82(12): 1441-3.)
No abstract.
Age related macular
degeneration : a review of experimental
treatments.
Ciulla TA; Danis RP; Harris A Indiana University Macular
Degeneration Clinic and Research Center, Department of
Ophthalmology, Indiana University School of Medicine,
Indianapolis, USA.
Surv Ophthalmol (Netherlands) Sep Oct 1998, 43 (2) p134
46
Age related macular degeneration (AMD) is the leading
cause of irreversible visual loss in the USA. Laser
photocoagulation of choroidal neovascular membranes (CNVMs)
in exudative AMD is currently the only well studied and
widely accepted treatment modality. It is beneficial for
only a small minority of patients who show well demarcated
"classic" CNVMs, and it destroys normal retinal tissue,
creates a scotoma, and is associated with an unacceptably
high CNVM persistence and recurrence rate. Consequently,
investigators have attempted to develop new modalities for
treatment of CNVMs. These treatment modalities can be
grouped into four major categories: photodynamic therapy;
pharmacologic inhibition of CNVM formation with
antiangiogenic agents; surgical intervention, including
excision of subfoveal CNVMs; and radiation therapy. All of
these experimental treatment modalities are directed toward
destroyiing CNVMs, the end result of the exudative process,
and all have limitations. The ideal treatment of the future
must be based on the pathogenesis of the disease at a stage
well before CNVMs develop. Investigations in nonexudative
AMD are currently focusing on several major areas.
Epidemiologic factors, such as genetics, sunlight, and
nutrition, are being evaluated in several large studies,
including the Age Related Eye Disease Study, with the
possibility of ultimately limiting the risk of AMD through
behavior modification. Laser treatment of drusen is being
evaluated as a means of limiting the risk of CNVM
formation, although mixed results have been reported in the
small number of studies to date. Choroidal perfusion
abnormalities have been described in AMD, and some
investigators postulate that altering blood flow may limit
the risk of CNVM formation. No perfusion treatment trials
have been completed to date. (183 Refs.)
Low glutathione
reductase and peroxidase activity in age-related macular
degeneration.
Cohen SM, Olin KL, Feuer WJ, Hjelmeland L, Keen CL,
Morse LS. Department of Ophthalmology, University of
California, Davis, Sacramento 95816.
Br J Ophthalmol. 1994 Oct;78(10):791-4.
Age-related macular degeneration (ARMD) may result from
events initiated by reactive oxygen species. Blood samples
from 18 patients with ARMD and 18 similarly aged controls
were analysed for activities of important antioxidants.
Blood glutathione reductase activity was lower in patients
with ARMD compared with controls (p = 0.035). The
activities of glutathione peroxidase (p = 0.18) and
erythrocyte superoxide dismutase (p = 0.29) were similar
between the two groups by a Student's two sample t test.
Logistic regression was used to determine which enzyme
activities were associated with ARMD after adjusting for
possible confounding variables: smoking history, age,
multivitamin use, and cardiovascular disease. Glutathione
reductase activity (p = 0.05) and glutathione peroxidase
activity (p = 0.065) were significantly associated with
ARMD by this analysis. The relation of glutathione
reductase and glutathione peroxidase activity to ARMD
merits further study.
Sun exposure and age
related macular degeneration. An Australian case control
study.
Darzins P; Mitchell P; Heller RF McMaster University,
Division of Geriatric Medicine, Hamilton, Ontario,
Canada.
Ophthalmology (United States) May 1997, 104 (5) p770
6
BACKGROUND: The notion that sun exposure is a risk
factor for age related macular degeneration (AMD) is
widespread, but studies have not shown this
conclusively.
METHODS: To test the hypothesis that AMD cases have
greater ocular sun exposure than control subjects, the
authors compared 409 cases with 286 control subjects
resident in Newcastle, Australia. Sensitivity to sun and
glare of the participants was characterized. Sun exposure
was estimated from detailed histories and was validated
against sun seeking or avoidance behavior expected, given
sun sensitivity and history of treatment for skin
neoplasia.
RESULTS: Contrary to the authors' hypothesis, control
subjects had greater median annual ocular sun exposure (865
hours) than cases (723 hours), Mann Whitney U (U) = 45704,
z = 4.9, P > 0.0001. Cases had poorer tanning than
did control subjects (mean 2 = 18.2, 4 df, P = 0.001) and
as young adults were more sensitive to glare, odds ratio
(OR), 2.5; 95% confidence intervals (CIs), 1.8 to 3.5.
After stratifying by tanning ability, in the poor tanning
group, the median annual sun exposure of control subjects
(685 hours) exceeded that of cases (619 hours), U = 6556, z
= 1.9, P = 0.06. Among people who tanned well, control
subjects also had significantly greater annual sun exposure
than did cases (940 vs. 770 hours), U = 16263, z = 3.7, P =
0.0002.
CONCLUSIONS: Sensitivity to glare and poor tanning
ability are markers of increased AMD risk. Sun sensitivity
confounds study of the postulated AMD sunlight link.
Despite analyses stratified by sun sensitivity, sun
exposure was greater in control subjects than in cases with
AMD.
Antioxidant enzymes of
the human retina: effect of age on enzyme activity of
macula and periphery.
De La Paz MA, Zhang J, Fridovich I. Duke University Eye
Center, DUMC, Durham, NC 27710, USA.
Curr Eye Res. 1996 Mar;15(3):273-8.
The purpose of this research was to evaluate the effect
of age on protective antioxidant enzyme activity of normal
fresh cadaver human retina of the macula and periphery.
Antioxidant enzymes were assayed in tissue extracts
generated from 5 mm trephined punches of retina obtained
centered over the macula and the superior midperiphery of
normal fresh human cadaver retina. Cadaver tissue was
obtained from donors of a wide age range (age 7 to 85
years). The assays were performed within 6 h of enucleation
and within 24 h of donor death. Antioxidant enzymes assayed
included superoxide dismutase, catalase, glutathione
peroxidase, and glutathione reductase. Hexokinase and
glucose-6-phosphate dehydrogenase, enzymes not directly
involved in protection against oxidative damage, were
assayed for comparison. Enzyme specific activities were
calculated for the macula and periphery using protein
concentration of the extract as the denominator. Using
linear regression analysis, over the age range of 25 to 75
years, superoxide dismutase activity of the periphery but
not the macula tended to decline with age (p = 0.04, R2 =
0.21). Interindividual variability was high, and
variability increased with age. The difference between the
macular and peripheral enzyme activities for glutathione
peroxidase tended to decline with increasing donor age (p =
0.025, R2 = 0.33). There was no effect of age on the
specific activities of catalase, glucose-6-phosphate
dehydrogenase, and glutathione reductase. The specific
activity of hexokinase from the macula declined with
increasing donor age (p = 0.022, R2 = 0.43). Time from
death to enucleation or beginning of experiment was not a
significant factor. In summary, age does not have an effect
on the activity of major antioxidant enzymes of the macula
in normal human retina. There is a tendency for an effect
of age on peripheral superoxide dismutase activity and the
difference between macular and peripheral glutathione
peroxidase activity. High interindividual variability of
antioxidant enzyme activity exists in humans.
Inhibition of
glutathione reductase by flavonoids. A structure-activity
study.
Elliott AJ, Scheiber SA, Thomas C, Pardini RS. Allie M.
Lee Laboratory for Cancer Research, Department of
Biochemistry, University of Nevada, Reno 89557.
Biochem Pharmacol. 1992 Oct 20;44(8):1603-8.
A structure-activity study of fourteen chemically
related flavonoids was conducted to evaluate their
abilities to inhibit glutathione reductase (GR). By
comparing the I50 values of flavonoids from different
classes possessing an identical hydroxyl configuration, we
determined the following order of potency for inhibition of
GR: anthocyanidin > dihydroflavonol = chalcone
> flavonol > catechin. Enzyme inhibition by
delphinidin chloride and myricetin was partially prevented
in a N2 atmosphere which implicates a role for oxygen in
the mechanism of inhibition. To determine the role of
oxygen species in enzyme inhibition, GR was preincubated
with either mannitol, diethylenetriaminepenta-acetic acid
(DETAPAC), superoxide dismutase (SOD), catalase (CAT), or
SOD and CAT prior to assays for enzyme inhibition by
flavonoids. Enzyme inhibition by delphinidin chloride and
myricetin was suppressed by the addition of SOD, suggesting
that superoxide (O2-.) is involved. However, inhibition by
quercetin and morin was not sensitive to antioxidants. To
further investigate the role of O2-. in GR inhibition, a
superoxide generating system was utilized in the presence
and absence of flavonoid. The O2-. generating system failed
to inhibit GR in the absence of flavonoid but enhanced the
inhibition by myricetin, indicating that the O2-. did not
directly inhibit GR but reacted directly with certain
flavonoids to form a reactive intermediate which, in turn,
inhibited GR. These findings suggest that the mechanism of
inhibition of GR by flavonoids is complex and may have
oxygen-dependent and oxygen-independent components.
Oxidative protector'
enzymes in the macular retinal pigment epithelium of aging
eyes and eyes with age related macular
degeneration
Frank R.N. Dr. R.N. Frank, Kresge Eye Institute, Wayne
State Univ. Sch. of Medicine, Detroit, MI United States
Trans. of the Am. Ophthalmol. Soc. 1998, 96/ (635
689)
No abstract.
Flavonoids, a class of
natural products of high pharmacological
potency.
Havsteen B.
Biochem Pharmacol. 1983 Apr 1;32(7):1141-8
A review has been presented of the biochemistry and
pharmacology of a class of natural products, the
flavonoids. These substances which are widely distributed
in the plant kingdom and present in considerable quantities
in common food products, spices and beverages have in a
concentrated form (Propolis) been used since ancient times
by physicians and laymen to treat a great variety of human
diseases but they have yet to pass the tests of modern,
controlled, clinical experimentation. An attempt has been
made to present the fundamental evidence from the basic
biological sciences which is required to stimulate the
interest of the clinicians in this new field. The few
existing reports on the careful pharmacodynamic,
pharmacokinetic and clinical studies which have been made
have been summarized to provide a basis for a full-scale
investigation of the therapeutic potential of
flavonoids.
Antioxidants and
angiogenetic factor associated with age related macular
degeneration (exudative type)]
Ishihara N; Yuzawa M; Tamakoshi A Department of
Ophthalmology, Nihon University School of Medicine, Tokyo,
Japan.
Nippon Ganka Gakkai Zasshi (Japan) Mar 1997, 101 (3)
p248 51
To confirm the hypothesis that antioxidants and
angiogenetic factors may be associated with the development
of age related macular degeneration (exudative type), we
compared serum levels of vitamins A, C, and E and
carotinoid, zinc, selenium and b FGF (basic fibroblast
growth factor) in 35 patients with age related macular
degeneration (exudative type) with the levels in 66
controls. The average serum zinc level was significantly
lower in the patient group than in the control group. Serum
vitamin E alpha levels also tended to be lower. Most serum
b FGF levels were below the standard value in each group.
Based on the above results, we conclude that subnormal
levels of zinc and vitamin E may be associated with the
development of age related macular degeneration.
Oxidative effects of
laser photocoagulation.
Jennings PE, MacEwen CJ, Fallon TJ, Scott N, Haining WM,
Belch JJ. Department of Medicine and Ophthalmology,
Ninewells Hospital and Medical School, Dundee,
Scotland.
Free Radic Biol Med. 1991;11(3):327-30.
Diabetic proliferative retinopathy is a common and
sight-threatening condition. Oxidative stress is an
integral and possibly causative part of the pathogenesis.
Although laser photocoagulation is usually a beneficial
treatment it remains unclear how it works. The possibility
that it induces a sudden, temporary increase in free
radical activity either by direct thermal damage or by
oxygen reperfusion is explored in this clinical study by
measuring the oxidative status in the peripheral blood of
13 patients undergoing panretinal photocoagulation. There
were significant increases at one hour in
malondialdehyde-like material (MDA-LM), 8.1 (6.9-9.6)
nmol/mL, to 9.1 (7.6-9.8) nmol/mL, (less than 0.005);
plasma thiols (PSH), 423 (352-457) microns/L, to 444
(382-478) microns/L, (p less than 0.005) and red cell
reduced glutathione (GSH), 1357 (1295-1655) microns/L, to
1480 (1305-1760) microns/L, (p less than 0.01). Diene
conjugates rose over the first hour 0.55 (0.36-0.79) od/mL,
to 0.58 (0.34-0.85) od/mL falling to 0.56 (0.36-0.79) od/mL
at 2 h but these changes were not significant. At 2 h,
MDA-LM 8.4 (6.7-9.6) nmol/mL and PSH 404 (379-462)
microns/L had returned to baseline but GSH remained
significantly elevated 1500 (1325-1675) microns/L, (p less
than 0.005 compared to baseline). This is a new observation
and in some circumstances such generation of free radicals
could explain the mechanism behind the complications of
photocoagulation by direct or indirect damage to vascular
endothelium leading to increased vascular permeability
manifest as macular oedema or choroidal effusions.
Genetic association of
apolipoprotein E with age related macular
degeneration.
Klaver CC; Kliffen M; van Duijn CM; Hofman A; Cruts M;
Grobbee DE; van Broeckhoven C; de Jong PT Department of
Epidemiology, Erasmus University Medical School, Rotterdam,
The Netherlands.
Am J Hum Genet (United States) Jul 1998, 63 (1) p200
6
Age related macular degeneration (AMD) is the most
common geriatric eye disorder leading to blindness and is
characterized by degeneration of the neuroepithelium in the
macular area of the eye. Apolipoprotein E (apoE), the major
apolipoprotein of the CNS and an important regulator of
cholesterol and lipid transport, appears to be associated
with neurodegeneration. The apoE gene (APOE) polymorphism
is a strong risk factor for various neurodegenerative
diseases, and the apoE protein has been demonstrated in
disease associated lesions of these disorders.
Hypothesizing that variants of APOE act as a potential risk
factor for AMD, we performed a genetic association study
among 88 AMD cases and 901 controls derived from the
population based Rotterdam Study in the Netherlands. The
APOE polymorphism showed a significant association with the
risk for AMD; the APOE epsilon4 allele was associated with
a decreased risk (odds ratio 0.43 [95% confidence interval
0.21 0. 88]), and the epsilon2 allele was associated with a
slightly increased risk of AMD (odds ratio 1.5 [95%
confidence interval 0.8 2. 82]). To investigate whether
apoE is directly involved in the pathogenesis of AMD, we
studied apoE immunoreactivity in 15 AMD and 10 control
maculae and found that apoE staining was consistently
present in the disease associated deposits in AMD maculae
that is, drusen and basal laminar deposit. Our results
suggest that APOE is a susceptibility gene for AMD.
[Treatment of senile
macular degeneration with Ginkgo biloba extract. A
preliminary double-blind drug vs. placebo study]
[Article in French]
Lebuisson DA, Leroy L, Rigal G.
Presse Med. 1986 Sep 25;15(31):1556-8.
Senile macular degeneration is a frequent cause of
blindness for which there is no satisfactory medical
treatment. A double-blind trial comparing Ginkgo biloba
extract with a placebo was conducted in 10 out-patients at
the Hopital Foch. Drug effectiveness was assessed on the
results of fundoscopy and of measurements of visual acuity
and visual field. In spite of the small population sample,
a statistically significant improvement in long distance
visual acuity was observed after treatment with Ginkgo
biloba extract. The assumed pathogenesis of senile macular
degeneration is discussed with emphasis on free oxygenated
radicals.
Studies on Vaccinium
myrtillus anthocyanosides. I. Vasoprotective and
antiinflammatory activity.
Lietti A, Cristoni A, Picci M.
Arzneimittelforschung. 1976;26(5):829-32.
A Vaccinium myrtillus anthocyanosides preparation
(equivalent to 25% of anthocyanidins) demonstrated
significant vasoprotective and antioedema properties in
exerimental animals. In rabbits, the skin capillary
permeability increase, due to chloroform, was reduced both
after i.p. (25--100 mg/kg) and oral administration
(200--400 mg/kg) of anthocyanosides. Their activity was
more lasting in comparison to rutin or mepyramine and this
did not seem to be due to a specific antagonism towards
inflammatory process mediators such as histamine or
bradykinin. Experiments carried out in rats demonstrated
that Vacinium myrtillus anthocyanosides were effective both
in skin capillary permeability test as well as on vascular
resistance of rats fed a P factor deficient diet. In the
former test effective doses were in the range of 25--100
mg/kg (by oral route). In both the animal species
investigated, anthocyanosides were two-fold more active
when compared to the flavonoid rutin. Vaccinium myrtillus
anthocyanosides by oral route inhibited carrageein paw
oedema in rats showing a dose-response relationship. An
antioedema activity was detected also after i.v. or topical
application.
Photodynamic therapy
with verteporfin for choroidal neovascularization caused by
age-related macular degeneration: Results of a single
treatment in a phase 1 and 2 study
Miller J.W.; Schmidt-Erfurth U.; Sickenberg M.;
Pournaras C.J.; Laqua H.; Barbazetto I.; Zografos L.;
Piguet B.; Donati G.; Lane A.-M.; Birngruber R.; Van den
Berg H.; Strong H.A.; Manjuris U.; Gray T.; Fsadni M.;
Bressler N.M.; Gragoudas E.S. Dr. J.W. Miller, Laser
Research Laboratory, Retina Service, Massachusetts Eye and
Ear Infirmary, 243 Charles St, Boston, MA 02114 United
States AUTHOR EMAIL: jwmiller@meei.harvard.edu
Archives of Ophthalmology 1999, 117/9 (1161-1173)
Objective: To evaluate the safety and short-term visual
and fluorescein angiographic effects of a single
photodynamic therapy treatment with verteporfin with the
use of different dosage regimens in patients with choroidal
neovascularization (CNV) from age-related macular
degeneration. Design: Nonrandomized, multicenter,
open-label, clinical trial using 5 dosage regimens.
Setting: Four ophthalmic centers in North America and
Europe providing retinal care. Participants: Patients with
subfoveal CNV caused by age-related macular degeneration.
Methods: Standardized protocol refraction, visual acuity
testing, ophthalmic examination, color photographs, and
fluorescein angiograms were used to evaluate the effects of
a single treatment of photodynamic therapy with
verteporfin. Follow-up was planned through 3 months in 97
patients and for less than 3 months in 31 other patients.
Results: The mean visual acuity change (and range of
change) from baseline at the follow-up examination at week
12 after a single treatment with regimens 1 through 5 was
-0.2 (-3 to +2), -0.9 (-9 to +5), -1.6 (-9 to +2), +0.4 (-8
to +7), and +0.1 (-8 to +9) lines, respectively. Only the
highest light dose (150 J/cmsup 2) in regimens 2 and 3,
which produced angiographic nonperfusion of neurosensory
retinal vessels, caused marked vision loss. Some cessation
of fluorescein leakage from CNV was achieved without loss
of vision when the light dose used was less than 150
J/cmsup 2. Systemic adverse events were rare. Cessation of
fluorescein leakage from CNV was noted in all regimens by 1
week after photodynamic therapy. Fluorescein leakage from
at least a portion of the CNV reappeared by 4 to 12 weeks
after treatment in almost all cases. Progression of classic
CNV beyond the area of CNV identified before treatment was
noted in 42 (51%) of the 83 eyes with classic CNV followed
up for 3 months after a single treatment. Eyes in which the
area of any CNV leakage at 12 weeks was less than at
baseline had a significantly better visual acuity outcome
(+0.8 line) than eyes in which CNV leakage progressed (-0.8
line). Conclusions: Photodynamic therapy with verteporfin
achieved short-term cessation of fluorescein leakage from
CNV without loss of vision or growth of classic CNV in some
patients with age- related macular degeneration. Except for
nonperfusion of neurosensory retinal vessels at a light
dose of 150 J/cmsup 2, no other adverse events were of
concern. Randomized clinical trials to investigate whether
this new modality can preserve vision in patients with CNV
secondary to age-related macular degeneration are
justified.
Nutrition in the
elderly.
Morley JE, Mooradian AD, Silver AJ, Heber D,
Alfin-Slater RB. Department of Medicine, University of
California School of Medicine, Los Angeles.
Ann Intern Med. 1988 Dec 1;109(11):890-904.
Nutritional modulation is one approach to successful
aging. In animals, dietary restriction increases life span.
Alterations in the macronutrient and micronutrient
constituent of the diet can modulate gene expression.
Anorexia is common in elderly persons. The results of
studies in animals suggest that aging is associated with a
decrease in the opioid feeding drive and an increase in the
satiating effect of cholecystokinin. Unrecognized
depression is a common, treatable cause of anorexia and
weight loss in elderly persons. Protein synthesis decreases
in elderly persons; nevertheless, nitrogen balance can be
maintained in patients with fairly low intakes of protein.
Carbohydrate intolerance is common and may be modulated by
nutritional intervention and physical activity. The role of
cholesterol in the development of heart disease in very old
persons is controversial. Homebound and institutionalized
elderly persons often do not expose their skin to sunlight;
because the skin of older persons has a decreased ability
to form vitamin D, the vitamin D status in these persons is
precarious and they are at risk for osteopenia. Vitamins
are often abused by elderly persons. Drug administration
alters the vitamin requirements of persons. Borderline zinc
state has been associated with deteriorating immune
function, especially in persons who have diabetes mellitus
or who abuse alcohol. Zinc administration appears to
protect against the deteriorating vision associated with
age-related macular degeneration. Selenium deficiency seems
to be associated with an increased prevalence of
cancer.
Studies on the
mechanism of early onset macular degeneration in cynomolgus
monkeys. II. Suppression of metallothionein synthesis in
the retina in oxidative stress.
Nicolas MG, Fujiki K, Murayama K, Suzuki MT, Shindo N,
Hotta Y, Iwata F, Fujimura T, Yoshikawa Y, Cho F, Kanai A.
Department of Ophthalmology, Juntendo University School of
Medicine, Tokyo, Japan.
Exp Eye Res. 1996 Apr;62(4):399-408.
Initial investigations done in this laboratory detected
increased albumin and decreased glyceraldehyde 3-phosphate
dehydrogenase concentrations in the retina of an animal
model manifesting early onset macular degeneration. Both
glyceraldehyde 3-phosphate dehydrogenase and albumin are
markers of oxidative stress in cells. In this study, we
used the same animal model to study further biochemical and
physiological processes which may be involved in the
pathogenesis of early onset macular degeneration in
monkeys. We detected 60% lower catalase and glutathione
peroxidase activities in the affected retinas suggesting
lower antioxidant activities and oxidative stress. One of
the consequences of oxidative stress is the production of
metallothionein, a low molecular weight protein also
induced by high concentrations of heavy metals such as
zinc. Metallothionein was detected by RT-PCR in these
monkey retinas. However initial quantitative PCR studies on
this protein showed that the synthesis of metallothionein
in affected retinas appears to be less than in normal
controls. The affected retinas also showed a fourfold lower
zinc concentration compared with the normal controls. No
significant difference however, could be detected in the
zinc concentrations in plasma samples. Since induction of
metallothionein synthesis is mediated by transcription
factors which require heavy metals such as zinc for binding
to specific sites in the DNA, the lowered zinc
concentration may, thus, correlate with the lowered
metallothionein expression. And since metallothionein is
suggested to function as a free radical scavenger, the
lowered metallothionein synthesis may consequently
contribute to increased peroxidation reactions in the
affected retinas. It appears therefore, that oxidative
stress and the decreased metallothionein synthesis may be
involved in the pathogenesis of early onset macular
degeneration in this animal model.
[Th clinical picture of
retinal thrombosis (author's transl)] [Article in
German]
Niesel P.
Klin Monatsbl Augenheilkd. 1977 Feb;170(2):186-92.
Besides the acute arterial occlusion and simple venous
thrombosis, the clinical symptomatology may include signs
of chronic arterial insufficiency, i.e. progressive
blurring of vision, absolute visual field defects, cotton
wool exudates, capillary occlusion and increased retinal
circulation time. The poor visual prognosis is caused by
progressive macular degeneration. In the case of acute
arterial thrombosis, fragmentation of the blood column and
absence of arterial pulsation are indicative of pronounced
retinal ischemia. The ophthalmoscopic aspect of a visible
embolus may be a hint for the prognosis of eventual
recanalisation.
Moderate wine
consumption is associated with decreased odds of developing
age related macular degeneration in NHANES 1 [see
comments]
Obisesan TO; Hirsch R; Kosoko O; Carlson L; Parrott M
Department of Internal Medicine, Howard University
Hospital, Washington, DC 20060, USA.
J Am Geriatr Soc (United States) Jan 1998, 46 (1) p1
7
OBJECTIVE: To determine the association between alcohol
intake and the risk of developing age related macular
degeneration (AMD).
DESIGN: Case control study. PARTICIPANTS: The sample
consisted of 3072 adults 45 to 74 years of age with macular
changes indicative of AMD who participated in a nationally
representative sample of the first National Health
Nutrition and Examination Survey (NHANES 1) between 1971
and 1975: (a) the ophthalmology data set and (b) the
medical history questionnaire.
MAIN OUTCOME MEASURES: Alcohol intake and the risk of
developing AMD were measured. AMD was determined by staff
at the National Eye Institute by fundoscopy examination
using standardized protocol.
RESULTS: Overall, 184 individuals (6%) had AMD. We
observed a statistically significant but negative
association between AMD and the type of alcohol consumed in
a bivariate model (OR 0.86; 95% CI 0.73, 0.99). In the same
model, age maintained a consistently strong association
with AMD (OR 1.08; 95% CI 1.06 1.11; P < .001).
Among the different types of alcohol consumed in NHANES 1
(beer, wine, and liquor), the effect of wine, either alone
(OR 0.66; 95% CI 0.55 0.79) or in combination with beer (OR
0.66; 95% CI 0.55 0.79) or liquor (OR 0.74; 95% CI 0.63
0.86), dominated the negative association observed between
AMD and alcohol type. Additionally, a statistically
significant and negative association between wine and AMD
was noted after adjusting for the effect of age, gender,
income, history of congestive heart failure, and
hypertension (OR 0.81; 95% CI 0.67 0.99).
CONCLUSION: Moderate wine consumption is associated with
decreased odds of developing AMD. Health promotion and
disease prevention activities directed at cardiovascular
disease may help reduce the rate of AMD associated
blindness among older people. The nature and
pathophysiology of this association warrant further
investigation.
Zinc as a treatment for
age related macular degeneration
Olson R.J.; DeBry P. Dr. R.J. Olson, Department of
Ophthalmology, University Utah Health Sciences Ctr., John
A. Moran Eye Center, 50 North Medical Drive, Salt Lake
City, UT 84124 United States
Journal of Trace Elements in Experimental Medicine 1998,
11/2 3 (137 145)
Evidence continues to increase that antioxidants are an
important factor in the progress and development of age
related macular degeneration. While zinc supplementation
fits nicely in this thesis as a mineral co factor of vital
antioxidant enzymes, the clinical evidence for oral zinc
supplementation is mixed and presently inconclusive.
The evoked cortical
potential in macular degeneration.
Orpin, J.A., Orpin, E., McCulloch, C.
J. Am. Geriatr. Soc. 1974 Dec; 22(12): 536-7.
Results with
anthocyanosides from Vaccinium myrtillus equivalent to 25%
of anthocyanidines in the treatment of haemorrhagic
diathesis due to defective primary
haemostasis.
Piovella, F., Almasio, P., Ricetti, M.M. et al.
Gazz. Med. Ital. 1981; 140(10): 445-9.
No abstract available.
Antioxidant enzymes in
RBCs as a biological index of age related macular
degeneration.
Prashar S, Pandav SS, Gupta A, Nath R. Department of
Biochemistry, Postgraduate Institute of Medical Education
and Research, Chandigarh, India.
Acta Ophthalmol (Copenh). 1993 Apr;71(2):214-8.
The present study was undertaken to assess the levels of
antioxidant enzymes in red blood cells of subjects with
age-related macular degeneration and age-matched controls.
The results obtained show a significant decrease in
activities of superoxide dismutase (p < 0.001) and
glutathione peroxidase (p <0.001) as compared to the
controls. A good correlation (r = -0.99) was alsoobserved
between age and decreased activity of antioxidant enzymes
in controls, and also correlated well with age-related
macular degeneration. In conclusion, oxidative stress as
assessed by antioxidant enzymes is more pronounced in
subjects with age-related macular degeneration as compared
to age-matched controls.
Atrophic macular
degeneration. Rate of spread of geographic atrophy and
visual loss.
Schatz H, McDonald HR. Retina Research Fund, St. Mary's
Hospital and Medical Center, San Francisco, California.
Ophthalmology. 1989 Oct;96(10):1541-51.
The authors studied 50 eyes with atrophic (dry) macular
degeneration (geographic atrophy of age-related macular
degeneration [GAMD], in 50 consecutive patients for 2 to 6
years (average, 3.4 years). There were 35 women and 15 men
ranging in age from 60 to 89 years (average, 73 years). The
areas of atrophy tended to follow the disappearance or
flattening of soft drusen, pigment epithelial detachment,
or reticular mottling of the retinal pigment epithelium.
The atrophic areas were multifocal in 20 of the 50 eyes.
Atrophy of the retinal pigment epithelium was followed by
atrophy of the choriocapillaris. The atrophic areas tended
to expand (average rate in one direction, 139 microns per
year) and cause gradual loss of central visual acuity. The
rate of significant visual loss (from 20/50 or better to
20/100 or worse) was 8% of eyes per year. There was a
tendency toward resistance of the spread of atrophy into
the fovea. The atrophy tended to expand faster in patients
under age 75 and slower in patients aged 75 and over.
Subretinal neovascularization developed in ten of the 50
eyes
Radiotherapy and age
related macular degeneration: a review of the
literature]
Schwartz LH; Schmitt T; Benchaboun M; Caputo G; Chauvaud
D; Balosso J; Faivre C; Francais C; Koenig F Service de
radiotherapie, hopital Saint Louis, Paris, France.
Cancer Radiother (France) 1997, 1 (3) p208 12
Macular degeneration is a major health problem. Less
than 10% of the cases can be successfully treated by laser
therapy. Low dose radiation therapy (in the range of 20 Gy)
appears to decrease neovascularisation. These early results
need to be confirmed through a randomized trial. (38
Refs.)
Dietary carotenoids,
vitamins A, C, and E, and advanced age-related macular
degeneration. Eye Disease Case-Control Study
Group.
Seddon JM, Ajani UA, Sperduto RD, Hiller R, Blair N,
Burton TC, Farber MD, Gragoudas ES, Haller J, Miller DT, et
al. Epidemiology Unit, Massachusetts Eye and Ear Infirmary,
Boston 02114.
JAMA. 1994 Nov 9;272(18):1413-20.
OBJECTIVE--To evaluate the relationships between dietary
intake of carotenoids and vitamins A, C, and E and the risk
of neovascular age-related macular degeneration (AMD), the
leading cause of irreversible blindness among adults.
DESIGN--The multicenter Eye Disease Case-Control Study.
SETTING--Five ophthalmology centers in the United States.
PATIENTS--A total of 356 case subjects who were diagnosed
with the advanced stage of AMD within 1 year prior to their
enrollment, aged 55 to 80 years, and residing near a
participating clinical center. The 520 control subjects
were from the same geographic areas as case subjects, had
other ocular diseases, and were frequency-matched to cases
according to age and sex.
MAIN OUTCOME MEASURES--The relative risk for AMD was
estimated according to dietary indicators of antioxidant
status, controlling for smoking and other risk factors, by
using multiple logistic-regression analyses.
RESULTS--A higher dietary intake of carotenoids was
associated with a lower risk for AMD. Adjusting for other
risk factors for AMD, we found that those in the highest
quintile of carotenoid intake had a 43% lower risk for AMD
compared with those in the lowest quintile (odds ratio,
0.57; 95% confidence interval, 0.35 to 0.92; P for trend =
.02). Among the specific carotenoids, lutein and
zeaxanthin, which are primarily obtained from dark green,
leafy vegetables, were most strongly associated with a
reduced risk for AMD (P for trend = .001). Several food
items rich in carotenoids were inversely associated with
AMD. In particular, a higher frequency of intake of spinach
or collard greens was associated with a substantially lower
risk for AMD (P for trend < .001). The intake of
preformed vitamin A (retinol) was not appreciably related
to AMD. Neither vitamin E nor total vitamin C consumption
was associated with a statistically significant reduced
risk for AMD, although a possibly lower risk for AMD was
suggested among those with higher intake of vitamin C,
particularly from foods.
CONCLUSION--Increasing the consumption of foods rich in
certain carotenoids, in particular dark green, leafy
vegetables, may decrease the risk of developing advanced or
exudative AMD, the most visually disabling form of macular
degeneration among older people. These findings support the
need for further studies of this relationship.
Hydergine-a new promise
in neuro-retinal disorders.
Shukla, M.
Afro-Asian J. Ophthalmol. 1989; 8(1): 28-30.
No abstract available.
Autofluorescence
characteristics of lipofuscin components in different forms
of late senile macular degeneration]
Spital G; Radermacher M; Muller C; Brumm G; Lommatzsch
A; Pauleikhoff D Augenabtlg. St. Franziskus Hospital,
Munster.
Klin Monatsbl Augenheilkd (Germany) Jul 1998, 213 (1)
p23 31
BACKGROUND: Lipofuscin is the main fluorophore of the
human fundus. Because lipofuscin is the result of the
accumulation of metabolic debris in pigmentepithelial cells
(RPE), the autofluorescence can be interpreted as a
clinical sign for the metabolic activity of the RPE. In
order to get informations of RPE function in different
types of late AMD, the autofluorescence patterns in
patients with late AMD were analyzed.
MATERIAL AND METHOD: A prospective examination of the
fundus autofluorescence of 64 eyes of 52 patients with
different types of late AMD was performed using a confocal
scanning laser opthalmoscope. The autofluorescence images
were categorized in respect to the type of late AMD
according to the opthalmoscopic and fluoresceine
angiographic findings.
RESULTS: Reduced autofluorescence was found in the
centre of occult (78.6%) and classic (100%) choroidal
neovascularisations (NV) as well as in the occult NV of RPE
detachments. A loss of autofluorescence was related to the
RPE free area of RPE tears (100%) and to RPE atrophy
(88.9%) with sometimes increased autofluorescence at the
rim. Increased autofluorescence could be seen at the
surface of RPE detachments (71.4%), in the area of the
shrink age of RPE in RPE tears (100%) as well as at RPE
proliferations in small occult NV (100%). Disciforme scars
showed variable patterns of autofluorescence.
CONCLUSION: The autofluorescence of the RPE can be
analyzed clinically with the described method. Different
patterns of autofluorescence could be revealed in different
types of late AMD. Increased autofluorescence was found in
lesions with proliferative or phagocytotic metabolic
activity of the RPE like RPE detachments, shrinked RPE in
RPE tears or occult NV with RPE proliferations. The reduced
autofluorescence in occult or classical choroidal NV can be
interpreted as a sign of decompensation of the RPE and was
also seen in areas with RPE loss.
Age related macular
degeneration. Can we stem this worldwide public health
crisis?
Starr CE; Guyer DR; Yannuzzi LA Massachusetts Eye and
Ear Infirmary, Harvard Medical School, Boston, USA.
Postgrad Med (United States) May 1998, 103 (5) p153 6,
161 4
Age related macular degeneration, the leading cause of
legal blindness in people over age 60 worldwide, represents
a public health crisis that deserves the attention and
understanding of all physicians. The dry form of the
disease is more common than the wet, but the wet form
causes the most severe vision loss. Other than vision aids
(e.g., glasses, magnifiers), no treatments or preventive
measures are currently available for patients with dry
macular degeneration, and laser photocoagulation with
fluorescein angiography is the only clinically proven
therapy for neovascular disease. Indocyanine green
angiography is a promising new imaging tool that may
improve detection of patients likely to benefit from laser
therapy. Until better diagnostic and treatment options are
available, early screening and patient education offer the
best hope for reducing the widespread devastation caused by
this disease. (32 Refs.)
The development of
neovascularization of senile disciform macular
degeneration.
Teeters, V.W., Bird, A.C.
Am. J. Ophthalmol. 1973 Jul; 76(1): 1-18.
No abstract available.
Treatment of macular
degeneration, according to Bangerter.
Teichmann KD King Khaled Eye Specialist Hospital P.O.
Box Riyadh 7191, Riyadh 11 462 Kingdom of Saudi Arabia
++966 1/482 1234 ++966 1/482 1908.
Eur J Med Res (Germany) Oct 30 1997, 2 (10) p445 54
Age related macular degeneration (AMD) is a common cause
of visual loss among elderly patients. Although some risk
factors have been determined, the ultimate cause of the
disease is not known. For a long time, therapeutic nihilism
has been the rule among ophthalmologists confronted with
such patients. Bangerter has not shared this attitude,
especially since the time that he incidentally discovered,
more than 40 years ago, the beneficial effects of
radiotherapy, in discouraging the growth of new vessels at
the posterior pole of the eye. A variety of approaches are
combined and used by Bangerter in the treatment of the
different types of AMD, including retrobulbar injections of
either vasodilating medications (in the dry or atrophic
type) or corticosteroids (in the wet or exudative type),
general medical measures aimed at improving metabolic and
vascular functions such as supplementation with trace
elements, antioxidants, and vitamins; ozone therapy; advice
to increase physical fitness, improve nutrition, and
abstain from smoking; and protection from excessive light
exposure. Being convinced of the usefulness of his type of
combination treatment, he has always rejected undertaking
controlled clinical trials, of only single aspects of the
therapy, as unethical and invalid. For this reason,
scientific journals have not proven cooperative in several
attempts at publishing his results, as collected in
retrospective surveys. Recently, however, some of the
several approaches combined by Bangerter in treating AMD
have been pronounced effective by other investigators. We
present here an overview of his treatment approaches, as
few people are aware of them, to clear up misconceptions
and to set records straight. (59 Refs.)
Evidence by in vivo and
in vitro studies that binding of pycnogenols to elastin
affects its rate of degradation by elastases.
Tixier JM, Godeau G, Robert AM, Hornebeck W.
Biochem Pharmacol. 1984 Dec 15;33(24):3933-9.
Procyanidol oligomers and (+) catechin bound to
insoluble elastin markedly affect its rate of degradation
by elastases. Insoluble elastin pretreated with procyanidol
oligomers (PCO) was resistant to the hydrolysis induced by
both porcine pancreatic and human leukocyte elastases. The
quantitative adsorption of pancreatic elastase was similar
on either untreated or PCO-treated elastin suggesting that
the binding of this compound to elastin increases the
non-productive catalytic sites of elastase molecules. (+)
Catechin-insoluble elastin complexes were partially
resistant to the degradation induced by human leukocyte
elastase but were hydrolysed at the same rate as untreated
samples by a constant amount of pancreatic elastase. In
addition, the coacervation profile of kappa-elastin
peptides as a function of temperature is greatly modified
in presence of these flavonoids. We conclusively evidenced
that PCOs bind to skin elastic fibres when injected
intradermally into young rabbits. As a result, these
elastic fibres were found more resistant to the hydrolytic
action of porcine pancreatic elastase when injected to the
same site. These in vivo studies further emphasized the
potential effect of these compounds in preventing elastin
degradation by elastase(s) as occurred in inflammatory
processes.
Dynamics of
accumulation and degradation of lipofuscin in retinal
pigment epithelium in senile macular
degeneration]
von Ruckmann A; Schmidt KG; Fitzke FW; Bird AC; Jacobi
KW Institute of Ophthalmology, Universitats Augenklinik,
Giessen.
Klin Monatsbl Augenheilkd (Germany) Jul 1998, 213 (1)
p32 7
BACKGROUND: It is thought that lipofuscin plays a
central role in the pathogenesis of age related macular
degeneration (AMD). The lack of histopathological material
has been a severe limitation in our knowledge on lipofuscin
in this disease. A new technique has been developed that
allows in vivo imaging of fundus autofluorescence derived
from lipofuscin in the retinal pigment epithelium (RPE)
using a confocal Laser Scanning Ophthalmoscope (LSO). We
studied the dynamics of lipofuscin accumulation and
degradation in patients with AMD.
MATERIALS AND METHODS: Serial examinations of the
spatial distribution of fundus autofluorescence were
performed in 148 eyes of 74 patients with AMD using a LSO
over a period of 1 3.5 years.
RESULTS: Fundus autofluorescence changed over time in
almost all eyes studied. Areas of increased
autofluorescence occurred progressively during follow up in
eyes with drusen and hyperpigmentation. The size of
pathologic autofluorescence increased over time in almost
all eyes with geographic atrophy, subretinal
neovascularisations and disciform scars. Irregular
autofluorescence was seen over most subretinal
neovascularisations. Autofluorescence intensity decreased
in old subretinal neovascularisations and disciform scars
over time.
CONCLUSIONS: Changes of the distribution of
autofluorescence occur in eyes with AMD over time. Fundus
autofluorescence imaging allows in vivo analysis of the
dynamics of accumulation and degradation of lipofuscin in
the RPE in eyes with AMD and documentation of metabolic
activity of the RPE.
Cystoid macular
degeneration in experimental branch retinal vein
occlusion.
Wallow IH, Danis RP, Bindley C, Neider M. Department of
Ophthalmology, University of Wisconsin School of Medicine,
Madison.
Ophthalmology. 1988 Oct;95(10):1371-9.
Macular edema and collateral vessels were examined
clinically and histopathologically up to 48 months after
branch retinal vein occlusion in six eyes of five
cynomolgus monkeys. In all six, central macular swelling
and fluorescein leakage from the retinal vasculature were
confined to the acute stage. However, histopathologically,
at the chronic stage, only two maculas were completely
recovered and unremarkable, whereas the other four showed
variable degrees of cystoid degeneration and photoreceptor
cell loss. In the two recovered maculas, six to eight
normal-sized capillaries separated the fovea from the
nearest cluster of capillary collaterals. In three maculas
with cystic degeneration, collaterals incorporated the
circumfoveal capillaries. In the fourth macula with cystic
degeneration, collaterals were separated from the center by
two normal-sized capillaries but were also associated with
large areas of capillary nonperfusion partially due to
occlusion of the macular arteriole.
Study of aging macular
degeneration in China.
Wu LH. Zhongshan Ophthalmic Center, Sun Yat-sen
University of Medical Sciences, Guangzhou, China.
Jpn J Ophthalmol. 1987;31(3):349-67.
Studies of the epidemiology, pathogenetic factors and
visual function of aging macular degeneration (AMD) show
that it has become an ocular disease worth noticing in
China. Although most AMD cases were of the dry type and the
patients had rather good visual acuity, various
determinations of visual function showed different degrees
of impairment. Controlling light exposure and improving
trace metal metabolism may be helpful for early prevention
and treatment of AMD. It will also be an important factor
in the prevention of blindness in Asian nations.
Delayed macular
choriocapillary circulation in age-related macular
degeneration.
Zhao J, Frambach DA, Lee PP, Lee M, Lopez PF. Doheny Eye
Institute, University of Southern California School of
Medicine, Los Angeles 90033, USA.
Int Ophthalmol. 1995;19(1):1-12.
PURPOSE. To investigate the macular choriocapillary
circulation (MCC) in eyes with age-related macular
degeneration (ARMD) and to correlate these findings with
the associated clinical and angiographic drusen
characteristics.
METHODS. Scanning laser ophthalmoscope fluorescein
videoangiography was performed on 34 eyes with age-related
macular degeneration and eight age-matched normal
volunteers. Drusen characteristics were assessed using the
Wisconsin age-related maculopathy grading scale.
RESULTS. A delayed macular choriocapillary circulation
(DMCC) was defined as a macular choriocapillary filling
time greater than 3 standard deviations from the normal
mean (greater than 5 seconds). Nine (26%) of the 34 eyes
with ARMD were found to have a DMCC. After age adjustment,
eyes with DMCC were more likely to have geographic atrophy
of the retinal pigment epithelium (p = 0.003) or choroidal
neovascularization p = 0.07) than were eyes with a normal
MCC. Regional differences in choriocapillary filling times
were present in the eyes with a DMCC, including
nasal-to-temporal, central-to-peripheral, and
inferior-to-superior gradients of progressively less
choriocapillary filling delay. The DMCC correlated with the
location, number, size, confluence, and fluorescein
staining characteristics of the associated drusen.
CONCLUSION. DMCC occurs in some eyes with ARMD. This
finding may not only assist in defining eyes at risk for
progressive disease but may also help to elucidate the
pathogenesis of age-related macular degeneration.
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