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Wet age-related macular degeneration.Adv
Drug Deliv Rev. 2005 Dec 13;57(14):1994-2009. Epub 2005 Nov
23.
Age-related
macular degeneration (AMD) is the leading cause of irreversible
visual loss in industrialized nations for those age 65 and above.
The majority of patients with severe visual loss suffer from the wet
form of AMD wherein there is choroidal neovascularization (CNV) and
associated manifestations such as retinal pigment epithelial
detachment, subretinal hemorrhages, and fibrovascular disciform
scarring. The main focus on understanding the pathogenesis of CNV
has been on the hypothesis that the diffuse thickening of Bruch's
membrane predisposes it to develop cracks and in-growth of new
vessels from choriocapillaries with associated low-grade
inflammatory response. Currently, three types of treatments (laser
photocoagulation, photodynamic therapy, and anti-Vascular
Endothelial Growth Factor (VEGF) therapy) have been demonstrated to
limit or delay loss of vision in patients. Only a minority of cases
show stabilization of vision and a small proportion of cases show
significant improvement in vision. This highlights the need for more
and better pharmacologic or other interventions, with the goal of
lowering recurrence rates and preventing the development of CNV in
order to achieve better functional outcomes.
Central corneal
thickness in patients with neovascular age-related macular
degeneration. Cornea. 2007
Feb;26(2):182-4.
PURPOSE: To
compare the central corneal thickness (CCT) measurements of patients
with neovascular age-related macular degeneration (AMD) and control
subjects. METHODS: The CCT value (measured with ultrasound corneal
pachymetry) of 130 eyes (130 patients, 1 eye from each patient) with
neovascular AMD (AMD group) and 98 eyes (98 patients, 1 eye from
each patient) of similar age, sex, and eye's axial length healthy
control subjects (normal group) was compared. RESULTS: The mean age
(AMD group: 69.1 years vs. control group: 69.5 years, P = 0.81), sex
(AMD group: 77 women, 59% vs. control group: 59 women, 60%, P =
0.77), and eye's axial length (AMD group: 25.05-mm vs. control
group: 24.61-mm, P = 0.38) of patients with neovascular AMD and
healthy control subjects were comparable. There were no
statistically significant differences in the mean CCT measurements
in the neovascular AMD group in comparison with the control group
(549.44 vs. 544.35 microm, P = 0.11). CONCLUSIONS: CCT measurements
do not differ in patients with neovascular AMD compared with healthy
control subjects.
Age-related
macular degeneration.Presse
Med. 2002 Aug 24;31(27):1282-7.
EPIDEMIOLOGICAL AND PATHOGENIC DATA: Age-related macular
degeneration (ARMD) is the first cause of blindness in
industrialized countries in patients over the age of 55. Its
prevalence increases with age, affecting up to 25% of the population
aged over 75. The pathogenesis of this disease is not well known.
Not only aging, but also other varying degrees of genetic and
environmental factors are implied. CLINICAL ASPECTS: Precursors
(first clinical signs of ARMD) can be observed on examination of the
fundus: drusen (localized deposits of lipids and lipoproteins) and
alterations in retinal pigment epithelium (RPE) (hypo- or
hyperpigmentation). Two forms of complications are observed:
atrophic (or "dry") and exudative (or "wet"). The atrophic form is
defined by the presence of degeneration in the central RPE,
choriocapillaris and photoreceptors, resulting from the enlargement
and/or coalescence of small areas of peri-foveolar atrophy (or
"geographic" atrophy). The exudative form, responsible for the
majority of cases of blindness due to ARMD, is characterized by the
appearance of choroidal new vessels, identifiable on fluorescein
angiography and responsible for serous retinal detachment, edema and
hemorrhage, leading to the destruction of the macular
photoreceptors. FROM A THERAPEUTIC POINT OF VIEW: Treatment of the
atrophic form is currently only palliative (visual aids and
re-habilitation of low vision). Treatments of the exudative form
having demonstrated their efficacy are laser photocoagulation and
dynamic phototherapy with verteporfine, providing relative
stabilization of visual acuity in around 2/3 of the eyes. Other
treatments are under evaluation: anti-angiogenic treatments,
surgical techniques (ablation of the new vessels, foveal
translocation), new laser treatments (transpupillary thermotherapy,
selective photocoagulation of the feeder vessels). Photoreceptor and
pigment epithelium transplantations or implantation of
microphotodiodes represent other long-term alternatives.
Some aspects
of macular degeneration pathogenesis.
Adv Gerontol.
2006;18:71-5.
Molecular
dehydration is a polyetiologic hereditary determinatory disease.
Variation in the lipid exchange balance resulting in
microcirculation disturbance play an important role in the
pathogenesis of molecular dehydration. Free radical damages in
retina, synthesis activation of nitrogen oxide and cytokines output
cause protein synthesis of apoptosis. Disturbances in apoptosis lead
to molecular dehydration. Study of pathogenesis links of molecular
dehydration gives the possibility to treat this disease.
Aging and
age-related macular degeneration.Zhonghua
Yan Ke Za Zhi. 2006 Mar;42(3):278-82.
Aging is a
common feature of biological changes in the eye, especially in the
retina. It is recognized that the pathogenesis of age-related
macular degeneration (AMD) involves changes of RPE-Bruch membrane
and choroid capillaries complex, which includes function and
structure abnormal in the complex accompanied with aging processes.
Aging may be an important event to contribute to the pathogenesis of
AMD, but aging dose not directly led to the occurrence of AMD,
multifactor is involved in the initiation of the pathogenesis of
AMD. Therefore, this review is summarizing the latest concepts of
the rale of aging in the occurrence of AMD.
The role
of inflammation in the pathogenesis of age-related macular
degeneration.Surv
Ophthalmol. 2006 Mar-Apr;51(2):137-52.
Age-related
macular degeneration (AMD), the leading cause of blindness in the
elderly, is a complex disease to study because of the potential role
of demographic, environmental, and other systemic risk factors, such
as age, sex, race, light exposure, diet, smoking, and underlying
cardiovascular disease which may contribute to the pathogenesis of
this disease. Recently, single nucleotide polymorphisms, DNA
sequence variations found within the complement Factor H gene, have
been found to be strongly associated with the development of AMD in
Caucasians. One single nucleotide polymorphism, Tyr402His, was
associated with approximately 50% of AMD cases. We review recent
developments in the molecular biology of AMD, including single
nucleotide polymorphisms within the Factor H gene, which may
predispose individuals to the susceptibility of AMD as well as
single nucleotide polymorphisms that may confer a protective effect.
Taken together these findings help to provide new insights into the
central issues surrounding the pathogenesis of AMD. |
