ReMed Magazine | Sciences de la santé
ReMed Magazine Sciences de
la Santé
DIET VITAMINS AND LIFESTYLE
IN AMD PREVENTION
Dr Rachid CHIGARA,
Résident en Ophtalmologie, CHU-Mustapha Pacha
INTRODUCTION
Age-related macular degeneration (AMD), is a degenerative disease that affects the central portion of the retina (mac-
ula). It is the most common cause of visual impairment and may lead to loss of central vision or blindness, affecting
individuals older than 50 years. In the early stages of AMD, patients may be asymptomatic, however, in its advanced
forms the disease may cause serious central vision dysfunction.
The burden of AMD
A
MD is the leading cause of blindness in the de-
veloped world. The prevalence of AMD increas-
es exponentially with age, affecting less than 1%
of the Caucasian population in the sixth decade
of life, 10% of subjects after the age of 80, more
than 15% of the Population in the ninth decade. {1}
In Algeria, AMD is the 4th cause of blindness accord-
ing to a survey conducted in 2009 across the nation-
al territory, ranked after cataract, glaucoma, and di-
abetic retinopathy respectively, with a prevalence
of around 2.1% of the population aged over 50. {15} AMD is a multifactorial and polygenic disease, com-
bining environmental risk factors, lifestyle factors and
genetic factors.
Pathogenesis Smoking
It is currently the most consensually accepted risk
factor, with a dose effect often found in studies. In the
EUREYE study, smokers have a risk of developing wet
AMD 2.6 (95% CI, 1.4-4.8) and 4.8 (95% CI, 2.1-11.1)
for the atrophic form. In the same study, the relative
risk of 1.7 for former smokers {2}
The pathophysiology of age-related maculopathy
is characterized by degenerative alterations involv-
ing the outer retina, pigment epithelium, and Bruch’s
membrane. With advancing age, the pigment epitheli-
um cells become less efficient, thus the retina can no
longer receive adequate nutrients and waste accumu-
lates, leading to deposits called amorphous drusen.
Thus, the cells of the retinal pigment membrane slowly
degenerate, resulting in central vision loss. This form
of slowly progressive disease is called dry type AMD.
Alternatively, if the integrity of the Bruch’s membrane
is lost, choroidal neovascular complexes grow in the
epithelial and subretinal spaces, in a process called
choroidal neovascularization. The new blood vessels
are fragile and incompetent, allowing for leakage and
bleeding, and therefore leading to edema, which com-
promises the integrity of the retina, the macula and
the fovea, and progressively impairs visual function.
The final result is a dense fibrovascular scar, which can
involve the entire macular area. This form of the dis-
ease is called exudative or wet type AMD, accounting
for 90% of cases of severe vision loss in the elderly.
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Risk factors
ReMed
Automne 2017
Age
Population-based studies have demonstrated that of
the risk factors for AMD, age is the first and foremost,
in resource-rich countries, showing that AMD affects
1% of the Caucasian population in the sixth decade
of life, 10% of subjects after the age of 80, more than
15% of the population in the ninth decade. {1}
Alcohol consumption
A meta-analysis published in 2008, analyzing the
results of 5 prospective cohort studies and including
136,946 subjects, shows that alcohol consumption
(more than 3 drinks per day) is associated with a
relative risk of 1.47 (95% CI, 1.10-1.95) to develop
age-related maculopathy. On the other hand some
authors say that small doses of alcohol could have a
protective role on the macula. It would be logical to
think that alcohol can have a protective role in low
dose and a toxic effect in high doses, but studies are
needed to clarify the impact of alcohol on the disease.
Elevated plasma high density lipoprotein
Evidence has been found showing that HDL-cholester-
ol is a causal risk factor for AMD, with an odds ratio
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