Age-Related Macular Degeneration

By Marilyn Haddrill; reviewed by Charles Slonim, MD
Age-related macular degeneration, often called AMD or ARMD, is the
leading cause of vision loss and blindness among Americans who are age 65 and
older. Because people in this group are an increasingly larger percentage of
the general population, vision loss from macular degeneration is a growing
AMD is degeneration of the macula, which is the part of the retina
responsible for the sharp, central vision needed to read or drive. Because the
macula primarily is affected in AMD, central vision loss may occur.
About 1.75 million U.S. residents currently have advanced
age-related macular degeneration with associated vision loss, with that number
expected to grow to almost 3 million by 2020.*
Wet and Dry Forms of Macular Degeneration
Macular degeneration is diagnosed as either dry (non-neovascular)
or wet (neovascular). Neovascular refers to growth of new blood vessels in an
area, such as the macula, where they are not supposed to be.
The dry
form is more common than the wet form, with about 85 to 90 percent of AMD
patients diagnosed with dry AMD. The wet form of the disease usually leads to
more serious vision loss.
Dry Macular Degeneration
Dry AMD is an early stage of the disease and may result from the
aging and thinning of macular tissues, depositing of pigment in the macula or a
combination of the two processes.
macular degeneration is diagnosed when yellowish spots known as drusen begin to accumulate in and around the macula. It
is believed these spots are deposits or debris from deteriorating tissue.
Gradual central vision
loss may occur with dry macular degeneration but usually is not nearly as
severe as wet AMD symptoms. However, dry AMD through a period of years slowly
can progress to late-stage geographic atrophy (GA) — gradual degradation of
retinal cells that also can cause severe vision loss.
No FDA-approved treatments
are available for dry macular degeneration, although a few now are in clinical
large, five-year clinical trials — the Age-Related Eye Disease Study (AREDS;
2001) and a follow-up study called AREDS2 (2013) — have shown nutritional
supplements containingantioxidant vitamins and multivitamins that also
contain lutein and zeaxanthin can reduce the risk of dry AMD
progressing to sight-threatening wet AMD.
But neither the AREDS nor
the AREDS2 study demonstrated any preventive benefit of nutritional supplements
against the development of dry AMD in healthy eyes.
it appears the best way to protect your eyes from developing early (dry)
macular degeneration is to eat a healthy diet, exercise and wear
sunglasses that protect your eyes from the sun’s harmful UV
rays and high-energy visible (HEV) radiation.
Macular Degeneration (neovascular). In about 10 percent of cases, dry AMD
progresses to the more advanced and damaging form of the eye disease. With wet
macular degeneration, new blood vessels grow beneath the retina and leak blood
and fluid. This leakage causes permanent damage to light-sensitive retinal
cells, which die off and create blind spots in central vision.
neovascularization (CNV), the underlying process causing wet AMD and abnormal
blood vessel growth, is the body’s misguided way of attempting to create a new
network of blood vessels to supply more nutrients and oxygen to the eye’s
retina. Instead, the process creates scarring, leading to sometimes severe
central vision loss.
macular degeneration falls into two categories:
New blood vessel growth beneath the retina is not as pronounced, and leakage is
less evident in the occult CNV form of wet macular degeneration, which
typically produces less severe vision loss.
When blood vessel growth and scarring have very clear, delineated outlines
observed beneath the retina, this type of wet AMD is known as classic CNV,
usually producing more severe vision loss.


Your email address will not be published. Required fields are marked *