Age-Related Macular Degeneration (AMD) is the leading cause of blindness in
people over 55 years of age, afflicting an estimated 10 million Americans.
The macula is the central region of the retina responsible for central vision.
When the macula is damaged, the result is a loss of vital central or detail
vision. AMD causes sight-sensing cells in the macula to malfunction or lose
function completely.
AMD occurs in two forms, dry and wet. Only your eye care professional can tell
you which type you may have.
With dry (or "atrophic") macular degeneration, the deterioration of the retina
is associated with the formation of small yellow deposits, called drusen, on the
retina and macula, leading to a thinning and drying out of the macula. Central
vision may become blurry and straight lines may appear wavy. Estimates are that
80-90% of all AMD cases are the dry type.
With wet (or "exudative") macular degeneration, vision loss can be rapid and
severe. Abnormal blood vessels grow at the back of the eye. These blood
vessels may then bleed and leak fluid, thus distorting or destroying central
vision. Your eye care professional will discuss with you treatments available
to help stop the progression of wet AMD.
Lutein and zeaxanthin is the short answer. Lutein (again derived from the Latin
luteus meaning golden yellow) is the yellow pigment which gives marigolds their
golden yellow color. In fact, commercial lutein is isolated by solvent
extraction from marigold flowers. Zeaxanthin is another bright yellow pigment
which is chemically almost identical in structure to lutein. Zea is the
scientific name for the genus of corn, and xantho- is the Greek combining form
meaning yellow. Therefore, zeaxanthin is literally the yellow color of corn.
Lutein and zeaxanthin are the pigments which give the macula lutea its yellow
spot appearance. They also are the primary pigments which make egg yolks yellow
since egg producers feed their laying hens both corn and, oftentimes, marigolds
whose zeaxanthin and lutein are concentrated by the hen into the yolks of her
eggs to give them a golden yellow color desired by the consumer.
The intensity of the yellow spot in the eye is proportional to its content of
lutein plus zeaxanthin, and this intensity is known as the macular density.
Macular density progressively decreases as macular degeneration progresses due
to loss of lutein plus zeaxanthin.
Why are lutein and zeaxanthin yellow and why is it important? Blue light is the
shorter wave length and more energetic radiation in the visible range of the
electromagnetic spectrum, and yellow is a longer wave length and less energetic
form of visible light. The chemical structures of both lutein and zeaxanthin are
such that they readily absorb blue light waves but allow the free passage of the
yellow waves, and it is the yellow waves which pass on through to our eyes and
we detect and perceive as the color yellow. The importance lies in the fact that
the structural components of cells are very delicate and can be readily damaged
by the highly energetic blue light waves. Because of their strong absorption of
these damaging high energy blue light radiations, lutein and zeaxanthin help
protect the delicate cellular structures of the retina from this radiation
induced damage which ultimately can destroy vision. The absorption of high
energy blue light can also destroy both lutein and zeaxanthin. Therefore, these
protective pigments must be constantly replaced in the retina.
In reality lutein is a vitamin. Since many of the accessory food factors which
prevent deficiency diseases are amines (a chemical functional group containing a
nitrogen and two hydrogen atoms), these factors were originally designated
"vital amines," i.e. amines necessary for life. In 1912 F.G. Hopkins introduced
the term "vitamin" for these essential dietary factors. Of course, as it turned
out, most vitamins are not amines, but the name stuck. Now the term vitamin
refers to any essential nutritional factor required in small amounts for
maintenance of good health which cannot be made by the body and must be obtained
from the diet.
Lutein can not be made by the human body, and zeaxanthin can only be made from
lutein by our bodies. Therefore, the lutein that we absolutely require for good
vision must be obtained from the diet. Zeaxanthin must be obtained either from
the diet or be synthesized in the body from dietary lutein. Therefore, by
definition, lutein is in reality an essential vitamin. Presently, it is an
undeclared vitamin, but as its importance becomes more recognized it will gain
official vitamin status at some point in the future.
Since we have an absolute requirement for dietary lutein in order to have good
vision, where do we get this important vitamin in our diet? The richest dietary
sources of lutein and zeaxanthin are dark green leafy vegetables such as spinach
and kale. That is why Ocuwel (Click here to learn more
about Ocuwel) is such a good product for the eyes. In three caplets you can
get the equivalent of a one and one-half ounce serving of spinach.
