Eye Diseases 161Because, as primates, depth perception is critical to our survival,
nature strengthened our central vision by placing our eyes close
together. However, we developed strong central vision at the expense
of our peripheral vision. The macula, as the visual center of the eye and
therefore the most active part, is for that reason more vulnerable to
injury than the periphery of the retina or any other part of the eye. It’s
therefore not surprising that while in glaucoma the retina in the back
of the eye is damaged from pressure due to the buildup of waste-fi lled
fl uid in the front of the eyeball, in macular degeneration, the macula
triggers its own deterioration.How Macular Degeneration Develops
In macular degeneration, vision becomes blurred because as normal
cells and tissue in the macula in the back of the eye are lost or disinte-
grate, inappropriate tissue (blood vessels and alien molecules) move in
to take their place. These abnormal and misplaced cells injure the
macula by causing scar tissue to form. Scar tissue blurs vision because
as light rays focus on the scarred macula they are bent out of shape.
The blurring of the vision increases when the insulating layer between
the macula and the blood vessels behind it breaks down. Leftover fl uids
from this breakdown leak into the macula and cause additional scar-
ring. In the meantime, a yellowish substance called drusen fi lls in the
space behind the macula where the insulating layer had once been.
This blocks the macula from the blood vessels that supply it with oxy-
gen and nutrients. When blockage has completely cut the macula off
from the nutrients and oxygen it needs to function, the more serious
form of macular degeneration, the “wet” version, sets in. In an effort
to supply the deprived macula with oxygen, a blood vessel inducer
called VEGF stimulates the growth of blood vessels inside the macula.
Probably because they don’t belong there these blood vessels rupture
and bleed. Scars grow over the ruptured spots, and this increases the
blurring of the macula’s central vision, often making it impossible to
see images.
In an effort to stem the loss of vision in macular degeneration, medi-
cal researchers have tried to prevent the growth of blood vessels in the
macula by destroying VEGF, the blood vessel inducer. Why don’t these
researchers instead try to fi nd a way to detoxify the area behind the