http://apologeticspress.org/APContent.aspx?category=12&article=1412
Seeing is Believing: The Design of the Human Eye
If one of your friends asked you, “How do you know God exists?,” what
would you say? There are many different ways to prove God’s existence,
because God has given us so much evidence. Sometimes we find that
evidence in things we see in the Universe, for example, the Sun. The Sun
is like a giant nuclear engine. It gives off more energy in a single
second than mankind has produced since the Creation. It converts 8
million tons of matter into energy every single second, and has an
interior temperature of more than 20 million degrees Celsius (see
Lawton, 1981). Sometimes we find evidence in the animal kingdom. Take
the golden orb spider for instance. Pound for pound, the dragline silk
of this spider is five times stronger than steel, and is twice as strong
as the material that currently makes up SWAT
teams’ bulletproof vests. In fact, due to its amazing strength and
elasticity, it has been said that you could trap a jumbo jet with spider
silk that is the thickness of a pencil.
And sometimes the evidence for God’s existence can even be found within
our own bodies. The writer of the book of Hebrews spoke about this
evidence when he said: “For every house is built by someone, but he who
built all things is God” (3:4).
One of the best examples of design within the human body is the eye.
Even Charles Darwin struggled with the problem of how to explain how
such a complex organ as the eye could have “evolved” through
naturalistic processes. In
The Origin of Species he wrote:
To suppose that the eye with all its inimitable contrivances for
adjusting the focus to different distances, for admitting different
amounts of light, and for the correction of spherical and chromatic
aberration, could have been formed by natural selection, seems, I freely
confess, absurd in the highest sense (1859, p. 170, emp. added).
But even though Darwin acknowledged that the eye could not have evolved, he went on to argue that it had, in fact,
been produced by natural selection through an evolutionary process.
It seems almost as though Darwin could not seem to make up his mind on
the matter. But he is not the only one who has struggled to explain,
from a naturalistic viewpoint, the intricacy of the eye. Evolutionist
Robert Jastrow once wrote:
The eye is a marvelous instrument, resembling a telescope of the
highest quality, with a lens, an adjustable focus, a variable diaphragm
for controlling the amount of light, and optical corrections for
spherical and chromatic aberration. The eye appears to have been designed;
no designer of telescopes could have done better. How could this
marvelous instrument have evolved by chance, through a succession of
random events? (1981, pp. 96-97, emp. added).
How indeed? Though Dr. Jastrow argued that “the fact of evolution is
not in doubt,” he confessed that “…there seems to be no direct proof
that evolution can work these miracles.…
It is hard to accept the evolution of the eye as a product of chance”
(1981, pp. 101,97,98, emp. added). Considering the extreme complexity
of the eye, it is easy to understand why Jastrow would make such a
comment. In his book,
Does God Believe in Atheists?, John Blanchard described just how complex the eye really is.
The human eye is a truly amazing phenomenon. Although accounting for
just one fourth-thousandth of an adult’s weight, it is the medium which
processes some 80% of the information received by its owner from the
outside world. The tiny retina contains about 130 million rod-shaped
cells, which detect light intensity and transmit impulses to the visual
cortex of the brain by means of some one million nerve fibres, while
nearly six million cone-shaped cells do the same job, but respond
specifically to colour variation. The eyes can handle 500,00 messages
simultaneously, and are kept clear by ducts producing just the right
amount of fluid with which the lids clean both eyes simultaneously in
one five-thousandth of a second (2000, p. 313).
Statements like this proves that the eye was so well designed, and so
complicated, that it could not have happened by accident, as evolution
teaches.
THE EYE’S DESIGN
The anatomy of the eye was first examined and recorded at Alexandria, Egypt, in the first century A.D.
An anatomist, Rufus of Ephesus, described the main parts of the eye,
which included the dome-like cornea at the front, the colored iris, the
lens, and the vitreous humor (which gives the eye its shiny look).
Today, thanks to microscopes, we now know that these, along with many
other parts of the eye, work in harmony to produce the gift of sight.
The outer white layer of the eye is called the sclera, more commonly
known as the “white of the eye.” This layer is an extremely durable,
fibrous tissue that extends from the cornea (the clear front section of
the eye) to the optic nerve (at the back of the eye). Six tiny muscles
(known as the extraocular muscles, or EOMs)
connect to the sclera around the eye and control the eye’s movements.
Four of the muscles (known as the rectus muscles) control the horizontal
and vertical movement, while two (the oblique muscles) control the
rotation. All six muscles work together so that the eye moves smoothly.
The inside of the eye can be divided functionally into two distinct
parts. The first is the physical “dioptric” mechanism (from the Greek
word
dioptra, meaning something through which one looks), which
handles incoming light. This includes the cornea, iris, and lens. The
cornea is the transparent, dome-shaped window (about eleven millimeters
in diameter) that covers the front of the eye. Its most important
function is to protect the delicate components of the eye against damage
by foreign bodies. Thus, the cornea acts like a watch face, in that it
lets us look through the “window” of our eye while protecting the
internal components from debris and harmful chemicals. The cornea also
takes care of most of the refraction (the ability of the eye to change
the direction of light in order to focus it on the retina) and works
with the lens to help focus items seen at varying distances as it
changes its curvature. The iris and the pupil work together to let in
just the right amount of light. There are two opposing sets of muscles
that regulate the size of the aperture (the opening, or the pupil)
according to the brightness or dimness of the incoming light. If the
light is bright, the iris constricts, allowing little light to pass; but
if it is dark, the iris dilates or expands, allowing more light to pass
through. The light (or image) then moves through a lens that has the
ability to adjust its shape to help it clarify the image by changing the
focal length of the lens between 40.4 and 69.9 millimeters where it is
then focused (in an inverted form) on to the retina.
Between the lens and the retina is a transparent substance (the
vitreous fluid) that fills the center of the eye. This substance is
important because it not only gives the eye its spherical shape, but
also provides nutrition for the retinal vessels inside the eye. In
children, the vitreous feels like a gel, but as we age, it gradually
thins and becomes more of a liquid.
The second is the receptor area of the retina where the light triggers
processes in the nerve cells. The retina plays a key role in visual
perception. In his book,
The Wonder of Man, Werner Gitt explains how the retina is a masterpiece of engineering design.
One single square millimetre of the retina contains approximately
400,000 optical sensors. To get some idea of such a large number,
imagine a sphere, on the surface of which circles are drawn, the size of
tennis balls. These circles are separated from each other by the same
distance as their diameter. In order to accommodate 400,000 such
circles, the sphere must have a diameter of 52 metres... (1999, p. 15).
Alan L. Gillen also praised the design of the retina in his book,
Body by Design.
The most amazing component of the eye is the “film,” which is the
retina. This light-sensitive layer at the back of the eyeball is thinner
than a sheet of plastic wrap and is more sensitive to light than any
man-made film. The best camera film can handle a ratio of 1000-to-1
photons in terms of light intensity. By comparison, human retinal cells can handle a ratio of 10 billion-to-1
over the dynamic range of light wavelengths of 380 to 750 nanometers.
The human eye can sense as little as a single photon of light in the
dark! In bright daylight, the retina can bleach out, turning its “volume
control” way down so as not to overload. The light-sensitive cells of
the retina are like an extremely complex high-gain amplifier that is
able to magnify sounds more than one million times (2001, pp. 97-98,
emp. added).
Without a doubt, this thin (only 0.2 mm) layer of nerve tissue is a
marvel of engineering. It contains photoreceptor (light-sensitive) cells
and four types of nerve cells, as well as structural cells and
epithelial pigment cells. The two kinds of photoreceptor cells are
referred to as rods and cones because of their shape. Each eye has about
130 million rods and 7 million cones. The rods are very sensitive to
light (whether it is bright or dim), and allow the eye to see in black
and white. Cones, on the other hand, are not as sensitive as rods, and
function only optimally in daylight. There are three different types of
cones—red light, green light, and blue light—each of which is sensitive
to its respective color of light, and which allow the eye to see in full
color. The rods and cones convert the different lights into chemical
signals, which then travel along the optic nerve to the brain.
Not only are the images produced by the dioptric mechanism miniaturized
and upside-down, but it turns out that they also are left-right
inverted. The optic nerves from both eyes split up and cross each other
in such a way that the left halves of the images of both eyes are
received by the right hemisphere of the brain, while the right halves
are received by the left. Each half of the observer’s brain receives
information from only one half of the image. As Gitt went on to explain,
“Note that, although the brain processes the different parts of the
image in various remote locations, the two halves of the field of vision
are seamlessly reunited, without any trace of a joint—amazing! This
process is still far from being fully understood” (p. 17). It is hard to
believe that this inverted system of sight could have been produced
through evolution.
Since the eyes are one of the most important organs in the body, they
must be taken care of constantly. And God designed just such a built-in
cleaning system, consisting of the eyelashes, eyelids, and lacrimal
glands. The lacrimal glands produce a steady flow of tears that flush
away dust and other foreign materials. The tears also contain a potent
anti-microbial agent known as lysozyme that destroys bacteria, viruses,
etc. The eyelids and eyelashes work together to keep dirt and other
debris from entering the eye. The eyelids act like windshield wipers,
blinking 3-6 times a minute to moisten and clean the eye.
For many years, scientists have compared the eye to the modern manmade
camera (see Miller, 1960, p. 315; Nourse, 1964, p. 154; Gardener, 1994,
p. 105). True, the eye and camera do have many things in common, if the
function of the camera demands that it was “made,” does it not stand to
reason that the
more complex human camera, the eye, also must
have had a Maker? Alan Gillen explained it best when he wrote: “No human
camera, artificial device, nor computer-enhanced light-sensitive device
can match the contrivance of the human eye.
Only a master engineer
with superior intelligence could manufacture a series of interdependent
light sensitive parts and reactions” (p. 99, emp. added). That
master engineer was God. The writer of Proverbs knew this when he wrote,
“The hearing ear and the seeing eye, the Lord has made them both”
(20:12).
REFERENCES
Blanchard, John (2000),
Does God Believe in Atheists? (Auburn, MA: Evangelical Press).
Darwin, Charles (1859),
On the Origin of Species (Cambridge, MA: Harvard University Press; a facsimile of the first edition).
Gardner, Lynn (1994),
Christianity Stands True (Joplin, MO: College Press).
Gillen, Alan L. (2001),
Body by Design (Green Forest, AR: Master Books).
Gitt, Werner (1999),
The Wonder of Man (Bielefeld, Germany: Christliche Literatur-Verbreitung E.V.).
Jastrow, Robert (1981),
The Enchanted Loom: Mind in the Universe (New York: Simon and Schuster).
Lawton, April (1981), “From Here to Infinity,”
Science Digest, 89[1]:98-105, January/February.
Miller, Benjamin and Goode, Ruth (1960),
Man and His Body (New York: Simon and Schuster).
Nourse, Alan E., ed. (1964),
The Body (New York: Time, Inc.).
As
America continues her downward spiral into social, moral, ethical, and
spiritual chaos, it is difficult to realize that the first 150 years of
American civilization stand in such stark contrast to current culture.
The Christian orientation of this country from its inception is
irrefutable, revisionist history notwithstanding. The present extensive
transformation of society, and the wholesale abandonment of biblical
principles, are astonishing. If the Founding Fathers could be
resurrected momentarily to observe the change, they would be
unquestionably incredulous. They would be aghast, horrified, and deeply
saddened that America could be so thoroughly redirected toward moral
degradation—a condition that characterized the France of their day.