The Human Eye: Window of the Mind

As I type this article, my wife and I are driving eastward to Charlotte, North Carolina in the eastern part of the United States, and, at this particular moment, we are passing through the beautiful Smokey Mountains. Within the span of a few moments, my eyes collect a diverse host of remarkable images: from broad, sweeping vistas to small and delightful details. At one time, I take in the whole of a mountainous skyline, noting its ragged boundary against the blue sky, as well as the rich shades of green flowing down in thoroughly forested hillsides.

At the far away top of one mountain, I can make out a single branch on a single tree, even its individual leaves. Then, within a moment, I shift my gaze to a beautiful field of golden wildflowers just outside my window. Soon, our car passes into a tunnel, exchanging the world of the very bright for the world of the very dark. Yet, through it all, I see, continually and without interruption, and drink in the scenes of my surroundings.

All of these sights were mine within a few seconds' time, demanding my eyes to adapt almost instantly and automatically to different needs. To do this, the eye requires some of the most intricately designed and coordinated mechanisms in the entire human body.

How It Works

Light enters the eye through the cornea—a hardy, clear, flexible structure at the front of the eye. The cornea exhibits remarkable design that allows it to serve two purposes. First, it is a tough, self-healing structure to withstand the biomechanical stress of its role as a shield for the inner eye, protecting it from debris and pollutants. But it also begins the work of focusing the images coming into your eye, accurately bending the light so that it passes through the pupil, the opening at the center of the iris.

As the eye's gateway, the iris not only gives each of our eyes their distinctive colors—say, blue, brown, or green—but it also has the remarkable ability to precisely and automatically change the size of the pupil, just as the shutter of a camera does, in order to vary the amount of light entering the eye with speed and incredible precision.

Continuing into the eye, the light passes through the crystalline lens behind the iris to complete the focusing process. But, unlike the glass lenses of a camera, the lens of your eye is a flexible, organic structure, which constantly and quickly changes shape as needed in order to perfect its focusing power.

The light, now focused, passes through the transparent vitreous fluid of the inner eye, which simultaneously provides the pressure needed to maintain the eye's round shape, delivers nutrition to the eye's retinal vessels, and acts as a medium for the incoming light to pass undisturbed from the lens onto the retina.

The retina at the back of the eye acts as a projector screen, upon which the image is focused by the cornea and the lens. It is composed of more than 130 million highly sensitive, microscopic retinal cells. These cells vary in type—from rod-shaped cells, which are designed to maximize light processing to help us see in dark conditions, to cone-shaped cells, which are sensitive to color and which also provide for sharp vision and the detection of small details. In fact, there are three types of cone cells, each designed to detect one of the three primary colors of all visible light: red, blue and green. Working in combination, these three types of color-sensitive cells are able to detect virtually any color in the visible spectrum.

When the focused light strikes a retinal cell, a chemical cascade occurs that transforms the light energy into electrical energy, which is then sent through the approximately one million nerve fibers of each eye to your brain, which decodes and interprets the signals into the image you "see."

And all of this is happening constantly at unimaginable speeds! As your eye is continuously flooded with light and images from ever-changing scenery, this system is constantly at work: expertly and automatically moderating the quantity of light entering the eye to optimize for brightness, focusing that light with astonishing precision as it travels through multiple layers of materials and fluids, converting the light photons to electrical signals, and sending them in a code intelligible to the brain so that you can enjoy the blessing of sight.

And yet, the description of the apparatus and machinery of the eye presented here is only a summary. Time would fail us to tell of all the remarkable structures that work together in concert to form the fully functioning eye: the sclera, the extraocular muscles, the choroid, the fovea—the list would go on and on. Suffice it to say that the two small orbs through which the sights around us are harvested for our consumption and consideration are a marvel of design and engineering that no human craftsman has been able to match.

Appearance of Design

As Robert Jastrow, the famous agnostic astronomer and astrophysicist, once said, "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?" (The Enchanted Loom, pp. 96–97).

Jastrow, an evolutionist, was simply paraphrasing and reflecting on the thoughts of Charles Darwin, himself—the originator of evolutionary theory. Calling the eye an organ of "extreme perfection and complication," Darwin had once commented: "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 possible degree" (The Indelible Stamp, ed. J. D. Watson, p. 444)

Still, Darwin reasoned that it might be so, and many evolutionists have struggled to show that his faith in his theory was correct. But even the best explanations they have crafted about how such a marvel as the human eye could have come about through blind, unguided natural processes are, to put it kindly, highly speculative fantasies and oversimplified models based on unfounded assumptions—exhibiting more imagination than evidence.

There is still no satisfactory explanation, apart from the design of an intelligent Creator, for the miracle of engineering we call the eye.

Those eyes—the ones you are using right now to read this article—are the windows to the world that God has crafted for our minds, through which the images of our lives and the glories of His creation continue to shine brightly for our enjoyment and contemplation. And like King Solomon, we too can praise Him for His works: "The hearing ear and the seeing eye, the Lord has made them both" (Proverbs 20:12).