Nature Had It First

“The hearing ear and the seeing eye​—Jehovah himself has made even both of them.”​—Proverbs 20:12.

YOUR eyes are like tiny television cameras. They convert images into electrical signals and transmit these signals along the optic nerve to the back of your brain, where the actual seeing takes place.

The eye is a marvel in miniature. Just an inch [24 mm] in diameter and one fourth of an ounce [7.5 g] in weight, it is ingeniously engineered. For example, it has separate systems for dim and bright lighting, so that 30 minutes after entering a dark room, your eyes may become 10,000 times more sensitive to light.

In normal lighting, what gives you a clear picture? Your eye has over 100 times more light-sensitive cells (pixels) than most video cameras. Also, a large portion of those cells are packed into a small spot at the center of the retina called the fovea, which provides the sharpest vision. Since you shift your gaze several times a second, you get the impression that your whole field of vision is sharp. Remarkably, your eye’s fovea is about the size of the dot at the end of this sentence.

Electrical signals from the light-sensitive cells pass from one nerve cell to another toward the optic nerve. But the nerve cells do more than just pass the signals on. They preprocess them, enhancing vital information and suppressing unneeded detail.

The visual cortex of your brain is like a sophisticated video receiver. It sharpens images by enhancing edges and compares the signals from cells sensitive to primary colors, so you can distinguish millions of colors. Your brain also compares the tiny dissimilarities between what your two eyes see, so you can perceive distance.

Consider how your eyes scan faces in a distant crowd and send electronic impulses to your brain, which then transforms the signals into clear images. Consider, too, how subtle details of those faces are compared with ones in your memory, so that you instantly recognize your friend. Is that process not awe-inspiring?

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The way the eye processes information attests to its ingenious engineering