We depend on our eyes to find out what is going on in the world around us. While touch and taste require actual contact with things, the eye can receive its sensation at a distance.

Although it is possible to sense odors at some distance, the nose must meet particles given off by the substance we smell. Sound travels through the air; however, the human ear cannot hear at great distances. Only the eye can really conquer distance.

As we age our eyes begin to fail, and eyeglasses are needed to help us see better. Usually, more powerful eyeglasses are needed as we become older. Bifocals are often prescribed, however, distances could be a problem.

Losing my glasses was a frequent problem. One day after searching the house for my glasses, Mary Alice joined the search and after looking in every nook and cranny, she realized they were on her head. However, roles were reversed a few months later when after searching the house, I found her glasses in my coat pocket. Looking for your glasses without wearing a pair, is somewhat like looking up a word in the dictionary without knowing how to spell the word.

The human eye is amazing. The average person blinks once every five seconds or 17,000 times a day or 6 1/2 million times a year.

 I once had 20/20 vision. You might think that this is perfect vision, however it means that the eye can see what a normal eye at 20 feet can see clearly at that distance.

All babies are born with blue eyes. The color of the iris gives the human eye its color. The amount of dark pigment in the iris is what determines its color. In newborn babies, the pigment is concentrated in the folds of the iris. When a baby is a few months old, the melanin moves to the surface of the iris and gives the baby his or her permanent eye color.

Usually, at age 40, the human eye begins to weaken. In the wild, animals do not live long enough to have poor vision, however domestic animals’ vision does weaken. It is not uncommon for a dog to live long enough for its eyesight to become impaired. A person has often been said to have eagle eyes.

This is due to the eagle’s dependence on its eyes to locate food. The eagle, along with all predators, must have excellent vision. Their eyes are placed forward on the head, and in some cases, such as the horned-owl, the eye is fixed and cannot be moved from side to side.

Prey species — animals that are hunted by other animals — have their eyes placed well to the side of their heads. This gives them a wide-range of vision, which almost enables them to see in a 360-degree circle.

Most mammals are colored blind. It is believed that only humans, monkeys, apes and solid-hoofed animals, such as horses, are able to determine color. Birds can distinguish color and use this ability to find food. For example, the hummingbird is attracted to bright colors, especially red. We think of a bull as being attracted to red, but it is only attracted by the movement of the cape, no matter what color it is.

When a young flounder hatches, it is a normally formed fish, with eyes on opposite sides of its head. However, after a short period of time, the body becomes flattened, and one eye begins to move toward the top of the head and continues to move until it becomes close to the eye on the opposite side. The flounder then swims on one side, with both eyes facing up, while watching for food above.

In South America, there is a fish known as a four-eyed. This term is misleading because it has only two eyes, but the eyes are constructed for two types of vision. The eye is divided into an upper and lower part by a dark stripe.

This fish usually swims with its head partly out of the water so that the water surface lies along the dividing line of the eye. The upper half is seeing the objects out of the water, while the lower half is looking around for food beneath the water.

We all know that an animal’s eyes shine at night when a light is put upon them. This was a concern to me one night as I crept under the cover of darkness behind the house of a man who was shooting deer illegally. It seems that he had placed bait in his backyard to attract the deer. Then, every so often, he would step outside with a powerful light and sweep the area, looking for deer. If any were there, he would try to shoot one. That night I had hid in a stand of evergreens and was well concealed, however, when the man swept the light across the yard, the light stopped on my hiding place. I immediately began to wonder if a human’s eyes shine when a light is put on them.

Not taking any chances, I turned my head away, and the man went back inside the house.

Animal eyes shine at night when hit with a light because they have a layer of crystalline substance, which reflects the light. Human eyes have practically none of this substance; therefore, they seldom shine in the dark.

Since this reflective layer aids seeing in the dark, most animals can see better than man at night. The slight variation in the color of the light reflected from the eyes of different animals is partly due to the varied number of blood vessels in their eyes. Eyes containing many blood vessels glow with a definite red color; those with few blood vessels have a whiter glow.

For instance, a raccoon’s eyes will glow yellow, a bear’s eyes are an orange color, a rabbit’s eyes are a ruby red and of course, a deer’s eyes glow white.

Bill Bower is a retired Pennsylvania Game Commission Wildlife Officer. Read his blog and listen to his podcasts on the outdoors at www.onemaningreen.com.