Amazing Eye Facts The average person blinks 10,080 times every 14 hours. An eagle can see a rabbit about 1760 yards away but the average human can only see the same rabbit from 550 yards away. The most complex organ in the human body, aside from the brain, is the eye. The eye has over 2 million working parts and processes 36,000 bits of info every hour. The human eye can see a candle 14 miles away, conditions allowing. Eighty five percent of the total knowledge we receive comes from the eyes in a sighted person. The eyeball in a human adult measures 1 inch in diameter but only 1/6 of it is exposed. The external eye muscles are 100 times stronger than necessary. Your eyes use 65 percent of the total pathways to your brain. Nocturnal animals such as the owl have more rods in their retina, because of this they see better in the dark, and their eyes are tubular which increase the light to the lens which goes to the retina. Dogs only see in shades of gray. Fish require no lubricant in their eyes like tears since they are always in water. Fish have no eyelids. Insects have compound eyes. They have many lenses that cannot focus. Their brain takes all these images and makes one image from it. They have a much greater field of view than we do. When an embryo develops, the Pituitary gland develops near the eyes and later in development moves up to the brain. Is this the mythical third eye ? Some animals (reptiles such as some lizards and snakes) have a third eye in the middle of their forehead that detects light, but cannot see. It is used to control body temperature. The sharpest vision belongs to the hawk since it has two foveae and the maximum number of cones. Every year about 40,000 people get a corneal transplant. The oldest person to get one so far was 103 years old. A Raccoon's eyes glow at night because light bounces off a reflector at the back of the raccoon's eye. The reflector doubles the amount of light the eye can use, and helps the raccoon see more at night. Horses and some breeds of dogs cannot see directly in front of them. This is why it is so important to give a horse a loose rein after it takes off for a jump so it can move its head to determine its landing. The mole has the smallest eyes of any animal. The eye of a dolphin has 7000 times as many rod cells as a human eye, enabling it to see in deep water. Some animals such as the Flounder have markings on their body that look like eyes as do some moths. The vulture as a milky membrane over its eyes that serves to keep out bright light and dust. Flies have lots of little holes, where their eyes would be, which are actually hundreds of separate little eyes. Scallops and clams are seen to have 1 to 2 rows of eyes around their shells that enable them to look in every direction and allows them to sense movement but the shells must be open for them to see. The starfish, conch and snail have eyes at the end of their tentacles, this provides them with the ability to poke out a tentacle from behind a shell or other type of protective shelter, without putting its whole self in danger. Nocturnal animals tend to have big eyes, in proportion to the size of their body and pupils that open far wider in low light conditions than those of diurnal daytime animals. Nocturnal eyes gather more light than other eye types do. While we may think something appears completely dark, the nocturnal animal may see it as dimly lit. The flatworm has 2 crude eyes with very limited vision. The octopus has a fairly advanced camera type eye, with an active rectangular iris which contracts to a narrow slit. It can focus its eye lens for near and far vision, but does not have well-defined vision, like humans. Scorpion eye design is really different in that they may have zero to twelve eyes. The average is about eight for most of the common types. The four-eyed fish has a unique eye configuration. Each eye lens has one facet for looking out of the water and another for seeing in it. This complex eye lens can focus two images simultaneously from above and below the water so it is called a four-eyed fish. It must feel very strange to us when we see the simulated vision of some creatures. Take the spider for example. Can you imagine what it would be like to be able to see out of six eyes at once. We think if we have 20/20 vision this is great. It is, but only for us humans. The lowly gecko has vision which is 350 times better than ours. If we look at the eyes of a chameleon, we can’t help but notice the fact its eyes are almost covered except for a pinhole in the center of its round eyelid. The animal is not only able to move its eyes around 360 degrees but move each eye independently of the other. This is a pretty handy feature. A dragonfly has eyes so large they cover most of its head and are so powerful they can see in ultraviolet and polarized light, but they also have three smaller eyes for quick detection of movement. It is not hard to find creatures with better vision than us. Take goats for example. We probably have never thought of their eyesight before, but it is superior to ours. The average human can only see 160 to 210 degrees without moving, but a goat is far more capable. It has a field of vision of 320 to 340 degrees. They even come equipped with night vision due to their large pupils. Does any of this make you wonder what our eyes might be like in the future? Just think if some day eye replacement with creatures who have much better sight than us is possible. There may be people walking around in the future with the eyes of a hawk for example, or maybe scientists might be able to replicate those eyes with some sort of device and install them in us. With all this nature around us that seems superior in many ways to how we come equipped, it would be very tempting for scientists to replicate it.
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