It comes from the coleoid cephalopods, the squids, cuttlefishes, and octopuses. These animals seem to be deaf. Their deafness is so remarkable that it needs to be explained in functional and evolutionary terms.

Researchers said on Thursday that the red brittle star, called Ophiocoma wendtii, is only the second creature known to be able to see without having eyes – known as extraocular vision – joining a single species of sea urchin.

will people go blind from crying too much? No,people do not go: blind from crying too much.

Interestingly enough, in our versatile animal kingdom, there are multiple animals that are born blind. One of them is the eyeless shrimp, which only has light perception. Another one is the star-nosed mole, the fastest-eating mammal in the world, who uses touch as their main sensory organ.

Many species of mammals, such as rabbits, are actually born blind (born with their eyes closed and eyelids fused together), with their eyes opening a little while later.

Totally blind species

• Some moles (the star-nosed mole can detect, catch and eat food faster than the human eye can follow; under 300 milliseconds)
• Sinopoda scurion (blind huntsman spider)
• Thaumastochelidae (blind deep-sea lobsters)
• Blind cave fish.
• Cave crickets.
• Texas salamanders.
• Blind flatworms.

The top 10 animals with the best hearing

• Moth. Recently, moths have been named as having the best hearing in the world, in both the animal and human kingdoms.
• Bat. A well-known trait of the bat is the exceptional hearing they have.
• Owl.
• Elephant.
• Dog.
• Cat.
• Horse.
• Dolphin.

Octopus Eyes The octopus is a rare example of an animal that does not have a blind spot. In an octopus eye, the optic nerve extends from the back of the retina instead of the front, leaving no part of the retina blocked [3].

If you have 20/100 vision, it means that you must be as close as 20 feet to see what a person with normal vision can see at 100 feet. 20/20 vision only indicates the sharpness or clarity of vision at a distance.

20/70 to 20/160, this is considered moderate visual impairment, or moderate low vision. 20/200 or worse, this is considered severe visual impairment, or severe low vision. 20/500 to 20/1000, this is considered profound visual impairment or profound low vision.

If your number is between -0.25 and -2.00, you have mild nearsightedness. If your number is between -2.25 and -5.00, you have moderate nearsightedness. If your number is lower than -5.00, you have high nearsightedness.

When the doctor tests for 20/20 visual acuity he is testing how well your eyes can see an object at a distance of 20 feet. If you can see the letters clearly, then you are considered to have “normal vision.” This number indicates that you can see objects clearly at a distance of 20 feet, compared to other people.

Seeing distances Based on the curve of the Earth: Standing on a flat surface with your eyes about 5 feet off the ground, the farthest edge that you can see is about 3 miles away.

A score of 20/5 means you can see things at 20 feet most people can’t see until they’re standing 5 feet away. This type of visual acuity is akin to an eagle’s vision. There have been reports of an Aborigine man who had 20/5 vision. Despite this, researchers believe this level of vision is not possible in humans.

Eagles. All birds of prey have excellent long-distance vision, but eagles stand out. They can see clearly about eight times as far as humans can, allowing them to spot and focus in on a rabbit or other animal at a distance of about two miles.

As a group, the Aborigines have significantly better visual acuity than the Europeans. This was true for both monocular and binocular vision. Some Aborigines have acuities below the previous postulated threshold levels. Aborigines as a group also have the previous postulated threshold levels.

Here are a few animals and birds which have the best eyesight in the animal kingdom:

• EAGLES AND FALCONS. Birds of prey, such as eagles and falcons, have some of the best eyes in the animal kingdom.
• OWLS.
• CATS.
• PROSIMIANS.
• DRAGONFLIES.
• GOATS.
• CHAMELEONS.
• MANTIS SHRIMP.

Japanese people tend to have the worst eyesight of any national group in the world — it is estimated that over 60% of Japanese wear either contacts or eyeglasses on a daily basis. Other vision problems are common in Japan too. In 2005, researchers found that 1 in 20 Japanese men were colorblind.

A -5 eye and a -7 eye are not much differently at risk, but both are significantly more at risk of retinal problems than a more normal, non-myopic eye. These are rare, though, so no cause for alarm. Just know in advance the signs and symptoms of a retinal tear or detachment if you are very myopic.