[author] [author_image timthumb=’on’]http://wowchasers.com/wp-content/uploads/marija-2.jpg[/author_image] [author_info]Did you know that dolphins sleep with one eye open? Check out Wow insight about eyes, by Maria, doctor and resident of Ophthalmology [/author_info] [/author]
1. All babies are colour blind when they are born.
2. Newborns don’t produce tears. They make crying sounds, but the tears don’t start flowing until they are about 4- 13 weeks old.
3. The eyeball of a human weighs approximately 28 grams.
4. An adult eye has about 24 mm in diameter and about 12 million photo receptors (light sensitive cells) and six muscles that move the ocular sphere with such a precision that it allows the eye to follow moving objects.
5. The external muscles that move the eyes are the strongest muscles in the human body for the job that they have to do. They are 100 times more powerful than they need to be.
6. The eye is the only part of the human body that can function at 100% ability at any moment, day or night, without rest (eyelids and the external muscles of our eyes need rest, the lubrication of our eyes requires replenishment, but our eyes themselves never need rest)
7. Only 1/6th of our eyeball is visible in the outside world.
8. The reason why our nose gets runny when we are crying is because the tears from the eyes drain into the nose.
9. We blink once or twice in 10 seconds. A blink lasts 0.3 seconds. On average, we blink 25 minutes in 12 hours.
10. The retina contains 120 million rods for night vision and 8 million color-sensitive cones for day vision.
11. More than 10 million color hues are detected by human eye, but ultraviolet or infrared light are not detected.
12. The eye can distinguish between 500 shades of gray
13. The cornea is the only living tissue in the human body that does not contain any blood vessels.
14. Our eyes focuses on 50 things in a single second.
15. The eye cannot be transplanted because the optic nerve, which connects the eye to the brain, cannot be reattached once severed. However, the clear front part of the eye called the cornea can be transplanted.
Wow insights about animal eyes:
1. An ostrich’s eye is bigger that its brain.
2. Fish do not have eyelids. They do not require tears either, since their eyes are bathed by water, no special lubricant like tears is required.
3. A chameleon’s eyes can look in different directions at the same time.
4. A worm has no eyes at all.
5. Dogs can’t see the difference between the colours red and green.
6. Zebras can’t see the color orange.
7. The Tuatara is a lizard-like reptile that lives only in New Zealand. The most fascinating aspect of tuataras is their third eye – complete with lens, cornea, rods and nerve tissue connecting it to their brain.
8. Dolphins sleep with one eye open.
9. Snakes always keep their eyes open, even when they are asleep.
10. Honeybees have hair on their eyes.
11. An ant has only two eyes. But each eye contains lots of smaller eyes. This is called a ‘compound eye’.
12. The shark cornea has been used in eye surgery, since its cornea is similar to a human cornea.
13. Crocodiles are color-blind.
14. Owls are the only bird that can see the colour blue.
15. The giant squid, found usually in the deep reaches of the oceans, has the largest eyeball on the face of the earth – 40cm across, it’s about the size of a beach ball.
[learn_more caption=”Source:”] Note:Source: featured photo Suren Manavelyan http://www.surenmanvelyan.com Photo 2 http://bit.ly/T0vfXT 3http://bit.ly/VJZgJN, 4 http://bit.ly/UTLAv5, 5 http://bit.ly/ZzmnxE[/learn_more]