THE HUMAN EYE

INTRODUCTION

Our Human body is comprised of many unknown or amazing facts. There are five different sense organs found in the human body. They are

• Eyes – Sight
• Ears – hearing
• Nose – smelling
• Tongue -taste
• Skin – touch

In addition to these five, there are some other senses, which people cannot notice or realize like proprioception, neuron sensors.

Here, let us see some unknown or interesting facts about one of the human sense organs – EYES

HUMAN EYE

Eyes are one of the important parts of every living organisms/beings. Eyes, responds to the light and allows vision. Eyes are the natural tool, which used to recognize the objects or material or things around the world.  Eyes are the most complex organs of the human body next to the Human brain.

FUNCTIONS:

Eyes works like a camera. It has lens, screens.

HUMAN EYE

Image Source : Wikimedia Commons

i) Retina : It is inside the eye which acts as a light sensitive screen in which images are formed. This has Rods and Cones.

Rods : Rods are in charge of detecting shapes, night vision, side vision and for detecting motion. There are 100 million Rod cells, which helps to see the objects better in dark.

Cones : Cones are in charge of colour. There are 7 million cone cells, which helps to see colours and detail.

Rods and cones convert the light from our retinas into electrical impulses/signals and send them to the optic nerve. Further, optic nerve transmits these signals to the visual cortex of the brain. Thus, one visualize.

ii) Cornea : Thin membrane which used as a coverage for eyeball. It is the only tissue in the human body with no blood vessels. Acts like a lens refracts the light entering the eye.

iii) Eye lens : Eye lens are convex lens, transparent and flexible.

Eye lens are jelly like substance.

iv) Aqueous Humour : It is a liquid substance. This fluid is in between cornea and eye lens.

v) Pupil : Pupil is found in the middle of the Iris, where light enters the eyes. Pupil is black in colour since light enters in it and it does not come back.

vi) Ciliary muscles : It is attached with the eye lens. These muscles can modify the shape of eye lens.

vii) Iris : It changes the size of the pupil and controls according to the amount of light passing in to the eye.

viii) Optical Nerve : This transfers the image to the brain in the form of electrical impulses/signals.

Apart from these, yet another and most important function of eye is to secrete Tears. Tears are important for healthy eyes. Tears used for nourishment and lubricates the surface of the eyes. Tears also wash away any debris or dust particles that entered in to the eyes. Tears are comprised of water, oil and mucus.

AMAZING FACTS ABOUT HUMAN EYE

PLASTIC EYE BALLS

• An eye is a collection of 2 million working parts.

• Only 1/6 of the eyeball is exposed or uncovered.

• Eye weighs about 0.25 ounce and is about an inch across.     

• The person is able to learn 80% by eyes.

• A person remembers 80% the things by what he sees.

• Each Eye has a small blind spot and we are not aware of it. Let us test it.

  

  TEST IMAGE FOR IDENTIFYING BLIND SPOT
  

1) Look straight at the image.

2) Close your left eye and focus on the plus sign with your right eye.

3) Look at the plus sign and move slowly your head forward or backward to the image.

4) At certain point you would notice that the disappearance of circle.

5) This happens because of your blind spot.

• Optic nerve constitutes more than one million nerve cells.

• Eyes are the rapid muscle in the human body. That is why we used to say, “In the blink of an eye”.

• A person blinks averagely 12-20 times in a minute. A person blinks more often while talking. Each blinking lasts just 100-150 milliseconds. Scientists estimated a person blinks between 20,000 – 30,000 times per day. A person blinks 42, 00,000 times approximately in a year.

• If the human eye, compared to digital camera it has 576 megapixels.

• Eyes can figure out 10 million unique colours.

• Eyes can heal quickly if properly cared.

• Brown coloured eye is the World’s most common coloured eye.

• Blue-eyed people share common ancestors in the World.

• Person used to see with their brain not with their eyes.

• Eyes become tired, if it not blinked. E.g. while working in the computer, staring at the mobile.

• CVS : Computer Vision Syndrome – specific problem that 50% - 90% of people who work at a computer screen faces.

• Your Eyes or eyeballs remain the same size from birth to death whereas your ears and nose keeps growing throughout your life.

• A person reads approximately 25times faster on paper than on screen.

• Babies are unaware of colours or colour blind at birth.

• Sneezing is impossible by opening the eyes.

• Eyelashes prevent the dirt entering into the eyes. An eyelash falls at an average of 5 months. If all the eyelashes shed by the human in their life lined up, it will be over 98 feet long.

• Newborn babies cries without tears until around 6 weeks old.

• Pupil of the human eye enlarges or expands to about 45 times when you see something you love or fond off.

• Heterochromia is a condition where a person born with two differently coloured eyes.

• 80% of the vision problems are curable and it can be avoided.

• Eyebrows prevent the sweat falling into the eyes.

• The only species known to identify visual hint/cues from other individual eyes are humans and dogs. Dogs do this only while interacting with humans.

  

  
  

  Image Source : Wikimedia Commons

• Now a day’s Retina scans increased for security purposes, because an Iris has 256 unique characteristics, whereas fingerprint has only 40 unique characteristics.

• Fear of the eyes called as Ommatophobia.

• The colour of the eye sometimes appears red in the photos this is due to the blood vessels in the eye.

• Eyes can be sunburned as like the skin. This referred as Photokeratitis.

• Out of all the muscles in the human body, the muscles that control the eyes are most active.

• Half of the brain functionality is dedicated to the eyes for seeing.

• The sensitive part of the eyes is the macula located in the Retina of the eyes.

CONCLUSION

Eyes are one of the very important organs of human body. Keep your eyes healthy and protect from harmful things or injuries. We should limit the exposure of heat, light and dust particles entering into the eyes. Eyes removed within six hours after death. Eye transplantation is quite impossible because more than 1 million nerve fibers connect each eye to the brain. It is too sensitive to reconstruct the optic nerve. Therefore, it is in our hand to protect these complex organs and enjoy the benefits of vision.