Interesting Facts About Eyes


If you only had one eye, everything would appear two-dimensional!
The purpose of two eyes is to give us 3-D effect-depth perception and wider field of vision on sides.
 

The muscle that lets your eye blink is the fastest muscle in your body!
It allows you to blink 5 times a second. On average, you blink 15 000 times a day.
 

It's impossible to sneeze with your eyes open!
When you sneeze, all your bodily functions stop even your heart.


Cornea is the only part of human body that has no blood supply.
It gets the oxygen supply directly from air.
 

No donor matching is required to transplant cornea!
It is the only living tissue in the human body that does not have any blood vessels. Hence any blood group or HLA matching is not needed.


Babies' eyes do not produce tears until the baby is approximately six to eight weeks old!
 

The retina is the eye's miracle!
This patch, about the size and thickness of a postage stamp of tissue, consists of one million nerve fibers. This forms the main optic nerve which carries visual impulse to the brain.
 

It is possible to tell what someone is feeling by looking at only his or her eyes!
The pupil (the black circle in the middle of the colored iris) may indicate what someone is feeling. Several factors determine the size of the pupil. Primarily, the pupils dilate (get bigger) or constrict (get smaller) to control the amount of light that enters the eyes. In addition, emotions can change the size of your pupils due to the nervous system stimulation. When you experience pleasure, your pupils briefly dilate. Anger and fear can cause the pupils to constrict.
 

Two brown-eyed parents can give birth to a blue-eyed child!
The color of your eyes is determined by the genes you inherit from your parents. A gene for brown eyes is dominant. This means it over-rides genes for other eye colors. The gene for blue eyes is recessive. It shows up only when there are no genes for other eye colors. Someone with brown eyes may have a recessive, or "hidden," gene for blue eyes. Therefore, two brown-eyed parents may each give a recessive gene for blue eyes to their child, who would then have blue eyes. However, you can't necessarily tell a baby's eye color at birth. Often, babies are born with blue eyes, which darken in the first few months of life.
 

My eyes sometimes look red  in a photograph!
If you look directly at the camera during a flash photo, the light from the flash entering your eyes may reflect off the retina, as if reflecting off a mirror. The back of the eye contains many small blood vessels, which give it a reddish appearance. Therefore, the reflected light looks red. Most good cameras have a red eye correction mode or ask the subject to look slightly to the side of the camera.
 

My nose runs when I cry!
The reason why your nose gets runny when you are crying or cutting is because the tears from the eyes drain into the nose. Through out life, the tears are produced from lacrimal gland, form the tear film of eye and drain thru  two tiny  holes on your  inner lid margin and  a thin duct opening in the nose.
 

I sneeze when made to look at a bright light, even when a torch is shined in my  eye!
The "Photic sneeze," a sneeze reflex related to bright light, is not completely understood. As bright light stimulates the retina, it most likely stimulates other related parts of the nervous system. Scientists believe that this stimulation causes nasal congestion, producing a sneeze in some people.
 

Looking at the sun directly can hurt the eyes!
Occasionally glancing at the sun usually does not harm your eyes. However, staring for several minutes at the sun or a solar eclipse can damage visual cells in the part of the retina that allows us to see fine detail. This kind of injury, called solar retinopathy, can cause a blind spot in the center of the field of vision. Loss of vision in these cases can be temporary but often is permanent.


My eyelid occasionally twitches uncontrollably!
Sometimes part of your eyelid may twitch for several minutes or hours. An involuntary twitching of eyelid muscle called Myokymia can occur with stress, lack of sleep or too much caffeine. Occasional twitching of an eyelid usually disappears by itself and does not indicate a serious problem unless it persists or extends to other parts of the face. If it does ,you should seek medical help.
 

I can taste the eye drops put in my eyes!
This happens because the tears or any fluid we put in the eye, gets drained into the nose and throat through two tiny holes on the inner side of our lids.
 

Ever wandered why we see clearly in atmosphere while under water vision is blurry?
The surface of the eye bends light rays, focusing them on the retina and enabling us to see clearly. Light rays bend as they pass from air outside the eye to the fluid within the eye. When someone's eyes are open underwater, the density of the water at the surface of the eye is similar to that of the fluid inside the eye. This decreases the ability of the eye to bend light rays to a focus, and vision is blurry. Wearing a diving mask keeps air in front of the eye, which provides an air-fluid difference and enables the diver to see normally.