Eyes evolved millions of years ago (Around 500 million years ago) to help animals sense light and be more aware of their surroundings. Since then eyes have evolved from simple organs being able to distinguish between light and dark to complex systems second only to the brain able to distinguish millions of colors, focus on multiple objects, distinguish shapes and even comprehend depth.
Here are some interesting facts about this amazing organ.
1. Actual Eye vs Visible Eye
Only 1/6th of the eyeball is visible to the world. The rest is inside the body and not visible to anyone. Therefore, what we call eye, is only a small part of the actual eye.
2. Colors we can see
Our eyes can distinguish approximately 10 million different colors! In fact, in just the color grey, our eyes are capable of distinguishing 500 shades of grey. No wonder designers spend so much time to figure out the exact shade of color they want.
3. Complex Organ
Eyes may seem like a simple organ but they have around 2 million working parts, which is highly productive and can adapt to changing environments quickly. This makes it the most complex organ in the human body, second only to the brain. Approximately 80-85% of our learning comes through our eyes.
An average person blinks 12 times in a minute, that is over 10,000 times in a day!! Blinking is important because it clears away dust particles from the eyes and spreads lubricating fluids across the eyeball, preventing eyes from drying out. It also protects eyes from potentially damaging stimuli like bright lights and dust.
5. Eye Muscles
Eye muscles are the fastest and strongest in the body, relative to their function, being 100 times more powerful than actually required. They are also the fastest contracting muscles in the body and can contract is less than 1/100th of a second.
6. Eyes are Unique
Use of bio metrics are becoming increasingly common as use for security purposes. Fingerprints and retina scans are both used for this. However, while fingerprints have only 40unique characteristics, the iris (in our eyes) has 256 unique characteristics, making it significantly more secure than fingerprints.
Tears help to keep the eyes clean and moist. The tear glands are located in the upper eyelid and produce a liquid which is mostly salt and water. Newborn babies, though cry a lot, but their eyes cannot produce tears till they are about 4-13 weeks old.
8. Rods and Cones
The retina of the eye has 2 types of cells that gather light– the rods and cones. Our retina consists of around 120 million rod cells, and 6 million cone cells. Rods are responsible for low light vision and cones for higher light levels.
9. Information Gathering
Eyes are our window to the world. The optical nerve (which contains around a million nerve fibers) transmits the signals to the brain which interprets the signal enabling us to ‘see’ the objects around. It is interesting to note that our eyes focus on 50 different objects every second.
10. Blind Spot
Each of our eyes has a small blind-spot on the back of the retina where the optic nerve attaches. Our brain however uses information from the other eye to fill this gap and therefore this gap is never noticed.