20 Eye-Opening Vision Facts

Educational, entertaining, and enticing “Did You Know?” tidbits to share with your patients, social channels, and staff


  1. EYE SEE U. A fingerprint has 40 unique characteristics, but an iris has 256. That’s one reason retina scans are increasingly being used for security purposes. ( )
  2. WINKEN ‘N’ BLINKEN. Eyes blink about 12 times a minute, with each blink lasting for about one-tenth of a second. ( )
  3. BEAUTY IS… When attracted to someone, your pupils dilate by as much as 45%. Women with dilated pupils have long been considered attractive. In fact, Italian women in the Middle Ages used belladonna to self-dilate. ( )
  4. SEXY STRABISMUS? The Mayans believed that crossed eyes were attractive and would dangle objects in front of their babies’ eyes until their eyes became permanently crossed. ( )
  5. CLICK, CLICK. If the human eye was a digital camera, it would have 576 megapixels. ( )
  6. THE EYES HAVE IT. An ostrich’s eye is bigger than its brain. A scallop can have over 100 eyes. And, a chameleon can move its eyes in two directions at once. ( )
  7. SHADES OF… E.L. James talks about “50 Shades of Grey.” The human eye can, however, distinguish 50,000 shades of that color. ( )
  8. LOTTA LENSES. A dragonfly has 30,000 lenses in its eyes, helping it detect motion and making the dragonfly very difficult for predators to kill. ( )
  9. LASH LINEUP. Each of your eyelashes has a life span of just five months. If you were able to string together all the eyelashes you shed over the course of your lifetime, they’d measure about 98 feet in length. ( )
  10. FREAKY FACT. Optography was a 19th-century discipline developed to analyze the pupils of murder victims. It was believed that the image of the perpetrator would be photographically impressed into their pupils. Examinations of Jack the Ripper’s victims helped disprove the theory. ( )
  11. THE FLIP SIDE. Your retinas actually perceive the outside world as upside down. It’s your brain that flips the images. Each half of your brain receives half of an image, and then they scramble the images together to compose the whole picture. ( )
  12. ONE ANCESTOR. If your eyes are blue, you reportedly share a single common ancestor with every other blue-eyed person on the face of the earth. ( )
  13. MULTIPLEX. After the brain, the eye is the second-most complex organ in the human body. The eye is home to about 107 million light-sensitive cells and 2 million moving parts that can process 36,000 bits of information every hour. ( ; )
  14. FRANCISCAN FRIAR. The first recorded mention of lenses was in 1263, when friar and philosopher Roger Bacon wrote that lenses are useful for those with “weakness of sight.” ( )
  15. BICEPS, PECS, AND… Work out though you may, your eye muscles will remain the strongest ones in your body. That’s partly because eye muscles are constantly on the move and ever readjusting the position of the eye. There’s not even any rest for the weary, as the eyes continue to move during REM (rapid eye movement) sleep. The eye is, in fact, the only part of the human body that can function at its full ability without any rest. ( )
  16. ELEVEN LINES. Back in the 1860s, Dutch eye doctor Franciscus Donders asked his colleague, Dr. Hermann Snellen, to develop an eye chart to help standardize testing. Before then, every oculist or ophthalmologist had their own favorite chart, which meant the results weren’t comparable from location to location. ( )
  17. WHAT A HOOT. An owl can see a moving mouse more than 150 feet away. In the right conditions and lighting, humans are reported to be able to see the light of a candle from 14 miles away. ( )
  18. BABY BLUES. The first set of blue eyes showed up in the region of the Black Sea between 6,000 and 10,000 years ago. Until then, everyone had brown eyes. ( )
  19. SUPER POWERS. The highest visual acuity on record was that of a male Australian Aborigine whose visual acuity was 6/1.5—meaning he could read an eye chart from 6 meters away as well as someone with “normal” vision could read it from 1.5 meters. ( )
  20. TINTS AND TONES. The human eye can distinguish around 10 million different colors. (Wyszecki, Gunter)

Stephanie K. De Long