9 incredible facts about eyes

Everyone heard that the eyes are the mirror of the soul. But that this organ weighs about 8 grams, that brown eyes are actually blue with brown pigment, mostly only ophthalmologists and participants in intellectual quizzes know. We tell you even more amazing things.

Man sees the world around him better than many animals

Biologists from Duke University in the United States conducted an experiment and evaluated Details that look sharp to people may be blurry to their pets vision of about 600 species of insects, birds, mammals, fish and other animals. Research has shown that humans' eyesight is sharper than that of dogs and cats (they see everything in desaturated colors). rats (they see everything blurry and in blue-green shades) and even flies (for them the world is a giant slow motion mosaic). A person is much better at distinguishing small details.

Eye color depends on the amount of melanin

The iris is responsible for the color of our eyes. It contains special cells (chromatophores) containing the pigment melanin, which shines through the cornea.

Its amount determines the color: if there is a lot of melanin, the eyes will be black or brown, if there is little, green or blue. Among humans and animals, red eye color is also found, it happens in albinos. They completely lack melanin, so the color of the eyes is determined by the blood in the vessels of the iris.

Each person's iris is unique

Some people may have similar eye color, but the pattern on the iris never repeats itself, like fingerprints.

Previously, this feature of the iris made it convenient for biometric identification. But in the last decade, an even more reliable method has been invented.

The cornea is even more unique

Although the iris has proven itself to be a unique part of the human eye, authentication against it is not entirely reliable. The fact is that, like the skin at your fingertips, the color of the iris can be changed through surgery. For example, American physician Greg Homer developed Laser procedure can turn brown eyes bluea method of turning brown eyes into blue using laser surgery.

At the same time, Dr. Celia Sánchez-Ramos of the Complutense University of Madrid received the main prize of the Exhibition of Inventions in Geneva, proving La cornea es la parte del cuerpo más fiable para autenticar la identidad de los individuosin his report that it is the cornea that is the most reliable part of the human body for establishing his identity.

Contact lenses were invented much earlier than you think

The first soft contact lenses were released in 1971 Twenty-five years of contact lenses: the impact on the cornea and ophthalmic practice Bausch + Lomb. Now lenses are made from high-tech materials: for example, silicone hydrogel or hypergel. Due to this, they retain moisture well and allow oxygen to pass through.

A prototype of modern contact lenses was discovered among the sketches of Leonardo da Vinci. The scientist empirically found that the optical system of the eye can be improved by contacting the cornea with water. He placed the face of the visually impaired person in a basin of water, and this person for the first time was able to see clearly.

Some more interesting facts about eyes

• Every 12th male is color blind.
• Women blink about twice as often as men.
• Eyeball piercings can be done in the Netherlands. A procedure is performed to implant a precious jewelry, such as a tiny heart or an asterisk.
• It is impossible to sneeze with your eyes open.

The easiest visual acuity test

Look at the sky at night, find the Big Dipper. If in the handle of the bucket near the middle star you clearly see a small one, then you have normal visual acuity. This method of verification was used by the ancient Arabs.

1. Reindel W., Steffen R., Moshauer G. Dry eye digital device users are evaluating new silicone hydrogel contact lenses. Bulletin of Optometry, 2017, No. 3, p. 36−40
2. Rajendra Akaria U., Tang V., Yun V.L., et al. The human eye. Rajendra Akaria U., Ng EIK, Suri J. S., editors. Simulation of the image of the human eye. Norwood, MA: Artek House; 2008:5
3. Steffen R. Schaffer J. Comparison of dehydration of two types of contact lenses. Poster presented at the Global Optical Symposium for Professionals. 01/25/2014 Las Vegas, NV Biotrue® ONEday loses less than 2% moisture in 16 hours of wear.

* There are contraindications. Read the instructions before use.