It’s getting warmer. I found it when I went swimming recently. Everyone is wearing a swimming cap and goggles. The purpose of wearing a swimming cap is to prevent hair from falling into the pool. So what’s the reason for wearing goggles?
What’s the reason for wearing goggles?
To understand this problem, first put a chopstick in a glass filled with water. Chopsticks don’t look so straight anymore, which proves that light can bend.
The reason for the bending of light is that when light goes from one medium to another, its speed changes – light travels slower in water than in air. The change of speed leads to the change of path and bending. The human eye will make fine adjustments to ensure that light enters through the pupil and focuses on the retina behind the eye. Because we always live in the air, the eye has evolved to take into account the refraction effect at the interface between the air and the eye.
When the eye is in direct contact with water, the adjustment of the eye itself is not enough. When the eye looks at the object in water, the light cannot focus on the retina, so it will become blurred. Wearing goggles restores the path of light from the air to the eyes, so vision will return to normal.
To be sure, if human beings have been living in water for millions of years, the situation will be reversed now. If you want to go ashore, you must wear a goggle filled with water to see the flowers and plants around you.
If you open your eyes in the water without glasses, your eyes will have short-term discomfort or slight pain. After a while, when you get used to it, you can basically see the same thing as wearing swimming glasses. But when you open your eyes after you come out of the water, it will be very painful. It is recommended to wear swimming glasses, because the water in the swimming pool is very dirty and there are bacteria, which will cause damage to your eyes for a long time.
Although many swimming pools will take disinfection measures, but some bacteria and viruses can not be eliminated by disinfection powder. If you do not pay attention to hygiene when swimming, it is easy to cause conjunctival and corneal bacteria infection and eye diseases when the unclean water comes into contact with the eyes;
In addition, when swimming outdoors in summer, the cool water often makes people forget the sun. In addition to sunburn, long-term ultraviolet radiation can also cause burns to the fundus, lens, and cornea, leading to eye diseases.
How to choose swimming goggles?
The most direct and effective way to protect the eyes in a swimming pool is to wear proper goggles to minimize the damage to the eyes. What are the tips for choosing swimming goggles?
1. Optical properties and medical standards
When we choose orthopedic glasses or sunglasses, we will pay more attention to the quality and brand of glasses. In fact, the choice of swimming goggles should be more careful. Because the refractive index of water and air to light is different, if the surface of the swimming lens is uneven, it is like wearing a convex lens or concave lens in water, which will cause damage to the eyes and affect vision for a long time. A good pair of lenses should meet the optical and medical standards, keep the degree of water and underwater unchanged, see clearly without deformation, and have a wide field of vision.
2. Comfort
The design of swimming goggles should follow the principle of ergonomics and conform to the anatomical structure of the human face, head, and eyes. At present, the more popular swimming glasses in the world are smaller, because the eyes of westerners are deeply sunken, and the small glasses are just embedded in the eyes, which is more suitable for the facial characteristics of Westerners. Chinese people generally have flat faces, so it’s more comfortable to choose slightly larger goggles. Generally, the nose bridge and headband of swimming glasses can be adjusted easily, which is suitable for everyone’s needs.
3. Anti fogging performance
Because the water around the goggles is cooler, the air inside the goggles is easy to condense into the water on the inner wall of the goggles, thus causing fog. The swimming mirror with good anti-fog performance has strong hydrophilicity, which can absorb water gas to form water film, which makes water gas unable to attach to the mirror to form fog.
Eyes are the window of the soul, love it, use it to see a more beautiful world, I hope you can always swim healthily!