What does the UV index of sunglasses mean

It is the level of UV protection. UV1 is protected against wavelengths below 400, and UV2 is protected against wavelengths below 385.

UV400 means 100% UV resistance.

Ultraviolet light refers to the sun's rays with wavelengths between 200nm and 380nm, including three categories: UVA wavelength 315nm 380nm, UVB wavelength 280nm 315nm, UVC wavelength 200nm 280nm. Ultraviolet light accounts for about 13% of the sun's rays (290nm 2000nm) reaching the Earth's surface, of which UVA accounts for 97%, UVB accounts for 3%, and UVC is close to 0.

The damage of ultraviolet rays to the human eye is mainly determined by the wavelength of ultraviolet rays, radiation time and radiation intensity, as well as the strength of the human eye's own defense mechanism, the cornea and lens are the most commonly damaged eye tissues by ultraviolet rays, and solar keratitis and corneal endothelial damage, solar cataract are the most related eye diseases.

Therefore, when we buy sunglasses, we should choose those with the UV400 mark, because this lens can resist the three wavelengths of UVA, B, and C; Ordinary sunglasses can only reduce the luminosity, but cannot block ultraviolet rays. If a pair of sunglasses can only block bright light but not the same amount of ultraviolet light, the wearer will receive more ultraviolet light than without sunglasses (wearing sunglasses will reduce the throughput of the eye entering the person, causing the wearer's pupils to enlarge and cause more ultraviolet rays to enter), further deepening the damage to the eye.

UV-400 : The sunglasses have the "UV-400" logo on them, indicating that the lenses block all UV rays and reflect and absorb 100% of UV rays. The UV400 sunglasses also have the functions of polarizing (even in the strong light at night, without feeling dazzling, and you can see the opposite car clearly) and adding light (it can be as bright as outdoors in the dark).

Lens color: Lens color and UV protection are two different things, even if the lens color is dark, it may not be effective in UV protection, so be sure to choose lenses labeled with UV protection. Usually the UV index of sunglasses is between 96%-98%.

Detection: Generally, regular optical stores will have instruments to detect the ability of sunglasses to resist ultraviolet rays, through this test, you can know whether the glasses in your hand are helpful to your eye health. 3

100% UVA UVB refers to 100% resistance to the harmful rays of UVA and UVB, UVA is a terrible sun killer, which can penetrate the surface layer and penetrate deep into the tissues below the dermis, which can destroy the internal microstructure of collagen, elastic fiber tissue, etc., resulting in wrinkles and fine lines, and sagging and aging.

UVB damage and protection has been thoroughly studied, it can make ** sunburn in a short period of time, redness (for the average person is about 25 minutes), now the vast majority of sunscreen products on the market are UVB type, SPF is a sign of UVB protection ability. In the energy distribution of ultraviolet rays in sunlight, UVA is 15 times that of UVB, which is the main cause of tanning. High-quality sunglasses are completely resistant to UVA and UVB exposure.

The upstairs is more detailed, but there are a few misunderstandings:

1.The main cause of tanning is UVB: after the skin is exposed to the sun, UVB causes the Melanin melanocytes on the surface of the skin to continuously produce melanin, which is transported to the keratinocytes in the epidermis, resulting in a darkening of the skin's complexion.

This pigmentation usually disappears within 1 month.

2.Nowadays, many well-known brands sell sunscreen skin care products that have the effect of blocking UVA and UVB, such as L'Oréal Paris's multi-protection lotion.

The measurement index of UVA is PA: PA+, PA++, PA+++ Although sunglasses can resist ultraviolet rays, after all, they are only limited to the eyes, and it is recommended to use good sunscreen skin care products for sun protection.

UVA UVB is a classification of ultraviolet rays The label on sunglasses should be 100% UV isolated.

UV lenses are mainly used to protect lenses, and have no other use. However, it will have a negative impact on image quality, such as reflection and ghosting or light reduction, so there are high requirements for this lens. It must have an anti-reflective coating

For SLRs, UV lenses only serve to protect the lens. Even if you enter the SLR, the UV mirror can be ignored for money, don't be so entangled, there is nothing worth it, it is purely a personal feeling, you think it is worth it.

Nisi Neji is a Japanese brand that produces filters.。。 uv or something.,It's okay.,I think,At least it's better than the domestic one.。。