What material protects against ultraviolet radiation. What mistakes do we make when trying to protect ourselves from the sun, and how to fix them

Why is ultraviolet dangerous? When and how should you protect your eyes from harmful solar radiation? Which lenses with UV filter can be bought in our online store?

We begin to think about protecting our skin from the sun only with the advent of its bright summer rays. After all, everyone has heard about the harmful effects of ultraviolet radiation on our health, and many are familiar with medical "horror stories": cancer occurs from it, and wrinkles appear faster. Unfortunately it's true. However, not only the skin, but also the eyes should be protected from the sun's rays, since ultraviolet radiation is also very dangerous for them.

By the way, the position: “I see a bright sun - I remember about UV protection” is not entirely correct. Because there is a type of ultraviolet rays active at any time of the year: UVA (spectrum A rays). And yes, even in the harsh Russian winter, when you can’t see the sun for ¾ days at all, and even on cloudy autumn days.

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Ultraviolet rays are electromagnetic radiation in the spectrum between visible and X-ray invisible radiation, the main source of which for people is the Sun. They come in three ranges, defined by wavelength:

  • near - UVA
  • medium - UVB
  • far - UVC.

The direct threat to people is the rays of the spectrum A and B, since the rays C do not reach the surface of the Earth, being absorbed in the atmosphere. An excess of ultraviolet radiation causes burns of varying degrees in a person, oncological diseases, and premature aging of the skin. For the organs of vision, it is dangerous with such troubles as:

  • lacrimation,
  • photophobia,
  • and in severe cases, corneal burns and retinal damage.

We wrote more about the effects of ultraviolet radiation on vision in.

HOW TO PROTECT YOUR EYES FROM UV LIGHT

To protect your eyes from solar radiation, you can and should use:

  • sunglasses
  • ordinary (corrective) glasses with lenses with a special coating with UV filters (these are, for example, from the Crizal brand and other lenses with multifunctional coatings)
  • contact lenses with UV filters.

Like sunglasses and creams, contact lenses also have several degrees of protection against UV radiation, which are called classes:

  • 99% UVB and 90% UVA are blocked first
  • second class filter protects against 95% UVB and 50% UVA.

On packages of contact lenses with a UV filter, there is a corresponding mark, as a rule, without indicating the class. If necessary, the exact information on the lens protection class can be obtained from the manufacturer.

I would like to note that contact lenses with sun protection are not a complete replacement for sunglasses, but a great addition to them. After all, the lenses do not protect the area around the eyes, do not save from blinding glare and do not increase the contrast of vision, as, for example, polarized glasses do.

Absolutely all contact lenses of the ACUVUE® brand from Johnson & Johnson have UV filters - no other brand can boast such a "breadth" of sun protection in its entire product line. Let's look at a few examples.

Contact lenses 1-DAY ACUVUE® TruEye® - These are soft contact lenses made of silicone hydrogel, a reliable and high-quality modern material. Studies have shown that ACUVUE® TruEye® lenses do not affect the health of your eyes: the condition of the eyes remains exactly the same as before the lenses were worn. [I]

They are great for wearing all day long, even the longest. A fruitful work schedule, then playing sports in the gym or jogging in nature, and after that you plan to drop by for a party with friends? And you are worried whether your lenses will withstand such a rhythm? 1-DAY ACUVUE® TruEye® - will definitely cope with this task! After all, they were specially created for everyone who prefers an active, vibrant and interesting lifestyle.

In addition to a moisturizing component that will not let your eyes feel uncomfortable and dry, ACUVUE® TruEye® lenses have maximum protection against ultraviolet radiation - class 1 filters. Accordingly, they block 99% of UV B rays and block 90% of UV A rays.

The replacement period for these lenses is 1 day. That is, you do not need to take care of their storage and purification. At the end of the day, they just need to be thrown away, and in the morning you will get a new pair out of the package!

lenses ACUVUE® OASYS® and ACUVUE® OASYS® for ASTIGMATISM Designed for two weeks of wear. The unique technology of these lenses - HYDRACLEAR® PLUS - allows you to forget about dryness and keep the lenses moisturized, which means super-comfortable throughout the day. They are suitable for those who spend a lot of time at the computer, with gadgets and in rooms with dry air (for example, in the office). The excellent oxygen permeability of these lenses allows the eyes to breathe freely. A radiant look and constant comfort - what more could you want from lenses?

Of course, safety! ACUVUE® OASYS® and ACUVUE® OASYS® for ASTIGMATISM have a Class 1 UV filter similar to ACUVUE® TruEye® i.e. block over 99% UVB and over 90% UVA .

The advantage of these lenses is that they are more economically priced than disposable lenses. However, scheduled replacement lenses require solutions, storage containers, and some time to care for them.

Contact lenses are a medical product that comes into contact with the surface of the eye, and only a specialist - an ophthalmologist or optometrist - should carry out their selection. Therefore, although the price can be a very tempting argument in favor of purchasing some specific lenses, you still need to focus only on the recommendations of your doctor.

These are beauty lenses for those who do not seek compromises between health and beauty! By emphasizing the natural color of the iris of your eye with their pattern, they make the image brighter, the look more expressive, and you more self-confident! However, ACUVUE® DEFINE® lenses should not be confused with colored lenses, as they do not completely change the color of your eyes. There are 2 versions of these lenses on the market: with a brown tint and with blue. The manufacturer claims that the lenses are suitable for owners of both light and dark eyes.

In addition to charm and comfort, 1-DAY ACUVUE® DEFINE® contact lenses will also give you protection from harmful rays of the sun, thanks to the presence of a Class 1 UV filter. The replacement period is 1 day, which adds points to the treasury of the convenience and comfort of these lenses.

Contact lenses 1-DAY ACUVUE® MOIST® and 1-DAY ACUVUE® MOIST® for ASTIGMATISM also have sun filters. They block 95% of UVB and more than 50% of UVA rays. belong to the 2nd class of protection.

Contact lenses from another manufacturer, BAUSCH + LOMB, are another one-day lenses that will protect your eyes from harmful sun rays - UVA and UVB. They are made of an innovative material - HyperGelTM, combining the advantages of both hydrogel and silicone hydrogel lenses. Excellent oxygen permeability, high moisture content, High DefinitionTM optics - everything in them is designed to make you feel in these lenses as if they were not there before your eyes! 16 hours of excellent vision and comfort - that's what the manufacturer promises us.

You can choose the right sun contact lenses for you in our Ochkarik optics stores. To avoid waiting, we recommend that you make an appointment with a medical specialist in advance.

When writing the article, materials from the following sites were used: jjvc.ru, acuvue.ru, marieclaire.ru, gismeteo.ru, ru.wikipedia.org, bausch.ru.

[I] D. Ruston, C. Moody, T. Henderson, S. Dunn. Daily contact lenses: silicone hydrogel or hydrogel? Optishen, 07/01/2011. Pages 14-17.

Koch et al. Eyes and contact lenses. 2008;34(2): 100-105. Influence of internal moisturizing components of contact lenses on higher order aberrations.

Brennan N., Morgan P. CLAE. Oxygen consumption was calculated using the Noel Brennan method. 2009; 32(5): 210-254. Almost 100% of oxygen is supplied to the cornea when lenses are worn during the daytime, for comparison: this figure is 100% in the absence of lenses on the eyes.

In summer, we spend more time outdoors, wear less clothes at the same time, and our skin is more exposed to solar radiation, which increases the risk of skin damage. Exposure to the skin of ultraviolet radiation is the main cause of the development of malignant neoplasms of the skin, the most malignant of which is melanoma. Over the past 10 years, the incidence of melanoma in Russia has increased from 4.5 to 6.1 per 100,000 population. Every year this tumor affects 8-9 thousand Russians.

It is not always possible to prevent melanoma, but we can significantly reduce the risks of developing this disease.

Protection from the damaging effects of ultraviolet radiation is necessary not only during a beach holiday. Protection is necessary in all situations where you spend a lot of time outdoors, especially during the hours of maximum activity of the sun (from 10 to 16), for example, gardening, boating, various sports, fishing, hiking, mowing the lawn , walks around the city and in parks, cycling.

Protection against UV radiation.

A direct relationship has been proven between exposure to solar radiation and the incidence of malignant neoplasms, including melanoma. Now it is possible to accurately estimate the intensity of solar radiation and the danger of its damaging effects on the skin in a certain place at a certain time. To do this, they are guided by the values ​​​​of the UV index (ultraviolet radiation index), which has values ​​​​on a scale from 1 to 11+ and shows the strength of UV radiation in a particular place. The higher the UV index value, the greater the likelihood of sunburn, skin damage and, ultimately, the appearance of various malignant skin tumors.

  • Protecting the skin with clothing.

If you plan to be in the open sun for a long time, protect your skin with clothing. There is a widespread misconception that any clothing reliably protects the skin from contact with ultraviolet radiation. However, it is not; It is important to pay attention both to the style of clothing itself and to the characteristics of the fabric from which it is made.

Choose clothing that covers your body as much as possible: ankle-length trousers and skirts, T-shirts and long-sleeved blouses.

Dyed, especially with natural pigments (green, brown, beige), or dark clothing protects better from sunlight than white, however, it heats up more, increasing the thermal load on the body. Two-layer materials double their protective properties. Thick clothing is preferred.

Fabrics made of cotton, linen, hemp retain ultraviolet well, but fabrics made of natural silk do not protect against solar radiation. Polyester absorbs ultraviolet as much as possible.

Protect your scalp by wearing a headgear (hat, headscarf). Remember the skin of the ears, they will be protected by the shadow of a wide-brimmed hat. The skin of the neck especially needs protection, this is the least protected part of the body, choose clothes with a collar that can be turned up, or tie a scarf or scarf around your neck.

Remember that clothing cannot provide 100% protection, if light is visible through the fabric, it means that it transmits UV.

  • Use of sunscreen for external use.

Use sun protection products with a sun protection factor (SPF) of 30 or higher. It's a common misconception that sunscreen should only be used on the beach. However, the sun affects us all year round, and during the peak of seasonal activity, the damaging effects of ultraviolet radiation are no less in the city than on the beach.

During the hours of maximum solar activity from 10.00 to 16.00), all exposed skin should be protected by applying a sunscreen. On the beach - on the whole body, in the city or on a walk - on the face, lips, ears, neck, hands. Most people use sunscreen incorrectly, using it too sparingly. The recommended amount of sunscreen per unit of skin surface is 2 mg SPF per cm of skin. For a single application of sunscreen to the skin of an adult, at least 30 ml of the product is required.

Wear sunscreen even on overcast days when the sun is hidden behind clouds, as clouds do not prevent UV radiation from penetrating.

Before applying sunscreen, be sure to read the instructions that come with it, which indicate how often you need to reapply it. On average, it is necessary to repeat the treatment of the skin every 2 hours of exposure to the sun. Many products are not moisture resistant and require reapplication after each immersion in water; increased sweating can also reduce the time of effective protection. Many fans of beach holidays find a certain pleasure in extremely long passive exposure to the sun, they diligently “sunbathe” for hours, in full confidence that they benefit their body, “recover themselves”. This is a very dangerous practice, especially loved by middle-aged and elderly people. Such vacationers should remember that even the competent use of sunscreens does not guarantee absolute protection of the skin from damage, the time spent in the open sun should be strictly limited (no more than 2 hours.).

  • Being in the shade during hours of active sun.

Limiting long exposure to the sun is another way to avoid harmful UV exposure. This is especially true in the middle of the day, from 10.00 to 16.00, when UV radiation is excessively active. A simple test helps to understand the intensity of solar radiation: if a person’s shadow is shorter than the height of the person himself, then the sun is active, and protective measures must be taken. Being in the shade of a beach umbrella is not a complete protection, since up to 84% of ultraviolet rays are reflected from the sand and reach the skin without hindrance.

  • Use of sunglasses.

Paying attention to protecting the skin, do not forget about the eyes. Eye melanoma is less common than skin melanoma. You can reduce the risk of its development only by using special sunglasses. It is better to use large-diameter glasses, the glasses of which block at least 98% of ultraviolet rays. Buy glasses from specialized optical shops, make sure that their lenses absorb UV up to 400 nm, which means that the glasses block at least 98% of UV rays. In the absence of such instructions on the label, the glasses most likely will not provide sufficient protection for the eyes.

By protecting yourself from the damaging effects of ultraviolet radiation, you prolong life.

For many people, sunglasses are an everyday accessory that allows you to emphasize style and create the look you want. However, we should not forget that these optical products perform another important function - protecting the eyes from ultraviolet radiation. Consider what determines the degree of blocking of UV radiation in sunglasses.

Currently, there is a wide range of sunglasses on the market for ophthalmic products. The range is replete with the presence of popular brands, a variety of shapes, designs and colors. However, when buying eyeglass optics, you need to take into account not only the decorative component, but also the protective properties of the lenses. It is important that the corrective agent provides the necessary level of protection of the organs of vision from the harmful effects of ultraviolet rays.

Many are interested in how to choose sunglasses according to the type of protection. We propose to look into this issue.

Should you protect your eyes from UV light?

To understand whether it is worth protecting your eyes from exposure to sunlight, you need to understand their types, the nature of their appearance and the impact on the human organs of vision. Up to 40% of the radiation is categorized as visible and allows us to distinguish colors. About 50% of the sun's rays are infrared. They make you feel warm. Finally, 10% of the sun's rays are ultraviolet radiation, invisible to human eyes. According to the wavelength, it is divided into several subcategories (long-wave - UVA, medium-wave - UVB, and short-wave - UVC).

Types of ultraviolet radiation:

  • UVA - is in the range of 400-315 nm. Mostly reaches the surface of the Earth;
  • UVB - is in the range of 315-280 nm. Mostly delayed by the atmosphere, but partially reaches the surface of the Earth;
  • UVC - is in the range of 280-100 nm. It practically does not reach the Earth's surface (it is delayed by the ozone layer).

Do you need goggles to protect your eyes from UV rays?

Ophthalmologists say that in moderation, ultraviolet is good for the body, as it helps to strengthen the immune system, increase body tone, and even improve mood. Under the influence of UV rays in the eye, metabolism and blood circulation are stimulated, and muscle function improves. In addition, the body produces vitamin D, which strengthens the musculoskeletal system, and produces histamine, a substance that has a vasodilating effect.

However, with intense exposure, ultraviolet rays have a detrimental effect on the body, including the organs of vision. The lens captures long-wave UV radiation, gradually losing transparency and acquiring a yellowish tint. Experts recommend paying due attention to protecting the eyes from ultraviolet radiation, since clouding of the lens leads to the development of such a serious disease as cataracts. In 50% of cases, in the absence of timely treatment, this eye disease is the cause of blindness. The mucous membrane of the eye and the cornea absorb medium-wavelength ultraviolet radiation (UVB), which can significantly damage their structure under intense exposure. The use of sun protection avoids this problem.

To correctly approach the purchase, you need to decide what kind of UV protection sunglasses should have. This factor should be given priority when purchasing these products.

Why you should protect your eyes from intense ultraviolet radiation:

  • The lens captures long-wave UV radiation, gradually losing transparency and acquiring a yellowish tint. This can lead to the appearance of cataracts;
  • The cornea absorbs medium-wave ultraviolet (UVB) radiation, losing its optical properties.

How much protection should sunglasses have?

Many people do not know how to determine the protection of sunglasses and mistakenly believe that the darker the lenses, the better they block UV rays. However, it is not. Clear lenses can absorb harmful radiation just as well as dark lenses if they are coated with a special coating. Moreover, the pupil under dark lenses dilates, so in the absence of a filter, ultraviolet rays are easily absorbed by the lens.

Products from world famous brands without fail have a special marking that characterizes the degree of protection. Spectacle optics marked "UV400" are considered to be of the highest quality. It filters up to 99% of UVA category ultraviolet with a wavelength of up to 400 nm. However, it should be borne in mind that with the systematic wearing of such glasses in the summer, a “mask” forms on the face, since the skin around the eyes does not tan. Much more common are products labeled UV 380, which filter only 95% of UV rays. Inexpensive products provide blocking from 50% of radiation. All products that capture less than 50% of UV rays do not protect the eyes from their negative effects. Often they are used only for decorative purposes.

Sometimes there is a label that indicates the degree of protection from UVA and UVB rays at once: “Blocks at least 80% UVB and 55% UVA”. This means that the filter applied to the surface prevents the penetration of up to 80% of UVB rays and up to 55% of UVA rays. Doctors advise choosing products where both indicators are above 50%.

In addition, there is another option for marking glasses:

  • cosmetic. Optical products that block less than 50% of UV radiation. These glasses are not recommended for use on sunny days, as they do not protect the eyes from the sun;
  • General - universal products with UV filters that block from 50 to 80% of UV rays. Such glasses can be used for everyday eye protection in the city, at mid-latitudes;
  • High UV-protection - models with enhanced UV filters that block almost 99% of ultraviolet radiation. They can be used on a bright sunny day in the mountains, near the water, etc.

How to choose sunglasses according to the degree of darkening?

After you have decided on the degree of protection of glasses from UV radiation, you need to choose the level of their light transmission, or darkness. This parameter will determine how brightly you can perceive the world around you. As a rule, such marking is located on the temple of glasses and consists of two components: the name of the model and the darkness index, for example, “Cat. 3" or "Filter cat. 3".

Classification of sunglasses by darkness:

  • Marking (0). This product is almost completely transparent. It transmits from 80 to 100% of visible sunlight. Such glasses are recommended for use by athletes when exercising in the absence of bright light.
  • Marking (1,2). This optics has a light transmission from 43 to 80%, as well as from 18 to 43% of the light, respectively. This is the best option for wearing in low and medium solar radiation.
  • Marking (3,4). These glasses should be used in very bright sunlight.

In the hot summer period for our latitudes, optical products with 2 and 3 degrees of light transmission will be the best choice. For use on summer mornings, as well as in spring and autumn, models with 1-2 degrees of dimming are suitable. Points with an indicator of 4 are recommended for travelers in extreme conditions, for example, when conquering mountains.

It should be clarified once again that the degree of darkening has nothing to do with protecting the eyes from the adverse effects of ultraviolet rays. This indicator affects only the brightness of the image perception and the comfort of wearing optical products.

What else can protection glasses have?

Modern manufacturers of sunglasses make sure that their products are as comfortable, practical and durable as possible. Therefore, in addition to the UV filter, additional coatings are often applied to the surface of products.

  • Polarizing filter. Fully blocks glare - rays reflected from horizontal surfaces (water, snow-covered field, car hood, etc.);
  • Anti-reflective coating. Cuts off some types of sun glare, increasing the comfort of use;
  • Mirror finish. As a rule, it is applied to one degree or another on all glasses. Reflects visible sunlight, providing extra comfort to the eye;
  • Abrasion resistant coating. Increases the resistance of spectacle lenses to the appearance of mechanical damage (scratches, cracks, etc.);
  • Melanin spray. It is applied to the inside of the lens to prevent eye fatigue.
  • Gradient coverage. Allows you to increase safety while driving. The upper, darker part of the lens provides good visibility when looking at the road. In turn, the light bottom of the lenses contributes to a good overview of the dashboard.

We recommend that you familiarize yourself with a wide selection of glasses and contact correction products on the website. We offer you high quality products from world brands at competitive prices. With us you can easily place an order and receive the goods in the shortest possible time!

Visible radiation - electromagnetic waves perceived by the human eye are approximately in the wavelength range from 380 (violet) to 780 nm (red). What is to the right of the visible spectrum, i.e. with a wavelength of more than 780 nm, is invisible to humans, infrared (IR) radiation. To the left, i.e. with a wavelength from 250 to 400 nm, there is that part of the spectrum invisible to man that interests us today - ultraviolet (UV). Under the influence of ultraviolet radiation (UV), the eyes, skin and immunity suffer. In ordinary life, direct sunlight does not enter the eyes, especially when the sun is at its zenith, but due to reflections from surfaces, it is believed that 10-30% of the radiation (depending on external conditions) that reaches the earth's surface ends up in the eyes. In the case of paragliders, when pilots have to raise their heads to the sun, direct rays also hit. For winter sports (skiing, snowboarding, kite, etc.), as well as for water activities (kite, surfing, beaching, etc.), the amount of reflected radiation entering the eye is above average.

According to the wavelength, UV radiation is divided into 3 components: UVA, UVB and UVC. The shorter the wavelength, the more dangerous the radiation. UVC, the shortest and most dangerous range of ultraviolet radiation, fortunately does not reach the earth's surface thanks to the ozone layer. UVB - radiation in the range of 280-315 nm. Approximately 90% of UVB is absorbed by ozone as well as water vapour, oxygen and carbon dioxide as sunlight passes through the atmosphere before it reaches the earth's surface. UVB in low doses causes sunburn, in high doses it burns and increases the chances of skin cancer. Too much UVB exposure to the eyes causes photokeratitis (sunburn of the cornea and conjunctiva, which can lead to temporary loss of vision (severe photokeratitis is often referred to as "snow blindness"). The risk of photokeratitis increases in high altitudes and also in snow if the eyes are not protected It should be noted that the impact of ultraviolet radiation in the UVB range is limited to the surface of the eye, these ultraviolet rays practically do not penetrate into the eye.

Ultraviolet radiation in the UVA range (315-400 nm) is close to the visible spectrum, in the same doses it is less dangerous than UVB radiation. But these ultraviolet rays, unlike UVB, penetrate deeper into the eye, damaging the lens and retina. Long-term exposure to UVA in the eyes increases the risk of a number of dangerous eye diseases, including cataracts and macular degeneration, which is considered the main cause of blindness in old age. Let's also mention the part of the visible spectrum corresponding to the blue rays of the visible spectrum, about 400 -450 nm, (HEV "high-energy visible light"), which is directly adjacent to the long-wavelength part of the UV range. It is assumed that prolonged exposure to these high-energy visible spectrum rays on the eyes is also harmful, since they penetrate deep into the eye and affect the retina.

The damaging effect of ultraviolet rays on the eyes depends on a number of factors:

  • Length of stay outdoors
  • Geographic latitude of the location. The equatorial zone is the most dangerous
  • Height above sea level. The higher, the more dangerous
  • Time of day. The most dangerous time is from 10-11 am to 14-16 pm
  • Large surfaces of water and snow, highly reflective of the sun's rays

Thus, the constant action of ultraviolet radiation on the eye has a harmful effect on the surface of the eye and its internal structures. Moreover, negative effects are cumulative: the longer the eyes are exposed to the damaging effects of ultraviolet radiation, the higher the risk of developing pathologies of the structures of the eye and the occurrence of age-related diseases of the organ of vision.

Sunglasses are one way to limit the amount of harmful radiation reaching your eyes. Because lifetime doses of UV exposure accumulate, increasing the risk of eye disease, it is recommended that sunglasses be worn regularly outdoors.

Measurements and results

Characteristics of lenses and concepts that we will need when analyzing tests and measurements: Optical density. This is the decimal logarithm of the ratio of the intensity of the incident radiation to the transmitted one. D=lg⁡(Ii/Io) if the optical density of the lens is 2, then it reduces the radiation intensity by a factor of 100, delaying 99% of the incident radiation. If D=3, then the lens blocks 99.9% of the radiation. In addition, sunglasses lenses are divided by transparency (for the visible spectrum):

  • Transparent F0, 100 - 80% light transmission used at dusk or at night, sports and goggles against snow and wind;
  • Light F1, 80 - 43% light transmission, cloudy goggles;
  • Medium F2, 43 - 18% light transmission, used in partly cloudy;
  • Strong F3, 18 - 8% light transmission, to protect against bright daylight;
  • Maximum strength F4, 8 - 3% light transmission, for maximum protection in high mountains, ski resorts, in the snowy arctic in summer. Not designed for driving.

For measurements we have a spectrophotometer:

Several glasses and lenses from different manufacturers were chosen at completely different prices. The cost of glasses ranged from 1 to 160 Euros (70 -11,000 rubles). So, let's start from expensive to cheap: The first 2 lenses are GloryFy, brown F2 and gray F4. Glasses of this brand with such lenses cost about 11,000 rubles.

Graph of transmission in %, i.e. what percentage is the intensity of the transmitted radiation from the incident:

Red represents the transmission of the brown F2 lens and blue represents the transmission of the gray F4 lens. As can be seen from the graphs, both lenses cut all ultraviolet well. In addition, it can be seen that the brown F2 lens cuts the blue part of the spectrum much better, the gray F4 is essentially neutral (i.e., does not distort colors) and, being darker (F4 versus F2 for brown), darkens more strongly in the entire spectrum. For a more accurate assessment of how well ultraviolet radiation is blocked, here is a graph of optical density for these lenses:

red line for brown F2 lens and blue line for gray F4 lens

It can be seen that the optical density is greater than 2.5 over the entire ultraviolet range, i.e. more than 99% of the ultraviolet incident on the lens is blocked. To clarify, I will give the values ​​for these lenses for a wavelength of 400 nm. Optical density for gray F4 D=3.2, for brown F2 D=3.4. Or the transmission from incident radiation for gray F4 is 0.06%, and for brown F2 it is 0.04%.

Move on. Here we have graphs of transmission and optical density for glasses of the middle price category: Smith and Tifosi - both lenses are gray, dark. The cost of glasses is about 4000-6000 rubles. And cheap glasses costing about 700 rubles, - 3M and Finney - both lenses are also neutral, i.e. grey, dark. To begin with, the transparency for all these mentioned lenses

It can be seen from the graphs that all lenses of category F3. In addition, it is noticeable that the lenses of cheap glasses (3M and Finney) cut the near ultraviolet, UVA in the range of 385-400 nm worse. Now for all these 4 points we give the transmission value at a wavelength of 400 nm:

  • Smith T=0.002%
  • Tifosi T=0.012%
  • Finney T=5.4%
  • 3M T=9.4% and optical density at the same wavelength:
  • Smith D=4.8
  • Tifosi D=3.9
  • Finney D=1.26
  • 3M D=1.02

It is clear that cheap 3M and Finney glasses do not meet the requirements of UV400 protection. They begin to protect normally from a wavelength of 385 nm and below.

But we have the cheapest glasses, unbranded (Auchan glasses). The cost is 70 rubles or 1 euro. The lens is yellow, in terms of transmission it seems that the category is F1. Transparency:

Optical density:

For a wavelength of 400 nm, the transmission was 0.24%, and the optical density was 2.62. This lens meets the requirement for UV400.

Findings:

It can be seen that cheap glasses do not have a stable quality of protection: 2 out of 3 samples were not satisfied. Branded glasses of the upper and middle price categories did a good job of protecting against ultraviolet radiation. In addition, when we talk about UV protection with glasses, it should be taken into account that light can also penetrate from the side of the frame, therefore, of course, glasses that cover the entire field of vision and prevent light from entering the eyes past the lenses of the glasses are better protected. And of course, when choosing glasses, one should take into account how comfortable they sit on the face, because they have to be worn for hours. For people involved in active sports and frequent travelers, it is important how durable the glasses are: it is unpleasant to find fragments in the backpack instead of glasses at the right time.

2 chose

When summer is in the yard, products with SPF against UVR, as well as "defenders" from UVA/UVB. But what are these mysterious abbreviations and what is the meaning of each of them? Let's figure it out!

UVR- the simplest of all the abbreviations presented, which means Ultra Violet Radiation - ultraviolet radiation.

IPF- Immune Protection Factor - immunoprotective factor. This is an effective protection of Langerhanz cells and other internal skin structures from solar radiation. Scientists are also studying the properties of antioxidants such as green tea, grapes and grape seed oil for further use as free radical scavengers.

SPF- the most popular "set of letters" - Sun Protection Factor. Sun protection factor, which indicates the degree of protection against ultraviolet rays. SPF "informs" how many times your usual time in the sun can increase before the skin begins to "burn". The higher the SPF, the more protection. UVA protection is harder to determine because they don't cause pain or redness. Therefore, in this case, coefficients are applied that determine the so-called pigmentation - permanent (PPD) or instant tan (IPD).

UVA- long-wave (320–400 nm) ultraviolet rays of group A, which reach the surface of the earth all year round and even pass through clouds. They make up 95% of all ultraviolet radiation that hits the Earth. It is important that the radiation is able to penetrate window and car glass. Its "strength" does not depend on the time of year or time of day. It reaches the dermis, acting directly on fibroblasts and other skin cells, and, above all, damages collagen fibers. It has also been proven that under the influence of UVA rays it can lead to changes in DNA and the occurrence of mutations. The main consequences of exposure to UVA radiation include photoaging of the skin and the development of cancer. This is a good reason to remember to use UV filters all year round.

UVB- medium-wave (280-320 nm) ultraviolet rays of group B, which act painlessly, but penetrate the skin so deeply that they reach the cells of the dermis. They represent 5% of the UV radiation that reaches the Earth's surface. Its intensity increases from 10 am to 3 pm, especially in summer. Does not penetrate window glass and clouds, but easily penetrates through water. It is responsible for redness and burns, allergies that occur on the skin after sunbathing, as well as for the development of tumors (melanoma).

UVC- ultraviolet rays of group C, which have the shortest waves - 100-280 nm. They do not reach the Earth's surface due to the ozone layer.

How to choose the right filter?

In order to protect the skin of infants and young children, the use of physical filters that do not absorb into the skin is recommended. Chemical filters can cause allergies, irritation or dermatitis. An alternative is cosmetics containing chemical filters designed specifically for the sensitive skin of children. In addition, all products in this category regularly undergo special tests. For babies, we recommend products with a minimum SPF 30 filter in our climate. For babies, the filter should be SPF 50. Be sure to use a moisturizer after sunbathing.

PhototypeI- very fair skin, freckles, red or blond hair, skin easily burns, rarely tans (it is recommended to use creams with an SPF of at least 30),

Phototype II- light skin, few freckles, light hair, skin easily burns, tans with difficulty (SPF at least 20),

Phototype III– dark skin, no freckles, brown hair, fairly resistant to burns, tans very easily (SPF 12-15),

Phototype IV– very dark skin, no freckles, dark brown or black hair, skin does not burn, always tans very well (SPF 8-10).

How to apply creams with a filter?

  • Cream with a filter is applied to the skin at least 20 minutes before leaving the house;
  • Apply the cream every 2.5 hours and renew it after every bathing, perspiration and if you towel dry;
  • Try not to sunbathe during the day (especially in the early days of summer, when the dose of sunlight is the most intense).