Sunglasses. General technical requirements. Sunglasses Eye protection features

There are European, American, Australian quality requirements for sunglasses (OTC).

Standardization goes in two directions:

Safety:

• the quality of the material from which the frame is made (non-toxic in contact with skin, non-flammable);
• quality of processing (grinding and polishing) of lenses;
• impact resistance;

Efficiency:

• the degree of transmission of UV rays.

What are ultraviolet rays (UV)

Ultraviolet radiation UVR is the invisible part of the spectrum, measured in nanometers. 1 nm = one billionth of a meter (10 to the -9th power).

Depending on the wavelength, there are:
UVA 315–400 nm
UVB 280-315nm
UVC 100-280nm

UVA penetrates deep into tissues but is not as damaging as UVB because it has less photon energy than UVB.
UVB is considered the most dangerous to humans, although most of these rays are absorbed by the atmosphere.
UVCs are all absorbed by the atmosphere and do not reach the Earth's surface.

It has been established that the lens of the eye contains 0-beta-3-hydroxykynurenine, which absorbs UVA and thus protects the retina. When UV rays enter the eye, the main load falls on the cornea and lens, then the vitreous body and retina suffer.

The most dangerous UV for children under 10 years. Therefore, children need sunglasses more than adults.

There are three main quality standards for sunglasses:
- European standard (EN 1836:2005);
- Australian standard (AS/NZ 1067:2003);
- American standard (ANSI Z80.3-2001).

The European standard distinguishes 4 degrees of protection against UV:

• 0 - insufficient protection;
• 2 - sufficient protection;
• 6 - good protection;
• 7 - full protection.

The more UV absorption, the darker the lenses.

By and large, all three classifications are close - the gradation moves from a weak UV absorption to a stronger one. The difference is that at maximum UV protection, European standards allow an error of 5%, while US standards require almost 100% UV blocking.

European 6th and 7th degrees of protection correspond to Australian 3rd and 4th degrees, and are recommended for children depending on the brightness of the sunlight.

European 7th degree and Australian 4th degree are prohibited for use while driving a vehicle.

If sunglasses comply with European quality standards, there is a CE marking (Conformite Europeenne) on the temple or on the label. All goods sold in European countries have this marking. Glasses made in the USA are labeled 400UV or UV100%.

Sunglass lenses are made using special chemicals or coatings to effectively absorb UV rays.

Sunglass lenses are made from glass, plastic, and polycarbonate.

Lenses made of polycarbonate are considered optimal for children because they are impact-resistant and, therefore, safe. They have one drawback - they are easily damaged. Therefore, a special protective coating is applied to polycarbonate lenses (as a rule, these are sports glasses).

The quality of the lenses themselves is also extremely important for glasses. To determine this characteristic, there is a very simple method. Place the glasses at a comfortable distance from your face, cover one eye, and look through the center of the lens at an object that has straight lines (preferably in the shape of a rectangle) with the other. Slowly move the glasses up and down, from right to left. If there is no distortion of the lines, the lenses are of high quality.

It should be remembered that photochromic, polarized and mirrored lenses do not provide UV protection on their own and must also be labeled for UV protection.

An important point is the shape of the glasses. If bright sunlight enters the eyes over the top of the glasses or from the side, this will drastically reduce the effectiveness of the glasses themselves. Therefore, glasses should fit snugly on the nose, and the length of the temples should correspond to the shape of the child's face in order to ensure that the glasses fit the skin of the face as much as possible without causing discomfort. In this case, you should pay attention to the fact that the eyelashes do not rest against the glass.

For children with farsightedness, who are forced to wear glasses all the time, it is advisable to purchase glasses with a slight darkening of the lenses for the summer.

And now about the myths and misconceptions about sunglasses.

1. The darker the glass, the better the protection.

If the lenses in sunglasses are made of ordinary plastic, then the darker they are, the more dangerous for the eye. The darker the lens, the wider the pupils, the more UV penetrates into the eyes, the more negative the consequences. This is especially dangerous for children, so children under 10 years of age should either buy sunglasses that meet all sanitary requirements, or not buy any at all.

1. The higher the price, the better the quality.

Australian ophthalmologists, while examining the quality of sunglasses (from different countries and different brands), found that high cost does not guarantee high quality.

At the same time, protecting the eyes from the sun, one should not forget that light is extremely important for the development and full functioning of some brain structures.

Who would have thought that sunglasses, invented 200 years ago for the soldiers of Napoleon's army, will not lose their popularity to this day. Only with the development of technology, more and more demands are placed on glasses. They should not only be comfortable and fit the image, but also protect our eyes.

All models of glasses can be divided into three main groups: cosmetic (Cosmetic), which are a stylish accessory, but do not protect from sunlight, ordinary sunglasses (General), ideal for central Russia and models with a high degree of protection (High UV-protection), necessary for the highlands or the Arctic.

glasses material should be safe, light, and the lenses should not let in ultraviolet rays. Each material has its pros and cons. Plastic is safer than glass: such a lens will not shatter into a thousand pieces, but scratches easily appear on it. Glass lenses can be made with diopters, which is important for visually impaired people.

Glass color- Another decisive factor when choosing glasses. Now pink, orange or bright yellow color does not surprise anyone, but it is not always useful to look at life through rose-colored glasses: some shades can distort the colors of the surrounding world.

According to ophthalmologists, it is better to choose lenses of neutral colors that do not irritate the eyes and do not affect the retina.

Shades of gray or brown, dark green do not change the color scheme of surrounding objects, can lower intraocular pressure and calm the nervous system.

Blue color can cause the pupils to dilate, resulting in eye burns.

Pink, red, purple changes the perception of color and can lead to loss of orientation in space, nervousness, sleep disturbance.

Yellow color is suitable for cloudy weather, besides, it blocks blue. Besides enhancing contrast, yellow is good for driving or playing sports.

Black the color of the lenses is necessary only in the dazzling sun, for example, in the mountains or in the desert, and with prolonged wear, it can increase intraocular pressure.

Gradient effect lenses, which are darker at the top, are indispensable when you need to tone down a bright top color, for example, when driving a car or reading in the sun.

Photochromic glasses, also called chameleons, change color and light transmission depending on the lighting. These are high quality lenses that have varying degrees of tint.

There are also glasses with polarized lenses that belong to a special category. They, in addition to protecting against ultraviolet rays, neutralize 90% of glare on a wet road, snow or water.

Quality sunglasses must be certified where all the necessary information is provided. First of all, the ability to absorb ultraviolet rays. The UV-A symbol stands for type A ultraviolet, which is harmful to the retina and lens; this type of rays can accelerate the development of cataracts. The UV-B symbol indicates ultraviolet type B, which is not only dangerous for the cornea, but also impairs vision. The higher the UV-B value, the better. But the inscription “100% ultraviolet protection” on plastic glasses should alert you, because ultraviolet rays are 100% neutralized only by glass, and for plastic, an indicator of 80-90% is considered the norm.

Designation 400 nm indicates the maximum length of the beams from which this model is able to protect. If the indicator is less than 400, then this indicates that some of the rays will be transmitted, which can lead to conjunctivitis, a symptom of irritated eyes, corneal burns and provoke the development of cataracts.

When examining the temples of glasses, you can see the markings indicating the color of the lenses and the percentage of light that they absorb. For example, G-20 says that these are gray or green lenses (eng. gray - gray, green - green), which transmit 20% of the light and retain 80%, B-15 are brown lenses (brown - brown ), capable of transmitting 15% of the light and blocking 85%. For maximum eye protection, it is better to choose glasses with a lower number.

According to European standards, there are 5 degrees of protection from sunlight:

• Category 0- 80-100% of radiation is passed; glasses with such lenses can only be worn in cloudy weather, when the sun's rays rarely break through the clouds. TO
• Category 1- 43-80% of light is passed through. Glasses with such lenses are suitable for wearing in the dim sun.
• Category 2- passes 18-43% of the light. These glasses are indispensable on a sunny day.
• Category 3- from 8 to 18% of rays are passed through. When the summer sun is strong, sunglasses are a must.
• Category 4- passes 3-8% of the radiation. These are very dark lenses that provide protection from the harsh rays of the sun at ski resorts or seaside resorts.

Each manufacturer country has its own requirements for glasses. But sunglasses that meet the American standard ANSI Z80, British BS 2742 and German DIN 58217 are considered the best. Looking at the markings on the glasses and finding a discrepancy or rearrangement of letters and numbers, you can suspect a low-quality product. By the way, the brand name on the label and on the inside of the glasses must match.

Speaking of sunglasses, do not forget about the design. It is the glasses that can change the appearance beyond recognition. But in the latest collections there is no one fashion trend. A variety of colors, shapes, finishes and materials - this is the latest fashion for glasses. And the use of laser processing, riveting, rhinestones on frames or lenses only emphasizes the elegant style of modern models.

The truth about sunglasses

History of sunglasses
Even our distant ancestors noticed that bright sunlight is not only unpleasant, but also harmful to the eyes, because after a long stay in the sun, vision becomes worse. The first eye protection was created a long time ago. So, in the British Museum, an invention of the ancient Egyptians is kept, which is two thin saw cuts of an emerald connected by bronze plates (which resembles a modern frame). In the 16th century, sunglasses manufacturers added precious stones such as emerald, ruby, and sapphire to glasses because they enhanced the effect of protection from the sun's rays. Eskimo glasses are well known - bone shields with slots that limited the amount of light entering the eye.


Later, people began to use colored glass. The first industrial batch of sunglasses was produced 200 years ago in France for Napoleon's soldiers who participated in the African war. The lenses of the glasses were treated with soot and covered with a special varnish. In 1877, Josef Rodenstock opened a retail store for medical optics in Würzburg, where a small collection of sunglasses was also exhibited. In the 20th century, the fashion for sunglasses captured the whole world, and they became a commodity of mass consumption. However, in the new millennium, spectacle and lens manufacturers and spectacle vision professionals are beginning to pay more and more attention to the quality and functionality of sunglasses and lenses.
Modern requirements for glasses and lenses
Functionality
Even taking into account the fact that sunglasses are more often used by their owners as a fashion accessory or a means of expressing their own style, their main purpose is to protect the eyes from excessive sunlight. Quality eyeglasses protect against glare and protect the cornea, lens, and retina from the harmful effects of ultraviolet (UV) radiation and bright visible light. Factors such as comfort and image contrast play an important role in optimizing the performance of sunglasses and spectacle lenses.

Comfort
Spectacle frames are considered ergonomic when they do not interfere with the user: glasses do not put pressure on the nose and temples, they do not have to be constantly corrected on the face. When creating a frame, not only the shape of the rim opening and design are taken into account, but also the mandatory components of comfort.

UV protection
Although most of the sun's rays that reach the earth's surface are fairly harmless to humans, UV radiation can cause serious damage to the eyes at certain intensity and duration of exposure. The result can be clouding of the cornea and lens or damage to the retina. Short-wave blue light in the visible spectrum has also been reported to be harmful, so quality sunglasses offer complete protection against both hard UV radiation and short-wave radiation down to 400 nm.

Glare protection
Glare is eliminated to a greater or lesser extent by absorbing individual wavelengths of natural light, depending on the color and tint of the lens, as well as by applying high-quality anti-reflective coatings to the inner surface of the lenses. The fastest growing segment of the sun lens market is polarized lenses, which eliminate annoying plane polarized light reflected from shiny horizontal surfaces.

Increasing contrast
Under conditions of bright daylight against a blue sky, the solar spectrum contains a large proportion of short-wavelength visible radiation, which enhances light scattering. Blue color suppresses other colors, superimposed on them, and reduces the contrast of the perception of the image. Contrast-enhancing sun lenses cut out blue light to a large extent, resulting in a clearer visual experience.

Glasses and lenses for drivers
A very promising direction are sunglasses and corrective sun lenses for drivers. The use of sun lenses is determined by driving conditions - it can be bright sunlight or twilight, rain, fog (when there is a decrease in contrast), which is indicated in the documentation accompanying quality sunglasses.

Regulatory documentation and performance criteria
Currently, in our country and abroad, regulatory documents have been developed that regulate the light transmission of sun lenses according to filter categories and the rules for their use. In particular, in Russia it is GOST R 51831–2001 “Sunglasses. General technical requirements”, and in Europe - EN 1836: 2005 “Personal eye protection-Sunglasses for general use and filters for direct observation of the sun”.
Each type of sun lens is designed for specific lighting conditions and can be assigned to one of the filter categories. The filter identification is placed before the CE symbol. The table describes the characteristics of each filter category.

impact resistance
Although the main purpose of sunglasses is to protect against excessive UV and visible solar radiation, lenses must also protect the eyes from impact. Unlike everyday glasses, sunglasses are more likely to be worn outdoors, where they can be destroyed due to impact loads. Many manufacturers have created special materials for sun lenses to provide reliable eye protection from injury.

E-SPF
Studies have shown that not only direct UV light passing through the front surface of the lens is dangerous, but also reflected from its back surface into the eye. Dr. Karl Citek, professor of optometry at Pacific University in Oregon (USA), is one of the first researchers to link damage to the eye with exposure to reflected UV radiation from the inner surface of lenses. Studies have shown that up to 50% of all ultraviolet that enters the eyes enters them from the side and back, reflected from the back surface of the lenses. In collaboration with an independent laboratory, the E-SPF (Eye Sun Protection Factor) has been developed to provide an objective measure of the level of lens protection against harmful UV radiation. The calculation of the E-SPF factor takes into account the amount of this radiation reflected from the front and back surfaces of the lens, as well as the amount passing through the lens to the eye.

Colored lenses

One of the most popular ways of manufacturing sun lenses is dyeing. There are two main methods for the manufacture of tinted organic sunglass lenses: surface tinting and bulk tinting. Uniform and gradient surface tinting from dye solutions is the most common method for the production of lenses based on traditional plastics. This method is used both in large factories and in individual workshops. To obtain colored lenses from materials with a higher refractive index, it is necessary to color the hardening coatings. This production method is mainly used only in factories and optical laboratories. Surface staining is a simple and inexpensive method that allows you to get a wide variety of color shades of lenses. However, since the dye molecules in this case only penetrate the surface layer of the lenses (0.10–0.15 mm), the color may change over time. For example, under heavy use, gray lenses may take on a reddish or purple tint, as blue dye fades faster than red.

Many spectacle wearers choose the color of their sunglasses for aesthetic reasons, but they should be aware that color has a significant effect on the amount of light that reaches the eyes. Special compositions of dyes will allow the production of lenses that optimize the intensity and composition of the light flux absorbed and transmitted to the eye. For example, gray lenses evenly absorb all wavelengths of the visible spectrum, providing natural image contrast and color reproduction. Brown lenses filter out more light in the blue region of the spectrum, providing improved image contrast and depth perception. By informing your customers about the impact different colored lenses can have on their vision, you can help them find the glasses best suited to their activities and visual needs.

Photochromic lenses
Photochromic lenses change color intensity depending on the light. The main advantage of these lenses is their convenience: they provide the most comfortable light absorption for the eyes. Modern photochromic lenses are divided into two categories according to the initial light transmission. The first includes lenses that are colorless indoors and stain under the action of UV radiation. The second category consists of photochromic sun protection lenses with initial light absorption. It is possible that the buyer will prefer photochromic lenses for everyday glasses, and polarized, dark-colored from the surface will choose for sunglasses. Sun protection photochromic or evenly tinted lenses are recommended for a variety of outdoor activities.

Polarized lenses
Using the phenomenon of polarization has become a very popular method for adjusting the light transmission of lenses. Polarized lenses have been known for a long time, and today the benefits of these lenses have been appreciated not only by athletes - professionals and amateurs, but also by ordinary buyers, and due to a radical improvement in manufacturing technology and optical properties, prescription polarized lenses are becoming more widespread.

The basis of polarizing lenses is a polarizing filter film, which removes plane polarized light, the source of which is reflection from extended shiny surfaces - water, ice, snow, asphalt. In some situations, such as driving a car, reflected light can blind the driver, preventing them from seeing pedestrians or other vehicles in time. This light creates emergency situations and increases the response time to changing traffic conditions. Polarized lenses block out plane polarized (i.e., horizontally directed) light and improve a person's vision in difficult situations. Today, polarized lenses are found in the product range of many manufacturers and are becoming increasingly popular with spectacle wearers.
The smart choice of sunglasses
When buying sunglasses, it is best to immediately check whether they meet the requirements of the standards in terms of quality and safety of use. It is important to know that each pair of glasses must be accompanied by an instruction with the name of the manufacturer, with recommendations for the care of glasses, with the conditions for their use, as well as indicating the lens filter category in the range from 0 to 4. It should be noted that the higher category, the darker the lenses. Recall that category 4 always means that these glasses cannot be used while driving. Information about the category of sun lenses from leading manufacturers can be found on the original packaging of the lens, which must be attached to the finished glasses by the optician, or in the product catalog. Remember: complete and reliable information about the properties and use of sunglasses can only be obtained if they are purchased in an optical salon.

Sunglasses and etiquette

Have you ever thought about the etiquette of wearing sunglasses?

So here are some simple tips:
1. Sunglasses with very dark lenses should only be worn in very sunny weather or on holiday in the mountains. When it is cloudy outside, it is better to wear glasses with slightly tinted lenses.
2. When entering any room, be sure to take off your glasses.
3. Do not wear glasses on the top of your head - this is bad taste, which has recently become very common and fashionable. Remember that sunglasses are an accessory for the eyes, not for the hair, and cannot serve as a hoop.
4. If you want to ask someone something in the street, always take off your glasses. It is difficult for the interlocutor to carry on a conversation with you if your eyes are not visible. Taking off your sunglasses when talking on the street is a sign of a well-mannered person.
5. When meeting a person, it is also necessary to take off your glasses and do not immediately put them on after that, let people get used to you. During the meeting, your face should be completely open.

An exception to these rules can only be wearing sunglasses in places where UV protection is needed, such as at the beach. You can deviate from a few rules: talk to people or dine at a beach cafe in sunglasses, but in any case, you must take them off when meeting.
Be stylish and polite! Do not forget about the rules for choosing good glasses - fashionable and high-quality sunglasses will help not only improve your image, but also keep your eyes healthy for many years.

Healthcare. GOST R 51831-2001: Sun glasses. General technical requirements. OKS: Healthcare, Medical equipment. GOSTs. Sunglasses. General technical requirements. class=text>

GOST R 51831-2001

Sunglasses. General technical requirements

GOST R 51831-2001
Group P46

STATE STANDARD OF THE RUSSIAN FEDERATION

SUNGLASSES
General technical requirements
sun glasses. General technical requirements

OKS 11.040.70
OKP 94 4201

Introduction date 2003-01-01

Foreword

1 DEVELOPED by the State Unitary Enterprise "Center for Regulatory Information Systems" ("TKS-optics GOI") with the participation of the working group of the Technical Committee for Standardization TC 296 "Optics and optical devices"
INTRODUCED by the Main Directorate of Technical Policy in the Field of Standardization of the State Standard of Russia

2 ADOPTED AND INTRODUCED BY Decree of the State Standard of Russia dated November 30, 2001 N 499-st

3 This standard in parts 3.9-3.11, 4.2-4.4, 4.6 corresponds to the European standard EH 1836-97 "Personal eye protection. Sunglasses and general purpose filters"

4 INTRODUCED FOR THE FIRST TIME

1 area of ​​use

1 area of ​​use

This standard applies to glasses with filters of zero nominal optical power made of organic and inorganic materials, designed to protect against solar radiation, manufactured in the Russian Federation and imported from abroad, and establishes requirements for their physical (mechanical, optical and other) characteristics .
This standard does not apply to glasses intended for protection against solar radiation by a doctor's prescription, glasses used in industry, glasses with tinted filters, and ski goggles.
The requirements of this standard are mandatory.

2 Normative references

This standard uses references to the following standards:
GOST 8.332-78 State system for ensuring the uniformity of measurements. Light measurements. Values ​​of the relative spectral luminous efficiency of monochromatic radiation for daytime vision
GOST 7721-89 Light sources for color measurements. Types. Technical requirements. Marking
GOST 18491-90 Frames for corrective glasses. General technical requirements and test methods
GOST 26148-84 Photometry. Terms and Definitions
GOST R 51044-97 Spectacle lenses. General specifications

3 Definitions

The following terms and definitions apply in this standard:

3.1 sunglasses: Personal eye protection designed to reduce solar radiation affecting the eyes.

3.2 sunglass filter

3.3 photochromic filter sunglass filter whose transmittance in the visible region of the spectrum changes reversibly under the influence of ultraviolet radiation.

3.4 Clarified Photochromic Filter: A photochromic filter which, for a given sufficiently long period of time, has a maximum transmission.

3.5 darkened photochromic filter photochromic filter which, for a given sufficiently long period of time, has a minimum transmission.

3.6 gradient filter: A filter whose transmittance varies along some axis on the filter surface.

3.7 transmittance (spectral transmittance): According to GOST 26148.

3.8 relative spectral luminous efficiency of monochromatic radiation for daytime vision in this case, the wavelength is chosen so that the maximum value of this ratio is equal to one.
Note - The values ​​in the wavelength range from 380 to 780 nm correspond to those specified in GOST 8.332.

3.9 luminous transmittance

Where - relative spectral distribution of the radiation flux of a standard radiation source .
Notes

1 The values ​​of the spectral function of the product and for calculating the luminous transmittance are given in Table A.1 of Appendix A.

2 The values ​​of the relative spectral distribution of the radiation flux of a standard radiation source are set in GOST 7721.

3.10 transmittance in the ultraviolet region of the solar radiation spectrum

where is the spectral density of energy exposure in the ultraviolet region of the spectrum;
is the spectral efficiency of exposure to ultraviolet radiation on the human eye.
Note - The values ​​and are given in Table B.1 of Appendix B.

3.11 solar infrared transmittance

where nm, nm - the boundaries of the spectral range;
- distribution of the spectral density of energy exposure in the infrared region of the spectrum, W m.
NOTE Values ​​are given in Table B.1 of Annex B.

3.12 spectral efficiency of exposure to solar radiation

3.13 geometric center: The point on the surface of a sunglass filter that is the center of the circle in which the filter fits.

3.14 prismatic action deflection of a light beam as it passes through a given point on a sunglass filter from its original direction

3.15 photochromic filter transmittance
This International Standard specifies two different transmittance values ​​for a photochromic filter: and () is the transmittance of a photochromic filter in the clarified state at a temperature of 23 °C after the prescribed relaxation; , simulating the average conditions of outdoor exposure).

4 Technical requirements for sunglasses filters

4.1 Classification

4.1.1 Filters are classified according to the nature of solar radiation transmission:

a) evenly colored filters (in bulk);

b) gradient filters;

c) photochromic filters.

4.2 Transmission requirements for filters

4.2.1 Sunglass filters are classified into five categories based on the value of luminous transmittance .
The transmittance values ​​of sunglasses filters, depending on their categories, should correspond to those given in Table 1.

Table 1

4.2.1.1 Category "0" is set only for:
- photochromic filters in the clarified state;
- gradient filters with a transmittance in the geometric center of more than 80%;
- filters designed to protect against radiation in a specific area of ​​the solar spectrum, the luminous transmittance of which is more than 80%.

4.2.1.2 Mutual overlap of categories 0, 1, 2 and 3 is allowed in terms of transmittance values ​​not exceeding ±2%.

4.2.1.3 When determining the luminous transmittance and category of gradient filters, use the value at the geometric center.

4.3 General requirements for transmittance

4.3.1 Uniformity of luminous transmittance over the surface of a spectacle glass

4.3.1.1 The difference in luminous transmittance between any two points of the filter inside a circle with a diameter of 40 mm centered at the geometric center (except for the edge zone of 5 mm) should be no more than 10% of the larger value limiting for this category; for category 4 filters - no more than 20%.

4.3.1.2 For gradient filters, the uniformity requirement shall be met along a line perpendicular to the direction of the transmission gradient.

4.3.1.3 For spectacle frame filters, the uniformity requirement shall be met along a line parallel to the line connecting the geometric centers of the spectacle frame openings.

4.3.1.4 For filters in a spectacle frame, the difference between the luminous transmittances at the geometric centers of the right and left filters must not exceed 10% of the highest transmittance value.

4.3.2 Special requirements for transmission of certain types of filters

4.3.2.1 The category of a photochromic filter is determined by the value of the transmittance in the clarified state and in the darkened state after 15 minutes of exposure to solar radiation or its simulator.
For both states, the requirements given in 4.2 and 4.3 shall be met.
The ratio for photochromic filters must be at least 1.25.

4.4 Requirements for optical power and prismatic action of filters

4.4.1 Depending on the accuracy of manufacture and indicators of appearance, the filters are divided into groups I and II.

4.4.2 Deviations from zero optical power and prismatic effect of filters of groups I and II should not exceed the values ​​specified in Table 2.

table 2

4.5 Performance and material requirements

4.5.1 The characteristics of sunglasses filters must comply with the requirements of GOST R 51044.

4.5.2 Requirements for the material of sunglasses filters - according to GOST R 51044.

4.6 Transmittance stability requirements

4.6.1 The difference in luminous transmittances after exposure for 100 hours to radiation simulating the average conditions of outdoor illumination should be no more than:
±5% - for filters of category 0;
±10% - for category 1 filters;
±20% - for filters of other categories.

5 Requirements for finished sunglasses

5.1 Design requirements

5.1.1 Sunglass frames must be free of protrusions, sharp corners, and other defects that cause discomfort or injury when used as intended.

5.1.2 Frames for sunglasses must be manufactured in accordance with the requirements of GOST 18491.

5.2 Material requirements

5.2.1 Sunglasses (frames, sunglasses filters) must be made of materials that have passed toxicological tests in the prescribed manner and have a hygiene certificate.

6 Marking

6.1 Sunglasses must be marked on the frame, packaging or label.
It is allowed to apply marking in any combination, for example, on a frame and a label.

6.2 The marking must contain the following information:
- name of the manufacturer (or trademark);
- sunglass filter category according to table 1;
- Sunglasses filter type.

6.3 Sunglass filters that are not fitted into a frame must be marked on their packaging or label with:
- name and address of the manufacturer or supplier;
- sunglass filter category;
- instructions for storage, care and cleaning;
- sunglass filter group (I or II).

6.4 Additional information provided by the manufacturer or supplier of sunglasses on the label should contain the following data:
- clarification of the marking;
- position of the geometric center;
- nominal value of light transmittance .

APPENDIX A (informative). Spectral functions for calculating luminous transmittance

APPENDIX A
(reference)

Table A.1

______________
* The value for the wavelength of 590 nm is given in accordance with the original. - Note.

APPENDIX B (informative). Spectral functions for calculating the transmittance in the ultraviolet region of the spectrum

APPENDIX B
(reference)

Table B.1

APPENDIX B (informative). Spectral functions for calculating the transmittance in the infrared region of the spectrum

APPENDIX B
(reference)

Table B.1

In summer, the purchase of sunglasses becomes absolutely necessary, although it is necessary to protect the eyes and especially the delicate skin around them from excess ultraviolet radiation at any time of the year. What is required of good glasses? They should be comfortable, fashionable, look great and provide a high level of protection. A stylish and fashionable element and at the same time a means of protecting the eyes from ultraviolet radiation - the requirements for sunglasses are quite high. How to choose exactly what you need?

To choose good sunglasses, you first need to decide whether they will be made of glass or plastic. Glass lenses perfectly protect against ultraviolet rays, almost do not distort objects, and scratches appear on them much less frequently. The disadvantages of such glasses include fragility: the glass breaks easily, while it is possible that the fragments will damage the eyes. Glass glasses are heavier than plastic and can fog up. If a child needs glasses, the option with glass lenses is not even considered.
Plastic lenses are safe and weigh less. However, ordinary plastic easily transmits ultraviolet light, and glasses made of it do not provide any protection. In order for plastic glasses to be effective, the material must contain special additives and coatings: anti-reflective, photoprotective, photochromic, water-repellent. So when buying glasses made of plastic, you need to be sure of their high quality. This is possible if you give preference to branded glasses and purchase them in trustworthy stores. Sunglass labels usually list the wavelengths that the lenses block. In good glasses, this figure will be at least four hundred nm (nanometers). If this indicator does not reach the desired figure, then the lenses will pass near ultraviolet. It is also worth paying attention to the refractive index. The higher it is, the thinner and more transparent the lens.

A very important factor is the color of the lenses. Although the assortment of glasses is striking in variety, not all of them can be worn without harm to the eyes and health in general. The ideal color for "glasses" is dark green or dark gray. The first one filters out ultraviolet radiation as much as possible, and gray glasses do not disturb color perception.

But rose-colored glasses fully justify their bad reputation: wearing them affects the psyche. Glasses of any shades of red should not be worn at all: they distort all colors, which can lead to a loss of orientation in space. Glasses with blue or purple lenses are also not good for constant wear - they adversely affect vision. Drivers should choose brown glasses, and in case of poor visibility, special yellow ones will help. If you are planning a trip to the mountains, to the water, or any other place where the sun is especially bright, you can buy heavily tinted glasses with a mirror finish. But glasses with transitions from a dark top to a light bottom are an unsuccessful purchase: the eyes in them will quickly get tired.

However, it's time to remember that glasses are not only eye protection, but also a fashion accessory. To choose the right sunglasses, you need to pay special attention to the color and shape of the frame. The color of the frame should be chosen depending on the shade of the hair. For blondes, stylists recommend dark-colored frames - black, blue or green. Exotic colors are also suitable for them - leopard or under the skin of reptiles. And for brunettes, light frames will be good, as well as all metallic shades up to golden and silver. Red-haired girls will be irresistible in frames of pastel colors: light green, lilac, blue. If we are talking about men's glasses, the combination of dark hair - light frame and vice versa will be correct.

When choosing a frame, you need to take into account the shape of the face - after all, well-chosen glasses should add attractiveness and certainly not spoil anything. On this occasion, stylists also have recommendations. Owners of regular features and an oval face will suit almost any frame. So it is easiest for them to choose the shape of sunglasses.

To give a more regular shape to a square face, you need to visually reduce the width of the cheekbones, and make the chin longer. In this case, it is better to buy glasses that are located high on the bridge of the nose. A thin metal frame and a shape that is slightly rounded at the bottom will also help to achieve the desired effect. If the face is triangular, it is better, on the contrary, to choose glasses that sit low on the bridge of the nose. Let the shape of the lenses be oval and the frame thin. Rectangular dark glasses are suitable for a round face - they will make the face visually narrower. Black or dark brown glasses with a fairly wide bridge will add harmony to a rectangular face.

When making this purchase, it is also important not to get instead of good branded glasses - a fake, with which, to be honest, the market is literally flooded. How to choose sunglasses in such conditions and not make a mistake? The easiest and most affordable quality test is to make sure that the glasses do not distort the image. To check this, you can put glasses on a piece of fabric with a square weave. The lower the distortion, the better the lenses in front of you.

Carefully inspect the frame - how carefully it is made, slightly bend the temples of the glasses, adjusting them to your size. A high-quality frame should be elastic, it should be equally easy to take on new shapes and return to the old ones.

If you buy branded glasses, look for the manufacturer's information not only on the label, but also on the inside of the temple, as well as in the corner of the lens. And, of course, you need to make sure that the new frame does not press on the bridge of the nose, and the temples do not pinch: this accessory should be very comfortable - after all, you will have to wear it almost constantly in the summer.