Sunglasses. General technical requirements. Sun protection lenses Functions of eye protection

There are European, American, Australian requirements for the quality of sunglasses (over-the-counter).

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:

• 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 280–315 nm
UVC 100–280 nm

UVA penetrates deep into tissue but is not as destructive as UVB because it has less photon energy than UVB.
UVB is considered the most dangerous for humans, although the bulk 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 thereby protects the retina. When UV rays enter the eyes, the main load falls on the cornea and lens, then the vitreous body and retina suffer.

UV is most dangerous for children under 10 years of age. 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 levels of UV protection:

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

The greater the UV absorption, the darker the lenses.

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

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

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

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

To obtain effective absorption of UV rays, special chemicals are used or a special coating is applied to them when making lenses for sunglasses.

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, polycarbonate lenses (usually sports glasses) are coated with a special protective coating.

The quality of the lenses themselves is also extremely important for glasses. There is a very simple method to determine this characteristic. Place your glasses at a comfortable distance from your face, cover one eye, and look through the center of the lens with the other at an object with straight lines (preferably in the shape of a rectangle). 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 mirror lenses do not protect against UV on their own and must also be labeled with the degree of UV protection.

An important point is the shape of the glasses. If bright sunlight hits your eyes from above or from the side, it will dramatically reduce the effectiveness of the glasses themselves. Therefore, the glasses should fit tightly on the nose, and the length of the temples should match the shape of the child’s face to ensure maximum fit of the glasses to the skin of the face without causing discomfort. In this case, you should pay attention to ensure 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 slightly darkened lenses for the summer.

And now about the myths and misconceptions regarding 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 they are for the eyes. 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 should either buy sunglasses that meet all health requirements or not buy any at all.

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

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

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

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

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

Material for making glasses should be safe, lightweight, and the lenses should not transmit 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 appear on it easily. 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 colors won’t surprise anyone, but it’s not always useful to look at life through rose-colored glasses: some shades can distort the colors of the world around us.

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.

The blue color can cause dilation of the pupils, which can result in eye burns.

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

Yellow is suitable for cloudy weather and also blocks blue. Additionally, by enhancing contrast, yellow is a good color for driving or playing sports.

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

Lenses with gradient effect, more darkened at the top, are indispensable when you need to mute the 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 darkness.

There are also glasses with polarized lenses, which belong to a special category. In addition to protecting against ultraviolet rays, they neutralize glare on a wet road, snow or water by 90%.

High-quality sunglasses must have a certificate, where all the necessary information is indicated. First of all, the ability to absorb ultraviolet rays. The UV-A icon means ultraviolet type A, which is dangerous to the retina and lens; this type of rays can speed up the development of cataracts. The UV-B icon denotes type B ultraviolet light, 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, 80-90% is considered the norm.

Designation 400 nm indicates the maximum length of rays that this model can protect against. If the indicator is less than 400, then this indicates that some of the rays will be missed, which can lead to conjunctivitis, a symptom of irritated eyes, a burn of the cornea and provoke the development of cataracts.

By examining the temples of your glasses, you can see markings indicating the color of the lenses and the percentage of light they absorb. For example, G-20 says that these are gray or green lenses (English gray - gray, green - green), which transmit 20% of light and retain 80%, B-15 - these are brown lenses (brown - brown ), capable of transmitting 15% of 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 transmitted; 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 transmitted. Glasses with such lenses are suitable for wearing in dim sun.
• Category 2- 18-43% of light passes through. These glasses are indispensable on a sunny day.
• Category 3- from 8 to 18% of rays are transmitted. When the summer sun is active, sunglasses are necessary.
• Category 4- 3-8% of radiation passes through. These are very dark lenses that provide protection from aggressive sun rays at ski or sea resorts.

Each manufacturing country has its own requirements for glasses. But the best sunglasses are those that comply with the American standard ANSI Z80, the British BS 2742 and the German DIN 58217. 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 temple of the glasses must match.

When talking about sunglasses, don't forget about design. It is glasses that can change your appearance beyond recognition. But there is no single fashion trend in the latest collections. A variety of colors, shapes, finishes and materials - this is the latest fashion in glasses. And the use of laser processing, rivets, rhinestones on frames or lenses only emphasizes the elegant style of modern models.

The whole truth about sunglasses

History of sunglasses
Even our distant ancestors noticed that bright sunlight is not only unpleasant, but also harmful to the eyes, since after a long stay in the sun, vision becomes worse. The first eye protection products were created quite a long time ago. Thus, the British Museum houses an invention of the ancient Egyptians, which consists of two thin cuts of emerald connected by bronze plates (which resembles a modern frame). In the 16th century, sunglasses manufacturers added precious stones - emerald, ruby ​​and sapphire - to glass because they enhanced the effect of protection from the sun's rays. Eskimo glasses are well known - bone shields with slits 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 glasses' glasses were treated with soot and coated with a special varnish. In 1877, in Würzburg, Joseph Rodenstock opened a retail store selling medical optics, where a small collection of sunglasses was also exhibited. In the 20th century, the fashion for sunglasses took over the whole world, and they became a consumer product. However, in the new millennium, manufacturers of glasses and lenses, professionals in the field of spectacle vision correction are beginning to pay increasing 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 remains to protect the eyes from excess sunlight. Quality glasses prevent 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 increased image contrast play an important role in optimizing the functional properties of sunglasses and spectacle lenses.

Comfort
Spectacle frames are considered ergonomic when they do not interfere with the user: the glasses do not put pressure on the nose and temples, and they do not have to be constantly adjusted on the face. When creating a frame, not only the shape of the rim opening and design are taken into account, but also the essential 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 a certain intensity and duration of exposure. The result may be clouding of the cornea and lens or damage to the retina. There is evidence of the adverse effects of short-wave blue radiation in the visible spectrum, so quality sunglasses provide complete protection from hard UV radiation and from short-wave radiation up to 400 nm.

Anti-glare
Elimination of glare is carried out to a greater or lesser extent by the absorption of individual wavelengths of natural light, depending on the color and darkening coefficient 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.

Increase contrast
In bright daylight conditions against a blue sky, the solar spectrum contains a high proportion of short-wavelength visible radiation, which enhances light scattering. Blue color suppresses other colors by overlapping them and reduces the contrast of the perceived image. Contrast-enhancing sun protection lenses cut out blue light to a large extent, providing a clearer visual experience.

Glasses and lenses for drivers
A very promising area is 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), about which there is relevant information in the documentation accompanying high-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 this 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 classified into 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 radiation from the sun, the lenses must also provide adequate protection from impacts. Unlike everyday glasses, sunglasses are more likely to be worn outdoors, where they can be subject to damage due to impact loads. Many manufacturers have created special materials for sun lenses to provide reliable eye protection from injury.

E-SPF factor
Studies have shown that not only direct UV light passing through the front surface of the lenses 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 eye damage to exposure to reflected UV radiation from the inside of lenses. Studies have shown that up to 50% of all ultraviolet light that enters the eyes enters them from the sides and behind, reflecting from the back surface of the lenses. In collaboration with an independent laboratory, the E-SPF (Eye Sun Protection Factor) was developed, which guarantees an objective measurement of the level of protection of lenses from harmful UV rays. 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 that passes through the lens to the eye.

Painted lenses

One of the most popular methods for producing sun lenses is dyeing. There are two main methods for producing colored sun-protection organic lenses: surface dyeing and bulk dyeing. Uniform and gradient surface dyeing from dye solutions is the most common method for producing 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 paint reinforcing coatings. This production method is mainly used only in factories and optical laboratories. Surface tinting is a simple and inexpensive method that allows you to obtain a wide variety of lens colors. However, since the dye molecules in this case penetrate only into the surface layer of the lenses (0.10–0.15 mm), the color may change over time. For example, during intensive use, gray lenses may acquire a reddish or purple tint, since the blue dye fades faster than the red dye.

Many eyeglass wearers choose the color of their sun lenses for aesthetic reasons, but they should keep in mind that the color significantly affects the characteristics of the light output reaching the eyes. Special compositions of dyes will make it possible to produce 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 rendition. Brown lenses filter out more light in the blue region of the spectrum, providing improved image contrast and depth perception. By educating your clients about the impact different lens colors can have on their vision, you can help them choose the glasses that best suit their activities and vision needs.

Photochromic lenses
Photochromic lenses change color intensity depending on the light level. 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 based on their initial light transmission. The first includes lenses that are colorless indoors and become colored under the influence of UV radiation. The second category consists of photochromic sun protection lenses with initial light absorption. It is quite possible that the buyer will prefer photochromic lenses for everyday glasses, and will choose polarized, dark-colored lenses for sunglasses. Sun protection photochromic or evenly tinted lenses are recommended for a variety of outdoor activities.

Polarized lenses
The use of polarization has become a very popular method for regulating the light transmission of lenses. Polarized lenses have been known for quite a long time, and today the benefits of these lenses are appreciated not only by professional and amateur athletes, but also by ordinary buyers, and thanks to the radical improvement in manufacturing technology and optical properties, prescription polarized lenses are becoming increasingly widespread.

The basis of polarized 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 when driving a car, the reflected light blinds the driver, preventing him from seeing pedestrians or other vehicles in time. This light creates emergency situations and increases response time to changing road conditions. Polarized lenses block plane-polarized (i.e., horizontally directed) light and improve the quality of a person's vision in difficult situations. Today, polarized lenses are present in the product range of many manufacturers and are becoming increasingly popular among glasses wearers.
The smart choice of sunglasses
When purchasing 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 instructions with the name of the manufacturer, recommendations for the care of the glasses, the conditions for their use, as well as an indication of the lens filter category in the range from 0 to 4. It should be noted that the higher category, the darker the lenses. Let us remind you that category 4 always means that these glasses cannot be used when driving a car. Information about the category of sun lenses from leading manufacturers can be found on the original lens packaging, which should be included with the finished glasses by the optician, or in the product catalogue. Remember: complete and reliable information about the properties and use of sunglasses can only be obtained if you purchase them at an optical salon.

Sunglasses and etiquette

Have you ever wondered 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 vacation 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 top of your head - this is bad taste, which has recently become very common and fashionable. Don't forget that sunglasses are an accessory for the eyes, not for the hair, and cannot serve as a headband.
4. Eating on the street If you want to ask someone something, always take off your glasses. It is difficult for your interlocutor to have 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 you should not put them on immediately after that, let people get used to you. During introductions, your face should be completely open.

The only exception to these rules would be wearing sunglasses in places where UV protection is needed, such as on the beach. You can deviate from a few rules: talk with people or have lunch at a beach cafe while wearing sunglasses, but in any case, you must take them off when meeting people.
Be stylish and polite! Don’t forget about the rules for choosing good glasses - fashionable and high-quality sunglasses will help not only improve your image, but also maintain eye health for many years.

Healthcare. GOST R 51831-2001: Sunglasses. General technical requirements. OKS: Healthcare, Medical equipment. GOST standards. 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

Date of introduction 2003-01-01

Preface

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

2 ADOPTED AND ENTERED INTO EFFECT by Resolution of the State Standard of Russia of 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, intended for protection from solar radiation, produced on the territory of the Russian Federation and imported from abroad, and establishes requirements for their physical (mechanical, optical and other) characteristics .
The standard does not apply to glasses intended for protection from solar radiation as prescribed by a doctor, to glasses used in industry, to glasses with tinted filters, or to ski masks.
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 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 technical conditions

3 Definitions

The following terms and definitions apply to this standard:

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

3.2 sunglass filter: Optical element of personal eye protection that allows vision.

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

3.4 photochromic filter in cleared state: A photochromic filter that has maximum transmittance over a given sufficiently long period of time.

3.5 photochromic filter in dark state: A photochromic filter that has minimal transmission for a given sufficiently long period of time.

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

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

3.8 relative spectral luminous efficiency of monochromatic radiation for daytime vision: The ratio of two radiation fluxes with wavelengths and causing visual sensations of equal strength under precisely defined photometric conditions; in this case, the wavelength is chosen in such a way that the maximum value of this ratio is equal to unity.
Note - Values ​​in the wavelength range from 380 to 780 nm correspond to those established in GOST 8.332.

3.9 luminous transmittance: Value determined by the formula

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

1 The values ​​of the spectral function of the product and for calculating the light 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 established in GOST 7721.

3.10 transmittance in the ultraviolet region of the solar radiation spectrum: The value in sections of the spectral range from 280 to 315 nm (UV-B) and from 315 to 380 nm (UV-A) for and is calculated accordingly using the formulas

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

3.11 transmittance in the infrared region of the solar radiation spectrum: Value determined by the formula

where nm, nm are the boundaries of the spectral range;
- distribution of spectral density of energy irradiation in the infrared region of the spectrum, W m.
Note - The values ​​are given in Table B.1 of Annex B.

3.12 spectral efficiency of exposure to solar radiation: A function characterizing the dependence on the wavelength of exposure to solar radiation on the eye.

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

3.14 prismatic action: The deflection of a light beam when passing through a given point on a sunglasses filter from its original direction.

3.15 photochromic filter transmittance: A value that depends, within certain limits, on the energy of ultraviolet radiation passing through the filter and temperature.
This standard specifies two different transmittance values ​​for a photochromic filter: and ( - the transmittance of a photochromic filter in the cleared state at a temperature of 23 °C after the specified relaxation; - the transmittance of the photochromic filter in a darkened state at a temperature of 23 °C after 15 minutes of exposure to radiation , simulating average conditions of external irradiation).

4 Technical requirements for sunglasses filters

4.1 Classification

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

a) uniformly colored filters (in bulk);

b) gradient filters;

c) photochromic filters.

4.2 Filter transmission requirements

4.2.1 Sunglasses filters are divided into five categories based on their luminous transmittance value.
The transmittance values ​​of sunglasses filters, depending on their categories, must correspond to those given in Table 1.

Table 1

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

4.2.1.2 Mutual overlap of categories 0, 1, 2 and 3 is allowed for transmittance values ​​of no more than ±2%.

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

4.3 General requirements for transmittance

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

4.3.1.1 The difference in light transmittance between any two filter points 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 homogeneity requirement must be satisfied along a line perpendicular to the direction of the transmission gradient.

4.3.1.3 For filters in spectacle frames, the uniformity requirement must 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 spectacle frames, the difference in light transmittance at the geometric centers of the right and left filters should be no more than 10% of the largest transmittance value.

4.3.2 Special requirements for the transmission of certain types of filters

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

4.4 Requirements for optical power and prismatic effect of filters

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

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

table 2

4.5 Requirements for characteristics and materials

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 Requirements for transmittance stability

4.6.1 The difference in light transmittance after exposure for 100 hours to radiation simulating average outdoor lighting conditions 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 ready-made sunglasses

5.1 Design requirements

5.1.1 Sunglasses frames must not have protrusions, sharp corners or other defects that lead to discomfort or injury when used for their intended purpose.

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

5.2 Material requirements

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

6 Marking

6.1 Sunglasses must be marked, which must be placed on the frame, packaging or label.
Marking can be applied in any combination, for example, on the frame and label.

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

6.3 Sunglasses filters that are not inserted into the frame must have a marking on the packaging or label containing:
- name and address of the manufacturer or supplier;
- sunglasses filter category;
- instructions for storage, care and cleaning;
- sunglasses filter group (I or II).

6.4 Additional information provided by the manufacturer or supplier of sunglasses on the label must contain the following data:
- explanation of markings;
- position of the geometric center;
- nominal value of luminous transmittance.

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

APPENDIX A
(informative)

Table A.1

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

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

APPENDIX B
(informative)

Table B.1

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

APPENDIX B
(informative)

Table B.1

In the summer, buying sunglasses becomes absolutely necessary, although you need to protect your eyes and especially the delicate skin around them from excess ultraviolet radiation at any time of the year. What do you need from 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 provide excellent protection from 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, and there is a possibility that the fragments will damage the eyes. Glass glasses are heavier than plastic glasses and can also 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 radiation, and glasses made from it do not provide any protection. In order for plastic glasses to be effective, the material must contain special additives and coatings: anti-glare, 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 from trustworthy stores. Sunglasses labels usually indicate the wavelengths that the lenses block. With good glasses, this figure will be no lower than four hundred nm (nanometers). If this indicator does not reach the required figure, then the lenses will transmit near ultraviolet radiation. 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 range of glasses is amazingly diverse, not all of them can be worn without harm to the eyes and health in general. The ideal color for “glass” is dark green or dark gray. The first filters out ultraviolet radiation as much as possible, and gray glass does not interfere with color perception.

But rose-colored glasses fully justify their bad reputation: wearing them affects the psyche. Glass of any shade of red should not be worn at all: they distort all colors, which can lead to loss of orientation in space. Glasses with blue or violet lenses are also not good for constant wear - they have a detrimental effect on 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 coating. But glasses with transitions from dark top to light bottom are a bad purchase: your eyes will get tired quickly in them.

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 your hair. For blondes, stylists recommend dark-colored frames - black, blue or green. Exotic colors are also suitable for them - leopard print or reptile skin. And for brunettes, light frames will be good, as well as all metallic shades, including gold 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 correct combination would be dark hair - light frames and vice versa.

When choosing frames, you need to take into account the shape of your face - after all, well-chosen glasses should add attractiveness and certainly not spoil anything. Stylists also have recommendations on this matter. For those with regular features and an oval face, almost any frame will suit you. 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 your cheekbones and make your 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 slightly rounded at the bottom will also help achieve the desired effect. If your face is triangular in shape, it is better to choose glasses that sit low on the bridge of your nose. Let the lens shape be oval and the frame thin. Rectangular sunglasses will suit 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 fake glasses instead of good branded ones, with which, to be honest, the market is literally flooded. How to choose sunglasses in such conditions and not make a mistake? The simplest and most accessible quality test is to make sure that the glasses do not distort the image. To test this, you can place the glasses on a piece of square-weave fabric. The less distortion there is, the better the quality of the lenses you have.

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, equally easy to take on new shapes and return to the previous ones.

If you are buying branded glasses, look for manufacturer 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 put pressure on the bridge of your nose, and that the temples do not pinch: this accessory should be very comfortable - after all, you will have to wear it almost constantly in the summer.