How to choose sunglasses?

The most valuable thing is cherished like the apple of an eye. This catchphrase is associated with the happy opportunity of a healthy person to perceive the world around him in the fullness of colors and images. Nature has taken care to protect our eyes from excessively bright light and other negative influences: the iris regulates the intensity of the light flux entering the eye; the muscles of the eyelids contract instinctively if the light is too bright; The lacrimal glands secrete a fluid that moisturizes the outer layer of the eyeball and cleans it of dust. However, this is not enough to completely avoid the harmful effects of ultraviolet radiation on the organs of vision. Sunglasses

Sunglasses are designed to protect the eyes from the harmful effects of ultraviolet radiation. or chronic pathologies that lead to decreased vision. Lenses in such glasses function as light filters that block ultraviolet rays of dangerous for the eyes spectra with wavelengths of 280-320 nm and 320-400 nm, which have the symbols UV-A and UV-B.

Let's define what types of sunglasses are.

Types of sunglasses

Types of sunglasses are distinguished by their function, the type of material from which the lenses are made, color, coating and the method of attaching the spectacle glass...

By function, sunglasses can be designed to improve vision, for sports, for work in special conditions and simply for protection from ultraviolet radiation.

1. Sunglasses for improving vision

A)To improve vision, usestenopic glasseswith solid black lenses, in which holes of a standard diameter are made that transmit light waves of a certain length. Such glasses relieve tension in the eye muscles and are able to correct vision in case of progressive myopia. They are put on for 15-20 minutes, during which one has to look at objects through holes of 1 mm. In this case, synchronous muscular work occurs, aimed at focusing the gaze on any object. Ophthalmologists consider such gymnastics for the eyes to be useful for the prevention of certain diseases that cause visual impairment in adolescence and adulthood. Suitable for work in urban environments with dim autumn and spring sun.

  • Category 2 - sunglasses with an average degree of protection and a level of light transmission corresponding to 18 - 43%. These glasses are used by drivers, rescuers, and the military who work in the climatic zone of the middle zone.
  • Category 3 - strong sunglasses that transmit 8-18% of the light. They are used to protect from the bright daytime sun, if the work is associated with even a short stay in unshaded places. Long distance drivers, sailors and mine rescuers prefer glasses with dark polarizing lenses, mirrors or gradient dusting.
  • Category 4 - the strongest sunglasses with a light transmission of 3-8%. You cannot do without them if you have to work in blinding snow, deserts, tropics or areas with increased solar activity. The equipment of polar explorers and climbers includes sunglasses of a special design: with round dark lenses and a leather retainer that does not let light through the frame.
  • When choosing glasses for work, you should carefully study their quality certificate, which indicates the degree of protection and contains the characteristics of the materials used for the manufacture of lenses, frames and light protection filters.

    Pros

    Sunglasses for work in special conditions are produced taking into account their purpose. The quality of the lenses, their color and shape in glasses of this type strictly correspond to the geometric pattern of the frame, which is designed in such a way that direct or reflected sunlight cannot reach the retina. Lenses are made from high quality lightweight polymeric materials, using eye-friendly formulations with antistatic and photochromic properties for coating and darkening.

    Cons

    Glasses of this type do not use glass lenses: they can break at the most inopportune moment. Tinted polymer lenses require careful handling, as scratches and other damage remain on their surface layer, due to which the quality of visibility is sharply reduced. The cost of sunglasses depends on the model, but always remains high: the most powerful glasses for working in Arctic conditions are more expensive, glasses of 1 and 2 protection categories are slightly cheaper.

    4. Sunglasses for leisure

    If sunglasses are needed for normal use, in their range you can choose exactly the option that, in terms of quality, style, shape and degree of protection, fully satisfies the aesthetic need the future owner and will provide comfort for his vision.

    The most popular of modern sunglasses are models withdrop-shapedlenses in a thin metal frame, created by Ray Ban at the beginning of the 20th century, but have not lost their relevance to this day. In 1952, the collection of this company was complemented by trapezoidal horn-rimmed glasses. CalledWayfarers, they are among the top five most sought-after products in this spectrum of the consumer market.

    Later appearedtishades- glasses with small round glass lenses of different colors in a weightless frame. Modern stylists consider their form to be classic, although the degree of protection from ultraviolet rays in this model is not high enough.

    The extravagance of youth modelstight-fitting, orpanoramicglasses ceased to irritate adherents of classical forms, when it turned out that they provide maximum eye protection and are very comfortable for winter sports sports.Panoramicglasses consist of one colored lens curved in a semicircle, completely covering the eyes and the upper part of the face.

    Panoramic sunglasses

    The shape of the frame is a matter of taste, but the color of the lenses and the material from which they are made largely determines the state of vision, therefore, when choosing glasses, you should be aware of some of the features of optical filtering of sunlight used in the development of models of sunglasses.

    • Black lenses are considered neutral: they do not distort colors, although they dim their brightness.
    • Gray and green lenses retain their color, calm the nervous system, but do not interfere with the penetration of the blue and violet spectrum rays.
    • Brown, yellow and orange lenses enhance contrast and clarity, but distort colors.
    • Golden yellow and amber lenses block blue and are considered the best UV filters.
    • Pink and purple lenses provide little or no eye protection. They, along with jewelry, are classified as decorative additions.
    • Photochromic lenses, which change color depending on the light, are easy to use and do not cause eye fatigue on sunny days.
    • Graduated, semi-tinted lenses provide protection from too bright sun, enhance contrast and maintain natural colors when looking down, such as when reading or working with the dashboard.

    Lenses can be made of quartz glass, polycarbonate, or other types of plastics. Glasses with tinted glass lenses are UV-resistant, but heavy and easy to break. Plastic lenses are best for sunglasses - it is only important that their quality meets the required standards.

    Pros

    Sunglasses designed for general use are presented in a wide range of models, among which everyone can choose the best option for work and play. A variety of color combinations of frames and glass or plastic lenses with different degrees of protection allows you to purchase glasses with filtration of ultraviolet and infrared radiation, suitable for amateur sports, driving a car, long stay on sea beaches and just feeling comfortable while walking.

    Disadvantages

    Certain colors of lenses, when constantly wearing sunglasses, have a negative effect on the state of the nervous system and visual organs. According to the observations of ophthalmologists, yellow and orange filters cause an increase in intraocular pressure, and lenses of the blue-violet range have a detrimental effect on the state of the lens. In addition, cheap glasses offer little or no protection from UV rays. Instead of expensive anti-reflective and photochromic spraying, dimmers of dubious quality are applied to the outer surface of lenses in fake glasses, and this leads to the development of complex eye diseases and decreased vision.

    Types of sunglassesProsConsApplication
    1. Sunglasses to improve vision:

    - stenopic glasses

    Do not distort colors; increase the sharpness;

    reduce eye strain;

    are used for therapeutic and prophylactic purposes.

    Decrease contrast;

    do not protect against UV radiation.

    Recommended to alternate with regular sunglasses when worn.
    - sunglasses with dioptersProtect eyes from the bright sun;

    do not limit the field of view;

    have a degree of protection from 20 to 85%;

    reflect UV rays.

    Difficulty of selection;

    limited functionality.

    Some types of sunglasses can be replaced.
    2. Sports SunglassesProtect against UV rays;

    protect the organs of vision from dust and unwanted irritants;

    improve contrast perception;

    have a wide color spectrum of lens coloration;

    warn "snow blindness";

    reduce the intensity of ultraviolet glare.

    Limited choice of prescription lenses.Sports sunglasses are designed to provide eye protection for a specific sport. The models should be used as intended.
    3. Sunglasses for special conditionsCompletely protect eyes from direct and reflected sunlight;

    are of high quality.

    Exposure of the outer layer of lenses to mechanical stress.Each type of glasses is designed for specific conditions of work.
    4. Sunglasses for relaxation.Wide range of models;

    different degrees of protection;

    filtering ultraviolet and infrared radiation;

    multifunctionality.

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    Negative effect of orange and blue colored lenses;

    the possibility of counterfeiting.

    The choice should be consistent with the acquisition goal of UV protection.

    Other useful tips for choosing sunglasses

    1. When choosing sunglasses, you must follow the purpose for which they are needed. Cosmetic glasses cannot be used as sports glasses. Goggles for sports and for work in areas with excessive sunlight must be functional, comfortable, and have a high degree of protection.
    2. For relaxation and constant wear in the summer, it is recommended to choose glasses of 1 and 2 light transmission category.
    3. Photochromic and graduated glasses are easy to use; polarized, blocking bright light, better suited for winter holidays in the mountains and summer - by the sea.
    4. If vision correction is required, wear protective glasses at the ophthalmologist's office.
    5. When purchasing sunglasses, inquire about the reputation of the manufacturer and check for a certificate of quality.
    6. Sunglasses should be bought not in the market, but in the shopping centers "Optics" and specialized departments of tourist shops.

    How to choose sunglasses

    1. Sunglasses should be comfortable. The size and shape of the frame only matters from this point of view.
    2. The sunglasses model is highly recommended to be selected for a specific purpose: sports, work, leisure or constant wear.
    3. Before purchasing sunglasses with lenses of exotic colors, it is worth asking if it will harm your eyesight.
    4. Sunglasses with narrow or round lenses in small sizes will not provide UV protection, nor will sunglasses that are too dark without a UV reflective coating.
    5. Cosmetic glasses are both protection from the active sun and a fashion accessory. It is advisable to choose their shape and frame color in accordance with the type of face and preferences in the style of clothing.
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