In order to:
collect dust on the shelf in the corridor;
lie about on the drawer;
be snapped in the bottom of a bag ;
be dropped on the floor;
rub up the nasal bridge;
and to terribly annoy .
Beside all that the purpose of sunglasses is to protect the retina from ultraviolet rays and infrared. Deciding to buy sunscreen cosmetics in the Ruble Boom and in 1b.ru stores, you, surely, have paid attention to the fact that there is no special cosmetic for protecting delicate skin around the eyes from the sun rays. Sunglasses are in charge of this.
Sunbeams destroy melanin - a natural pigment that protects eyes from outburning.
Intensive sunlight exposure can cause eye cataract and reduction of the visual acuties.
There are two types of radiation that affect the eyes:
Ultraviolet. Radiation causes aging of the skin and can provoke a retina burn;
Infrared. Radiation is increasing the effect of ultraviolet radiation, but not in a humid climate where such radiation is way below.
Plastic and glass fully protect eyes against IR radiation, but glass partially let the ultraviolet goes through. Lenses made of high quality polycarbonate are able to block UV rays completely.
Glasses with polarization help to reflect the glare of wet asphalt, water, snow, etc. These glasses are made using special technology that gets the vision sharper by eliminating glare. They are recommended for petrol heads and on vacation by the water.
Photochromic lenses help to adapt to the dark time of the day. They are recommended for those who drive in the nighttime. Chameleon glasses are using these lenses. They change the intensity of the ultraviolet rays transmission, as required.
Using photochromic lenses you should take into account:
If the lenses do not protect from ultraviolet, but have intense color, they’ll protect eyes worse than bright lenses with the rays protection.
Wearing dark glasses cause pupil dilation. Therefore, without UV rays protection such sunglasses will severely damage your eyes.
Being on the beach or just in the sunshine, you should wear a headgear along with the sunglasses, the headgear is detaining more than 50% of the radiation.
There are five types of light transmission level:
"0" - 80-100% light transmission. Radiation protection is minimal.
"1" - 43-80%. Partial UV protection, suitable for urban use.
"2" - 18-43%. Also recommended for urban
"3" - 8-18%. These glasses are suitable for the beach and outdoor recreation.
«4» - 3-8%. These glasses may be applied in the mountains and while visiting hot countries.
In order to protect the retina, read the information on the label and in the inserts.
Information indicated in the label:
light transmission level;
ultraviolet radiation protection;
How to choose sunglasses.
Experts suggest to buy sunglasses not in the market, but in stores where you can read the information in the label.
If you have eyesight problems consult your doctor.
It is advisable for drivers to buy photochromic glasses with polarization.
Square face. With this oval face, glasses can balance the image and add some softness. Large glasses with soft shapes will meet these needs.
Round face. For chubby ladies, it is netter to use glasses with square shapes that visually stretch out the face and sharpen its features. A good solution will be large glasses with square form and pointed form.
Triangular face. For girls with this form of face, glasses with "cat's eye" or retro shape. Such a form will emphasize the face oval and will not overload it.
Oval face. For this face form all types of glasses are suitable. A successful decision will be aviator glasses.
Long face. For women with a long face it will be best to use glasses of large sizes. Small glasses with a thin frame will visually enlarge the face.
You can check the polarization with a hologram. It is not visible to the naked eye and in glasses without polarization.
If you set the smartphone brightness to a maximum and choose the white color of the screen, while rotating the glasses vertically to 90 degrees turn, the lenses should darken to full opacity.