What sunglasses should be: lens materials and frames

Why is it important to choose sunglasses, which qualitatively protect from ultraviolet radiation? If the lenses are simply dark, but do not contain a UV filter, you can damage your eyesight. With dark glasses, the pupils of the eyes dilate. When UV protection is poor or non-existent, harmful radiation penetrates through the lenses. Because the pupil is dilated, more UV rays reach the tissues of the eye, damaging them. What should be the lens materials and frames of sunglasses?

Materials of sunglasses lenses

Sunglass lenses come in two types of materials:

• glass;
• plastic.

If the glasses are cheap, it is better to choose a model with glass lenses. It is more likely that UV protection will be applied to them. Full isolation from ultraviolet radiation gives glasses with the marking UV400. The smaller the number of the marking, the lower the level of radiation filtration.

Another important indicator of the lenses of glasses is the ability to transmit light. It is indicated on the ear of the glasses or in the certificate and is indicated by numbers:

• 0 - permeability of 80-100% of light. These are transparent glasses worn by athletes, drivers for protection from dust and small grains of sand.
• 1 - permeability of 80-43% of light. These are lenses with slight darkening. They are suitable for use in cloudy weather and low sun activity.
• 2 - permeability of 43-18% of light. This darkening is considered medium. Lenses labeled «2» are suitable for variable cloudiness. They are comfortable for drivers, as they are not too darkened and give a good view of surrounding objects.
• 3 - 18-8% light penetration. This is a high degree of protection from the sun. Such glasses are suitable for the beach, a walk in the mountains, for an area where the sun is very bright. They can be worn by drivers.
• 4 - permeability of 8-3 % of light. These glasses are as darkened as possible. They are worn on snowy mountain tops. They are not suitable for driving, as traffic light colors and small objects may not be visible in them.

For normal summer weather with moderate solar activity, sunglasses with lenses of medium darkness and UV protection are suitable. At sea or in the mountains you need glasses with the maximum level of radiation filtration. The lenses should be heavily darkened or with mirror coating.

Eyes are less fatigued if the lenses are polarized. They reduce the intensity of glare from sunlight. The color of the lenses does not affect UV protection. It can be not only dark brown, brown, but also gray, green or yellow.

Sunglasses frame materials

Frames for sunglasses are made of the following materials:

• Cellulose acetate plastic lends itself even to forming complex frame shapes.
• Metal thin frames made of steel, titanium or aluminum look sleek. However, metals can stain the skin, especially aluminum if it is not insulated with a special coating.
• Polyamide, grilamide is a flexible plastic that is often used for sports glasses frames.
• Optil and other epoxy resin materials. Pieces of fabric, beads, metal, paper and other decorative elements can be placed in optil frames.
• Horn frames made of natural animal horn are expensive and look rich.

What the frame is made of affects not only the appearance of glasses, but also the feeling. If it is made of cheap plastic with a chemical odor, it will be unpleasant to wear them. This can be detrimental to health. Quality materials do not emit odor, do not soften from the sun.