Photochromic lenses promise to protect our eyes from UV Rays 100% (Ultraviolent rays) - though only when they came into connection with sunlight. Or else, the lenses remain clear.

What exactly Photochromic Polarized Sunglasses are?

Photochromic lenses are also called dye lenses.

These lenses get darken in bright light conditions.

Photochromic lenses can provide slight dye if required. They change their color depending on how the glittering light is. Therefore, the photochromic shades will only get darken slightly in certain circumstances, for example when the room is brighten by the sunlight.

With 100% UV protection these glasses insure that your eyes remain healthy and cozy all year round.

Working of photochromic lenses..

These shades work with molecules. Silver halide and sliver chloride molecules are responsible for the lenses to change colors so that they can dim in bright light conditions and get clear in indoors.

When these sunglasses lenses are revealed to UV light, Temporarily trillion of  photochromic molecules start to change structure. Once the form of huge number of molecules changes all together, the surface of the lens darkens.    

Advantages of Photochromic sunglasses.

 

• It will give you a healthier life and a preferable sleep.
• Provides comfortable vision all-day.
• Offer 100% protection against UVA/UVB rays.
• These lenses adopt to environment changes (Indoor, Outdoor, High or Low Brightness).
• They are available in different colors.
• They provide day to day protection against UVA/UVB rays by absorbing them

Source: Here is the site from where you can buy a Photochromic sunglasses in reasonable price.

1. Soxick:

 

                   

KTY Photochromic Polarized Sunglasses - GB

$39.99