UV and Visible Light:
lPhotochromic molecules are the "magic" technology inside each Transitions lens. As you experience different lighting conditions throughout your day, the molecules adapt by changing structure. This automatic change causes the lens to get darker, as well as return to be as clear as an ordinary, non-photochromic lens.
The molecules are triggered to change by exposure to specific wave-lengths of light. Original Transitions lenses are activated by UV light. This is why the lens activates when outdoors but not indoors. Transitions XTRActive lenses are activated by UV light as well as visible wavelengths of purple and blue light giving the lens slight activation indoors and increased activation behind the windshield of the car and even more activation outdoors.
The family of Transitions lens products continues to be the most advanced featuring photochromic technology and remains the best choice to enhance your ability to discern objects of varying size, brightness and contrast, giving you the gift of better sight everyday and in any light condition.
Transitions lenses employ photochromic technology to change the way you see the world. UV light from the sun causes a chemical reaction inside our lenses to produce varying degrees of darkness. On a cloudy day, in shade, or when the sun
is setting and the amount of UV light is minimal, the molecules only slightly activate. This moderate activation is intentional to allow just the right amount of light to pass through the lens to reach your eyes so that you can see clearly and comfortably, regardless of the time of day and lighting conditions.
In the presence of UV rays, our clear, polycarbonate lenses start growing darker in only a matter of seconds, typically reaching 70% activation within 35 seconds. When UV rays are no longer present, our lenses immediately begin to fade back and become clear lenses in just a few minutes.
Regardless of the amount of light present, Transitions lenses always block harmful UVA and UVB.
Reducing Eye Fatique:
In the fight to help eliminate glare and reduce eye strain, Transitions lenses are always working for you.
Low lighting conditions cause the eye to work overtime when seeing or reading and can contribute to sore, tired eyes or even headaches.
Bright lighting conditions elicit a universal reaction from the human eye; squinting. Squinting causes the pupil to constrict and is a natural attempt to block the amount of light entering the eye. This constriction of the pupil is one reason why eyes may feel strain or pain in bright light conditions.
Because photochromic lenses react to the amount of UV light exposure, Transitions lenses provide comfort and convenience by automatically adjusting to control the amount of light that reaches the eye.
Behind the Windshield:
Because the glass in car windshields blocks most UV rays, less than 1% of the available outdoor UV energy reaches the lenses of the driver. Traditional photochromic lenses just do not receive sufficient energy to provide significant darkening while driving.
For these situations, we offer an everyday lens solution, Transition® XTRActive™ lenses or, suggest drivers consider a second pair of sunglasses or a specialized product such as polarized Drivewear ® Transitions® SOLFX™ lenses. These lenses contain a specially designed photochromic dye that responds to both UV and natural (visible, clear, or white) light and can activate behind a windshield.