Transitions® XTRActive® lenses are designed to be worn in replacement of clear lenses yet provide more protection from light outdoors, indoors, and even in the car compared to clear lenses. They darken behind the windshield to protect eyes from sunlight while driving but are not a replacement for polarized sunglasses (which can reduce blinding glare).
Transitions® XTRActive® lenses have an average darkness of 53% and can achieve up to category 2 darkness* behind the windshield to protect eyes from sunlight while driving.
The performance of Transitions® XTRActive® lenses behind the windshield may be influenced by a variety of factors, including temperature, the position of the driver in the car, the shape and inclination of the windshield, and characteristics of the windshield.
*Transitions Optical, Inc. Real World Measurements, (2012-2013), average of Transitions® XTRActive® grey and brown. Category 2 darkness is defined as a range between 57% and 82% tint; European Standard reference