When Transitions lenses are exposed to UV light, trillions of photochromic molecules in the lens begin to change structure. This reaction is what causes the lenses to darken.

Only Transitions lenses use exclusive technology, from patented formulas that are the result of more than 20 years of research and innovation. Each formula is integrated into the surface of the lens. These molecules constantly and smoothly recalibrate so the optimal amount of light reaches your eyes whether you’re in bright sunlight, under cloud cover or indoors.


Transitions Optical’s photochromic technology becomes an integral part of the lens through one of two proprietary processes.

One process is called imbibing. Derived from the Latin word imbibere meaning, to drink in, this method uses heat to draw the photochromic dye into the lens itself. After the imbibing is complete, a scratch-resistant coating is applied to the surface of the lens.

A number of lens materials do not imbibe readily. In these cases, another method called Trans-Bonding™is used. Where imbibing places the photochromic technology below the lens surface, the patented Trans-Bonding puts the photochromic technology on the lens surface.

Unlike the method used by some other type of photochromic lenses, both imbibing and Trans-Bonding methods provide the same uniform tint colour across the surface of the lens, regardless of lens thickness differences caused by lens prescriptions. At Transitions Optical we develop and adapt our processes for optimum photochromic performance, lens durability and compatibility with other lens treatments such as anti-reflective coating.

Transitions Optical is the only optical company that has its proprietary photochromic technology. That’s why we are a trusted worldwide leader: one Transitions lens is sold every second around the world.


The glass in car windscreens blocks more than 99% of UV light, so most photochromic lenses do not darken noticeably in the car.

We offer an everyday lens solution: Transitions XTRActive lenses contain a specially designed photochromic formula that responds to both UV light and short wavelength visible light, so they are able to adapt in the car.

If you are seeking the ultimate driving experience, we recommend a pair of Drivewear Transitions adaptive lenses.