Transitions lenses: Behind the scenes of the latest lens technology

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As someone who has worn glasses for more than two decades, I’m well-versed in the ways that eyewear can either enhance your lifestyle or hold you back – particularly if you don’t want to (or can’t) wear contact lenses. 

One pain point is ensuring that your eyes are protected in bright light or outdoor settings. Enter Transitions lenses, which offer an alternative to having to swap between eyeglasses and sunglasses as they change colour when exposed to UV light. 

The lenses have come a long way from their early days as adaptive eyewear primarily used by seniors, and their new Gen S lenses offer more flexibility and style options than ever. I recently had the opportunity to visit one of the brand’s manufacturing facilities in Tuam, Ireland to discover the new lens technology and see for myself how they’re made. Here’s what I learned:

Transitions Gen S lenses are equipped with patented photochromic dyes that enable them to rapidly darken when they are exposed to the sun’s ultraviolet light. The greater the intensity of UV rays, the darker the lenses become. When UV light is no longer present, including indoors or at night, the lenses fade back to their original clear finish. 

While previous generations of Transitions lenses could take several minutes to transition between clear and tinted, Gen S lenses take seconds. In tests, they were able to reach category three levels of darkness within 25 seconds of exposure to UV light and fade back to clear in under two minutes.

While the exact specifics surrounding the Gen S lens technology are kept under a tight lid (no photos were even allowed inside the factory), I did get to witness the journey that the lenses undertake as they pass through the facilities.  

The lenses start as what looks like a clear hockey puck. These semi-finished lenses then journey along a conveyor belt that takes them through the entirely automated coating process. 

First, the photochromic dye is applied to each lens. This occurs while the lenses are spinning, which ensures it’s applied in a thin, even layer. Next, the lenses are cured and cleaned, and the process repeats itself as protective layers are applied on top of the coloured dye. Depending on the chemicals used in each layer, the curing process may involve UV light, thermoregulation or electromagnetism. 

Once completely coated, cured and cleaned, each lens undergoes a strict quality assurance test – the only time during the process that human hands are involved. Lenses that pass the test are sent away for finishing, where they will be cut and shaped to fit a particular glasses frame and prescription. 

While some lenses have restrictions on prescription strength compatibility, that’s not the case with Transitions Gen S lenses. They can be used with both prescription and non-prescription lenses, as well as with progressive lenses. The lenses are also suitable for glasses wearers of all ages. 

In addition to being more reactive and responsive to changing light conditions than previous Transitions lenses, Gen S lenses block 100 per cent of UVA and UVB rays and filter up to 85 per cent of blue violet light when activated (up to 32 per cent of blue light is blocked when clear). 

The lenses are available in eight unique colours: ruby, gray, graphite green, amethyst, sapphire, emerald, amber and brown. On average, the lenses will cost around $100 more than standard glasses lenses. 

Because the photochromic dye reacts more quickly in warmer temperatures, you may find that the lenses take longer to transition between clear and tinted in cold weather – definitely something to consider if you spend a lot of time outdoors in the winter. They also don’t activate from behind the wheel (car windshields are designed to block most UV light, negating the effects of Gen S lenses) – drivers may want to consider Transitions Drivewear lenses instead. 

If you’re looking to purchase a pair of new lenses, you can shop Transitions lenses online at:

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