Photochromatic lenses have been around for some time and are great for rides where the light changes gradually, such as dawn/dusk missions. However, they can struggle to keep up with fast changes in contrasting light, and even the quickest of the lenses can take the better part of a minute to darken and then up to 15 minutes to clear back up.
French startup Juic-e may have solved this problem with a new lens technology that claims to fully swap in .01 of a second. However, the brand says it has slowed the process down 0.8 of a second “for physiological reasons related to the human eye and to avoid stroboscopic effects.”
The Spic-e T sunnies' lenses also change colour from a light yellow/orange to a dark brown, which the brand says also improves contrast.
I can see the quick change being especially useful in a high-contrast environment such as singletrack, which winds in and out of trees, or during late afternoon where going from long shadows to full sun can have quite a dazzling effect.
If you watch to the end (past the rendered lenses) you can actually see the lens change. Even in slow motion it's fast
Juic-e is not the first brand to develop something like this, Uvex released its Variotronic S lenses, which also boast a 0.1 second charge time, but this reaction is powered by an electric charge that requires an internal battery — and this needs to be recharged and uses a button to activate the change.
Juic-e on the other hand has worked out how to facilitate these changes in the tint without a battery and its system is completely automatic, reacting to the light conditions in your environment.
The glasses are quite ‘euro’ in appearance and consist of the battery free ‘eletrochromatic shield’ that appears to be two lenses bonded together, and a photochromic sensor which is built into the nosepiece.
Juic-e also says its sensor is sensitive to luminosity through the entire light spectrum, rather than just UV like most standard photochromic lenses.
When a normal photochromic lens changes tint it undergoes a thermal process, and hot weather can prevent the lens darkening all the way. Conversely, in the cold, they can also take longer to fade back to clear. Juic-e says its new lenses are completely unaffected by temperature at either extreme.
Unfortunately, as with most new technology, the Spic-e T sunnies cost an arm and a leg and are set to retail for €390. But for the early adopters, there are early special offers to be had.