A curving confluence of lightweight acetate and sleek engineering.
Keystone features a 'panto' lens shape and pear tip temples, and is available in two sizes, nine colours, optical and sun.
It takes its name from the glorious Keystone Crescent in King’s Cross, a falciform of Georgian architecture, and the smallest radius of any crescent in Europe.
Once home to The Caledonian Asylum for Scottish Children before the crescent was built in 1846, it sits at the heart of the King's Cross conservation area.
Under its cobbled feet is a private members bar, where alcohol flows into the early hours.
But deeper still, flows the lost River Fleet, which “weaves through King’s Cross’ spaghetti junction at a depth between the Victoria line and the Northern line.”