In the early history of Persol, when the glasses were produced in small volumes, the company also offered more than four different sizes for each pair of glasses, bridges of various heights and widths and arms of various lengths – all in the name of making each pair of glasses essentially “made to measure” so they would be as comfortable as possible.

Particular care is still devoted to evenly distribute the weight of the glasses across their entire surface through a special process called “telatura” that consists of eliminating edges on the underside of the bridge to make the fit more comfortable. This manual process was first introduced when Persol founder Giuseppi Ratti still ran the company and is still applied with the same precision and attention today.

Research into comfort also led Persol to create a foldable acetate frame in the 1960s, perhaps the first of its kind.