And Ray Gallagher, a British seller who has been in the optical business since 1963, has seen sales at his online store The Monocle Shop double over the last five years.

Martin Raymond, a British trend forecaster, credits the rise to what he calls “the new gents,” a hipster subspecies who have been adding monocles to their bespoke tweed and distressed-boot outfits. On a recent trip to Cape Town, Mr. Raymond said, he saw such a group carrying monocles along with tiny brass telescopes kept in satchels.

“All of this is part of a sense of irony and a way of discovering and displaying old artisanal and craft-based technology,” Mr. Raymond said. “You see the monocle appearing in Berlin, parts of South Dublin.”

Toby Miller, a cultural historian, said: “Monocles have always marked people out as beyond the crowd, slightly different. On one hand you have the Prussian officer, on the other you have the effete English lord, and then you also have the New York and London lesbian in the 1920s.”

Monocles are hardly everywhere. You won’t find them at the J. Crew Liquor Store, Topman or even at the on-trend stores run by Monocle magazine.