That's what Yannick Lozac'h found at a recent visit to a Sunglass Hut in Manhattan. The 33-year-old Paris-based engineer spent 20 minutes trying on about a dozen styles before leaving the store empty-handed.

"I don't like buying sunglasses," Lozac'h, who has a long face, says. "It's hard to find the right fit."

He's not alone.

"Finding sunglasses can be challenging," says Michael Hansen, senior vice president and general manager of Ilori, a boutique chain offering high-end designer sunglasses. "People will sometimes choose to have a certain style and base their decisions on the style rather than the fit. That's not always the best for them in the long term."