Frameri, an American startup known for its interchangeable lenses and frames, has closed down. The co-founders of the Cincinnati-based firm, Konrad Billetz and Kevin Habich, started the company in 2012 but famously turned down an offer from an investor on the television program “Shark Tank,” opting for a partnership in 2016 with Hoya Vision Care. At the time, Hoya and Frameri said the product would soon be available in 500 independent eye care practices across the U.S.