analytics company ihs has estimated that the shipments of smart glasses may rise from just 50,000 units in 2012 to as high as 6.6 million units in 2016. according to a survey of more than 4,600 u.s. adults conducted by forrester research, around 12 percent of respondents are willing to wear google glass or other similar device if it offers a service that piques their interest. business insider's bi intelligence expects an annual sales of 21 million google glass units by 2018.