Google, Inc. will make its Internet-ready Google Glass available for only a limited time beginning April 15.

On this date, Google will begin what it says is the biggest expansion of the Explorer program to date by letting anyone in the US buy the eyewear online at google.com/glass/start/how-to-get-one/.

Google said online sales would take place "for a limited time," but did not specify how long that might be.

Those who do decide to part with $1,500 for a Glass will join the ranks of "Explorers" that have gotten to test the devices before the controversial product's market launch at an as yet undetermined date.

"Our Explorers are moms, artists, surgeons, rockers, and each new Explorer has brought a new perspective that is making Glass better," Google said. "But every day we get requests from those of you who haven't found a way into the program yet, and we want your feedback too."

Google in March said it is joining forces with Luxottica Group S.p.A, the Italian owners of Ray-Ban and Oakley, to create and sell Glass eyewear in the United States. Luxottica Group S.p.A. is the world's largest eyewear company, controlling over 80% of the world's major eyewear brands. Its best known brands are Ray-Ban, Oakley, Vogue-Eyewear and Persol.

The partnership with Luxottica is described as Google's biggest step yet into the emerging smart eyewear market. The first smart glasses by Luxottica for Google Glass will hit the market in 2015.

Google has been working to improve the image of Glass, which has triggered concerns about privacy since the devices are capable of capturing pictures and video.