Last Updated Mar 15, 2016 8:34 AM EDT

Back when Google Glass appeared in 2013, Americans may not have been ready for augmented reality, and one could argue that AR wasn't ready for Americans.

But a lot has changed in just a few years, including how companies are approaching AR and the applications they're developing for the field, which is related to virtual reality but has some significant differences.

For one, virtual reality blocks people from actual reality, thanks to headsets like Oculus Rift. Gamers love VR because of its immersive experience. Augmented reality differs by overlaying digital information on top of what people are actually experiencing.

"Today's devices are capable of very cool things. They can be used in various fields, for instance education," said Yoni Nevo, the chief executive ofCimagine, which creates augmented reality products for the retail industry. "If you are studying anatomy, then you can look at the book and the image turns into 3D, and you can manipulate it."

He added, "Augmented reality will change everything in our lives in a few years, but it's starting now."

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That isn't lost on investors, who have poured $3.5 billion of venture money into augmented and virtual reality companies during the past two years, according to a recent report by analysts at Goldman Sachs. The opportunity is much vaster, especially for augmented reality, according to Nevo, who cites a forecast from Digi-Capital that AR will be a $120 billion market by 2020, compared with $30 billion for VR.

While virtual reality has received much of the hype, that market may remain the province of gamers. On the other hand, AR may eventually reach everyone who has a smartphone or tablet. Nevo's company, for example, works with retailers to create augmented reality applications for shoppers.

"I had an issue with a Kitchen-Aid mixer. It was hard to image what it would look like in my home: Is it too big, too small, is the color right?" Nevo said. "If I could see the product in my home before I buy it, if i could click a button and see that, it would be great."

With augmented reality, a shopper interested in buying a Kitchen-Aid might rely on AR software and their camera-enabled tablet to see how the appliance will look on their counter. The tablet, in video mode, can overlay an image of the mixer into the kitchen, and the shopper can walk around while holding the tablet, getting a view of the mixer from different angles.

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In another example, Cimagine is working with Coca-Cola (KO) on using AR to help their salespeople sell vending machines, signs and other equipment.

"So far they have been only able to speak about it," Nevo said. "Now with augmented reality, they can click a button and show the customer in 3D what it'll look like. In the pilot, the results were that the salespeople with augmented reality were able to sell 20 percent more and three times faster."

AR also has applications for education, health care, real estate and fields such as engineering, according to Goldman Sachs. Applications are already developed in the health care industry, such as AccuVein, which uses a scanner to help medical professionals who are drawing blood find veins in patients' arms.

One problem with Google Glass were concerns over privacy: People worried that Glass wearers would take photos or videos of them without their knowledge. Of course, almost every consumer today is armed with a smartphone with that same capability. Because of that, the future of AR might lie in smartphones and other devices, rather than glasses, Nevo noted.

As Goldman Sachs predicts: Augmented reality and virtual reality may grow from "niche use cases to a device as ubiquitous as the smartphone."