How can we use patent data for market research?

I agree with Prateek, but with one small modification. I do quite a bit of market research on new products, and patents can be very helpful because they are so well indexed compared to general literature. The things I find most useful are the companies to which the patents are assigned, the non-patent literature references, and the inventor names. All of these are good for starting points of more general searches. In addition, the backward references from a closely-matching patent, and the forward references from an older seminal patent, are good for finding other matches.

Google Scholar has done a great job of integrating patents in searches of more general literature, so that is a good place to start.

Patents are not the best way to figure out the state of the art in VR/AR for two reasons:
1) Patent applications are not made public for 18 months from they were filed. So, any developments in VR/AR in the last 18 months will not show up in publicly available patents.
2) Patents are usually not written in a reader-friendly manner. Even a trained patent professional may have to spend a couple hours reading a patent to understand what it covers. So, reading and understanding all publicly available VR/AR patents will be a very costly exercise.

I would recommend using the Wikipedia page on Augmented Reality as a starting point. The links and resources on the Augmented Reality page are useful for digging deeper into particular areas of Augmented Reality.

If you have an invention and you are wondering whether it has been done before, then a patent professional can do a patent search for your invention and tell you the state of the art as it relates to your invention.

Hope that helps. Let me know if you need more info on Augmented Reality. I worked on several augmented reality inventions back in 2012.