Several people who have seen the glasses, but who are not allowed to speak publicly about them, said that the location information was a major feature of the glasses. Through the built-in camera on the glasses, Google will be able to stream images to its rack computers and return augmented reality information to the person wearing them. For instance, a person looking at a landmark could see detailed historical information and comments about it left by friends. If facial recognition software becomes accurate enough, the glasses could remind a wearer of when and how he met the vaguely familiar person standing in front of him at a party. They might also be used for virtual reality games that use the real world as the playground.

People flailing their arms in midair as they play those games is a potentially humorous outcome of the virtual reality glasses. In a more serious vein is the almost certain possibility of privacy issues and ubiquitous advertisements. When someone is meeting a person for the first time, for example, Google could hypothetically match the person’s face and tell people how many friends they share in common on social networks.

This month, the Electronic Privacy Information Center, a research and advocacy group for Internet privacy, asked the Federal Trade Commission to suspend the use of facial recognition software until the government could come up with adequate safeguards and privacy standards to protect citizens.

Mr. Brinkman said he was very excited by the possibilities of the glasses, but acknowledged that the augmented reality glasses could pose some ethical issues.

“In addition to privacy, it’s also going to change real-world advertising, where companies can virtually place ads over other people’s ads,” he said. “I’m really interested in seeing how the government can successfully regulate augmented reality in this sense. They are not really going to know what people are seeing behind those glasses.”