Recently discovered patent information suggests that Google may begin using Google Glass to track consumers’ reactions to advertisements. Glass can identify an ad and judge a person’s response by monitoring pupil dilation. This technology could help Google develop a “pay per gaze” system where advertisers get charged each time an ad is viewed through Glass. However, recent reports have indicated that personal data collected from Google Glass apps would not be sold for advertising or marketing purposes.

While monitoring people’s reactions to an array of advertisements could be helpful to advertisers, news of the patent comes as a surprise, since the terms of service for the Google Mirror API that lets developers build apps for Google Glass forbids ads on the device.

“We hold patents on a variety of ideas,” responds a Google spokesman. “Some of those ideas later mature into real products or services, some don’t. Prospective product announcements should not necessarily be inferred from our patents.”

“Providing a robust data set will be tough considering how few people currently have Glass. Currently there are only about 10,000 of these devices in the world,” reports Advertising Age.

However, the “pay per gaze” system is a unique idea. If implemented, it could change the way advertisers operate.

“‘Pay per gaze’ would function as its name implies: every time an ad is registered as viewed on Google Glass, the advertiser gets charged. Those views are then connected to the people’s emotional responses to the ad as determined by how dilated their pupils were at that given time,” explains the article.

The approach is not limited to online ads, but could also potentially apply to billboards, magazines, newspapers and other forms of conventional print media.

The information gathered from Glass would include how long a person looked at an ad, how many people saw the ad at one time, and whether or not a person looked at an ad multiple times.