Google Glass users will soon see ads that are charged to advertisers on a “pay per gaze” contingency. Google has filed a patent for its new technology, which will work in both online and offline modes.

The patent was granted to the tech giant on Tuesday.

Google doesn’t specifically list Google Glass, but it does note that the “gaze tracking system” requires a “head mounted gaze tracking device” which “comprises eyeglasses” and includes “side-arms that engage ears of the user… lenses through which the user views the external scenes, wherein the scene images are captured in real-time” as well as “at least one forward facing scene camera.”

Google, in the past, said it would ban developers from displaying ads on the device. Google has not yet revealed the patented technology and how its per per gaze system will play a part in app display advertising.

To track when a user looks at each ad, Google will implement gaze-tracking to pinpoint when an ad view actually occurs.

According to the patent, the system will identify not only if but also when an advertisement is viewed. Google will charge advertisers “based at least in part on a per gaze basis.” The search giant may also charge a fee based on how long a users gaze is kept on the ad.

That’s not even the crazy part. Google is also said to be implementing a piece of tech that can grab information based on pupil dilation information. In layman’s terms, Google will be able to track a customers emotions based on their eye responses. Based on a user’s emotional response, ads could be more expensive for advertisers.

Don’t worry too much for your privacy since Google states in the patent that “personal identifying data may be removed from the data and provided to the advertisers as anonymous analytics.”

The patent also mentions the possibility for an opt-in, opt-out option.