Socializing in virtual reality sounds geeky, and it is. But starting this week, social VR startup AltspaceVR is making what feels like an important incremental step to mainstream acceptance: Tracking its users’ eyes.

The premise of Altspace is that people will want to be able to talk and share content from around the Web together in VR. So rather than emailing your old college roommate a link to that new funny YouTube video, you might both slip into VR goggles and watch it simultaneously on a simulated TV screen, and then — still in the VR world — turn to each other to talk about it.

As it turns out, we say a lot without words, something actors and animators have known forever.

“You can see if someone’s rolling their eyes, see if they’re looking away,” co-founder Bruce Wooden said. “You can look in a certain direction to see who’s talking.”

Re/code recently got an exclusive preview of how eye tracking might affect social interactions in VR. This video was captured by a “camera bot” inside of Altspace, while Wooden (on the left) and I (on the right) were in the same virtual room as the bot, each of us wearing an Oculus Rift headset:

https://www.youtube.com/watch?v=zRfthZaBBPY

Wooden noted that eye-tracking may partly or totally replace the mouse and keyboard, which are difficult to use when your vision is occluded by a set of goggles. That matters a lot to AltspaceVR, because its users need an easy way to browse the Web and find that YouTube video in the first place.

“The eyes can focus on a very small pixel range, like a YouTube ‘play’ button,” Wooden said. “We’re getting into territory where I don’t even know how to describe this stuff.”

The eye-tracking tech won’t be available to most people, even the developers who already own VR headsets, right away. AltspaceVR is currently using customized Oculus Rift prototype headsets, on loan from the German eye-tracking company SensoMotoric Instruments GmbH.

SMI sells an upgrade package to add eye tracking to the Oculus Rift DK2, a developer prototype of the VR headset released more than a year ago. Reached via email, SMI’s OEM business director Christian Villwock confirmed that the company is considering something similar for the consumer version of the Rift, due out next year.

Villwock also noted that SMI is talking with “all major HMD companies to explore integration options.” Sony’s Magic Lab, the origin of the PlayStation VR headset Project Morpheus, was experimenting with an SMI eye-tracking sensor when we visited in November, albeit a standard one placed in front of a 2-D monitor rather than inside a 3-D headset.

And, of course, interacting with another VR avatar is just one use case for eye-tracking. Villwock said it might also “measure cognitive workload,” reduce nausea by calibrating an image to where the user is looking and “measure ad effectiveness and information placement.”