If you're running Android 11 DP2, and you have a Pixel 4, you can now go into settings and toggle this on or off at your leisure.
This is of course only available on the Pixel 4 since no previous Pixel devices have the Face Unlock that's powered by the Soli radar chip. It's also not available yet on any devices running on Android 10. Which means you will need to install the preview to access it.
The Pixel 4 'Eyes Open' toggle was supposed to launch months ago
Although the feature is now live for use with anyone that has a Pixel 4 running on Android 11 DP2, it was supposed to launch months ago.
Many thought that it would actually be available soon after the launch of the Pixel 4. But that wasn't the case. The issue stems from the launch of the phone when users discovered that the Face Unlock option would still unlock devices even if eyes were closed.
For anyone on Android 10 this is still how the feature works. Which makes a little bit of a security issue and one that Google received a fair bit of scrutiny over.
Since the feature is live with the second version of the developer preview of Android 11, it seems like the feature won't launch completely until Android 11 launches later this year.
How to access it
If you're running the Pixel 4 with the second developer preview then you may already know how to access the feature. On the off chance you don't, it's not too hard to get to.
Simply enter the settings menu and scroll to security. Once inside the security sub-menu, scroll down to Face Unlock and tap on that.
Once there you should find the toggle for the Eyes Open function in the requirements section, just above the always require confirmation toggle. As the description on the option says, the phone will require your eyes to be open before it unlocks.
It reportedly works just as it's supposed to which should mean some peace of mind for anyone that doesn't care for the feature being unavailable. If you're planning on installing the second developer preview of Android 11 just to get a hold of this, keep in mind that it's a developer preview for a reason.
Google doesn't intend these builds of software to be for end users. It's quite likely there are still a fair number of things that won't work properly.