Earlier this year it was reported that Apple is developing augmented reality features that will eventually appear in glasses after coming first to iPhones. Now a newly leaked document may have accidentally acknowledged Apple’s prototype AR glasses for the first time.

Gizmodo reports that it has acquired a safety incident document accidentally distributed to Apple employees that mentions a prototype device that has caused eye strain for testers.

Incidents in the report appear to have occurred in February and March which offers a timeline for the possible AR glasses prototype testing based on the document’s title: Impact Descriptions Reported in [Santa Clara Valley] from Last Month.

Specifically, two incidents cited refer to a prototype relating to eyes that caused issues. The first occurred in late February:

The second incident occurred a few days later in the following month:

Gizmodo reports that its source within Apple believes the prototype mentioned may be related to the AR glasses product that is being developed internally. Apple’s AR glasses project is said to be at least a year away from launching.

The report also details other curious and rather random incidents including an employee opening a problematic box of Apple Pencils with bad batteries:

Another employee reported a knee injury when skiing in the Tahoe area to test Apple Watch functionality which sounds like a job that might be worth the occasional bumped knee.

You can read the full piece here. At any rate, Tim Cook has certainly made it no secret that Apple has plans for AR in some form or another (and its take on Google Glass may be causing a few issues in its current prototype state).