Whether you’re reading state secrets or some badly written fanfiction, there’s nothing worse than the feeling that somebody is reading over your shoulder. And this is something that Apple may be tackling in a future iPhone, reading between the lines of a new patent application uncovered by Patently Apple.

While the majority of the text discusses how Face ID profiles could be adjusted for different degrees of visual impairment, the really interesting stuff comes in a section about “privacy eyewear.” In short, your screen will appear garbled to everyone except the person wearing said eyewear. Which is hopefully you, unless you really shouldn’t be trusted with secrets.

“In some embodiments, a user may interact with the calibration graphic… to intentionally blur the graphical output presented on the display,” the application reads. “For example, if a user desires privacy or does not want a nearby person to view what is presented on the display… the user may interact with the calibration graphic… to make the graphical output illegible.”

No hardware is mentioned in the text, of course, but a device in one of the diagrams looks an awful lot like an iPhone, with the section where Face ID currently sits seemingly recognising the wearer. Or at least silently judging the choice of spectacles.

Apple has long been rumoured to be working on smart glasses, of course, and this sounds like a genuinely useful purpose for them. Far better than anything that Google Glass or Facebook’s Ray Ban collaboration has offered to date.

Hopefully Apple Glasses will actually look quite fashionable, though. The thrill of reading top secret documents in public will be somewhat undermined if you look like you’re a 1990s movie goer who forgot to return the 3D glasses after the show. Although even if that is the case, no doubt Apple can make people override their senses and make it a popular look anyway

Not all patents come to fruition, of course, and even if this does, we’re still a long way off the first Apple eyewear appearing on eager early adopters’ faces. Rumour has it we’re looking at 2023 at the earliest, and possibly much later than that.