I’ve only seen this in fictional settings, so sorry if this should have been in cafe society.
This features in AFAIR both Hap and Leonard season 1 and Logan Lucky. Both times in a prison. There’s a scuffle between two minor characters, one of them breaks his glasses and uses the sharp edge of the hinges to nick a carotid artery.
Does anybody know if there’s a real world case the writers took this from? And if not, is it plausible? How deep are the carotid arteries under the skin?
I’m not sure what you’re looking for, but looking at the hinges of my own glasses, I can’t see anything sharp. They seem to be a dovetail arrangement of circles, pierced by a screw that holds the arms and the lenses together.
Maybe you’re thinking about a broken glass lens, in which case a shard could be sharp?
My current cheapo glasses don’t but, year ago, my glasses would have a thick wire embedded in the resin arms to help hold a curved shape. Or, if you had metal frames, breaking the arm of would give you straight bit of metal. I’m guessing that’s what’s supposed to be getting stabbed into someone. I agree that the hinge itself seems pretty harmless.
I don’t know about real life but something similar happens in The Godfather Part 3
You wouldn’t stab a guy with glasses, would you?
It looks like the closest surface of the common carotid is almost an inch below the skin:
A sharp temple piece from a pair of eyeglasses might be able to create a problematic puncture wound, but ISTM you’d need a cutting tool to properly slice open the carotid and get someone to bleed out very rapidly.
The jugular vein is a bit closer to the skin, but of course it’s at lower pressure, so bleeding would be more slow.
If all you’ve got is a puncturing weapon, then you would need to do a “Basic Instinct” attack and make a lot of holes.
Interesting. I found the clip on youtube. It’s very quick and blurry, so hard to make out the details, but it looks like the killer just folds the glasses and jab with the edge of the frame.
Just to add to your list of fictional portrayals, in the HBO series Oz, one character stabbed another with the sharpened temple arm of his eyeglasses, though he didn’t succeed in killing the guy.
On the frame in the image here, the metal where the screw attaches could plausible nick a vein open. Not an artery though. It would be something you would only use as a weapon if all other options were under strict control, such as a prison.
Ha! 
You might be able to hack a superficial vein with that, but those tend to be smaller and not likely to lead to dangerous exsanguination before first aid can be provided. The frame of the glasses will keep those hinge knuckles from penetrating more than a fraction of an inch beneath the skin, preventing it from reaching the bigger deep veins.
Was it one of the first episodes? I tried getting into the show once I had HBO, but didn’t get far. I mentioned Logan Lucky, but can’t find mention of any prison murder in the synopsis, though it do of course have some very memorable scenes set in prison. So my memory may have replaced one prison based media for another I enjoyed more.
Third season, based on a Google search.
Have hinges on broken pair of glasses ever been used as murder weapons?
Well, they’ve been used to help convict someone of murder.
From here:
(Leopold and Loeb) may never have been caught but for ‘the hand of god at work in this case’ according to the prosecutor. A pair of tortoiseshell spectacles were found at the scene which, at first, seemed quite ordinary. When Leopold read of the find, he became worried when he could not locate his similar-looking pair in the jacket pocket in which he kept them. He had only worn them for a few weeks months earlier to cope with headaches. He consoled himself, as he recounted later, telling Loeb, ‘I know the prescription is a very common one. The doc told me so. And how are they going to know what oculist they come from? They’d have to go through the records of every oculist in town and then check on a couple of thousand people.’
But on closer inspection the frame had an unusual hinge which enabled it to be traced to a single Chicago optometrist, Emil Deutsch. The hinge was manufactured by a New York company that had only one Chicago outlet, Almer Coe & Co, and they had sold only three of the frames with this hinge. One wearer was female, another travelling in Europe at the time, the third belonging to Leopold.
(Emphasis added)