The phrase "eye stroke" has recently appeared in news reports about a very rare side-effect of weight-loss injections. It's not a formal medical diagnosis, but a shorthand used to describe a condition in which reduced blood flow damages the optic nerve and causes sudden vision loss. The phrase might be misleading. Unlike a conventional stroke – which can cause someone to lose the ability to move their limbs or speak – an eye stroke can be harder to recognise at first. Vision can be lost