A teenager was forced to stay awake for a week to stop a worm-like parasite which had burrowed into her eye eating her cornea and making her blind.
Jessica Greaney thought she had an eye infection which turned out to be Acanthamoeba Keratitis, a bug which was eating her eyeball, and could potentially kill her if it made its way into her spinal cord.
The Nottingham University student was not allowed to fall asleep as nurses had to administer eye drops every 10 minutes to kill the parasite.
Greaney caught the parasite after her contact lenses, which she kept on her sink in her university halls bathroom, were splashed with tap water.
One of her lenses was contaminated and the parasite survived in the area between her contact lens and her eye.
Whilst she was in hospital, doctors had to clamp open her eye and scrape off a layer with a scalpel, which was then sent away for testing.
"It was not dissimilar from Chinese water torture," the 18-year-old told student website The Tab. "After the fourth day, not only was I going insane and crying every five minutes, nothing was changing.
"This parasite was still eating my eye and even worse, my immune system was shutting down because of my lack of sleep."
Factors which increase the risk of contracting the parasite include using contaminated tap or well water on contact lenses, using homemade solutions to store and clean contacts, wearing contact lenses in a hot tub and swimming or showering while wearing lenses.