Teen has to stay awake for four days to fight eyeball-eating amoeba

Jessica Greaney thought she only had an eye infection but that infection turned out to be a parasite living inside her eyeball.

According to IFLScience, at first Greaney's eye was sore and her eyelid kept drooping - but  "by the end of the week, my eye was bulging, and it looked like a huge red golf ball", Greaney said.

After being admitted to the hospital, doctors identified Acanthamoeba in her eyeball.

Acanthamoeba are actually one of the most common protozoa, being found in soil and water where they help break down nutrients.

If they get into humans they are trouble.

Because the amoeba was in Greaney's eye it caused amoebic keratitis, which can lead to corneal ulcers or blindness if left untreated.

This often happens to people who wear contact lenses who don't properly disinfect them. Multipurpose lens solutions mostly don't work against the amoeba, but hydrogen peroxide-based solutions do.

Greaney had to stay awake for the next four days - putting eye drops in her eye every thirty minutes.

"Four nights of not being able to sleep sounds like torture and it is. It's really heartbreaking and hard to go through," she said.

"Although it's hard, it is worth it in the end because I'd rather go through four nights of not being able to sleep than not being able to see for the rest of my life."