Just a splash of tap water on her contact lenses led to an amoebic infection that nearly cost 18-year-old Jessica Greaney her eyesight. (Photo: SWNS)

It sounds like something out of a terrifying science-fiction movie: An amoeba burrows into a woman’s eye, forcing her to either stay awake for days to get rid of it or lose her eyesight.

That scenario was all too real for British student Jessica Greaney. The 18-year-old splashed a drop of tap water on her contact lens and became infected with Acanthamoeba keratitis, an infection that occurs when an amoeba invades the cornea of the eye. Her eye soon swelled to the size of a golf ball. Doctors abandoned their initial diagnosis of eye herpes and treated her for the amoeba.

And if having a tiny parasite invading her cornea wasn’t enough, Greaney was forced to stay awake for seven days so doctors could administer infection-fighting eye drops every 10 minutes.

“It was not dissimilar from Chinese water torture,” she wrote in an essay for 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.”

Greaney almost lost her eyesight due to Acanthamoeba keratitis. (Photo: SWNS)

Was Greaney just the victim of an unfortunate, isolated incident? No, according to Frank Graf, OD, associate professor at the University of Nebraska Medical Center and board-certified optometrist with the Truhlsen Eye Institute. Though it is rare, Acanthamoeba keratitis is a very real infection that mostly affects contact wearers who allow tap water to come into contact with their eyes.



Related: What It’s Like To Go Blind

“Ninety percent of the cases are related to contact lens wear,” Graf tells Yahoo Health. “The amoebas are found in our regular water supply like swimming pools, hot tubs — all of these sources of water we access on a regular basis.”



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The condition is notoriously difficult to treat because it’s commonly misdiagnosed, like in Greaney’s case. In the meantime, the amoeba continues to invade the cornea. If a person goes long enough without treatment, he or she could become blind. Case in point: One Taiwanese student, Lian Kao, lost eyesight in both eyes from the amoeba after she left her contact lenses in for six months without changing them.

The good news is that Acanthamoeba keratitis is highly preventable if you practice good hygiene when it comes to your contacts. “Never use water to clean your contacts,” says Graf, adding that it’s important to clean with fresh solution each night and keep your cases clean and sanitized. “Many of the popular contact lens solutions say ‘no rub,’ but I recommend that you always rub your lenses with solution.”

Related: 8 Dangerous Contact Lens Mistakes You Don’t Know You’re Making

Switch out your contacts on a schedule recommended by your doctor — at least on a biweekly or monthly basis, depending on what kind of lenses you have. “If you can get daily wear contacts, do that,” adds Graf. “It’s the most convenient and safe because you get a new, fresh pair of contacts each day.”



Most importantly, keep your lenses away from water. Wear regular glasses in hot tubs and pools, or opt for airtight goggles if you’re a more serious swimmer and need to be able to see while in the water.

In Greaney’s case, she managed to save her eyesight and has a positive outlook on the experience, despite the tortuous treatment she endured.

“I’m still on 22 eye drops a day, but this has decreased from 41 — and hopefully will continue to decline with every hospital appointment and check-up,“ she wrote in her essay. "Even on nights out, I sometimes have to take eye drops with me in a refrigerated bag — still beats nearly being killed by a bug.”

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