Woman's Eye Sewn Shut After Parasite Ate Her Cornea She Didn't Remove Her Contacts After Falling. A Parasite Ate Her Cornea.

A 47-year-old mother from Lancashire, England, fell face-first into a wheelbarrow filled with dirt and water while caring for her horses. She washed her face afterward but left her contact lenses in. By the next morning, she couldn’t open her eyes without pain so severe it stopped her cold.

A week after that fall, Emma Marsden was diagnosed with a rare eye infection caused by a burrowing parasite in her cornea. What followed over the months after that single lapse was one of the most aggressive, treatment-resistant infections an eye can sustain. Doctors told her she also had a severe fungal infection of the cornea, Fusarium keratitis, as well as corneal ulcers. Three separate diagnoses at once, all tracing back to the same moment her contacts stayed in while contaminated water hit her face.

The organism responsible for the cornea-eating parasite infection Marsden contracted is called Acanthamoeba. It’s a single-cell organism that doesn’t need a host to survive and is commonly found in water and soil sources, which makes it deceptively ordinary in origin and extraordinarily dangerous once it reaches the eye. Most people have never heard of it. Here’s what this infection actually does, and why contact lens wearers in particular need to understand it.

The Parasite Literally Uses the Cornea as Its Food Source

Once the opportunistic parasite reaches the eye’s surface, it adheres to the cornea. If there are breaks in the corneal epithelium – a thin barrier layer of cells that are extremely sensitive to pain – those breaks allow the parasite to burrow deeper into the cornea. Contact lenses create exactly that kind of micro-damage routinely, especially when worn during any activity involving water.

Dr. Paul Barney, an optometric physician and center director of the Pacific Cataract and Laser Institute in Anchorage, Alaska, describes how the parasite adheres to the cornea’s surface, and how breaks in the corneal epithelium allow it to burrow deeper. Having Acanthamoeba keratitis “can be quite devastating if it’s not diagnosed promptly and treated aggressively,” according to Dr. Barney in a January 2026 CNN interview. “It basically uses the cornea as its food source, and that causes inflammation and tissue damage and then can eventually cause permanent loss of vision.”

Marsden’s own account of how fast this happened was striking. After the parasite had “eaten through” her cornea, her eyelids were sewn shut and she was prescribed hourly eye drops. “It eats through your eye and cornea and all your nerves,” she said. “The speed it ate at the doctors couldn’t believe it.”

Keratitis refers to inflammation of the cornea, the eye’s protective, dome-shaped outer layer that plays a key role in vision. When the cornea is compromised, vision doesn’t just blur – it can be permanently destroyed, and the eye itself can become unsalvageable, as other cases have shown.

The Acanthamoeba Cornea-Eating Parasite Is Everywhere – Including Your Tap Water

The reason this infection can follow something as mundane as washing your face is that the organism responsible doesn’t live in exotic or remote locations. A 2023 study published in the Journal of Parasitology Research collected data from 20 countries and calculated an annual incidence of 23,561 cases of Acanthamoeba keratitis – a rare but potentially blinding parasitic infection of the cornea.

Acanthamoeba, in its active form, is a microscopic organism invisible to the human eye. According to the CDC, the organism “can be found in water, soil, and dust” – which means it has a presence in swimming pools, hot tubs, rivers, and tap water used every day in ordinary sinks and showers.

The pool isn’t safe, either. Standard pool chlorination doesn’t solve the problem. Research published in the Journal of Clinical Microbiology confirms that improper contact lens care and contact with nonsterile water are known risk factors for infection. The cysts – the dormant, protective form of Acanthamoeba – are highly resistant to chemical disinfection, and chlorine at normal pool concentrations does not reliably kill them. The organism has been isolated from municipal water supplies and can tolerate normal chlorine levels in drinking water. The cyst form is essentially the parasite in armor, able to survive conditions that would kill most microorganisms.

Contact Lenses Turn a Manageable Risk Into a Serious One

About 85% to 95% of people who get infected with Acanthamoeba keratitis wear contact lenses, which create conditions favorable to the parasite. Contacts can cause corneal abrasions that provide the pathogen with a point of entry, and the parasite can also attach to the surface of a lens or become trapped between the contact and the eye, making deeper burrowing possible.

Doctors told Marsden they believed she contracted the infection by not removing her contacts while washing her face after falling into that contaminated wheelbarrow. That lapse – the delay of a few hours between exposure and lens removal – was enough for the organism to gain a foothold.

Multipurpose contact lens solutions are not a reliable defense. A 2021 study published in the journal Eye & Contact Lens found that “the anti-amoebic efficiency of popular multipurpose contact lens solutions is insufficient” to reliably prevent Acanthamoeba keratitis infection. The CDC explicitly advises that poor contact lens hygiene and wearing contacts while swimming, using a hot tub, or showering can increase the risk – and the guidance applies equally to something as routine as washing your face.

The Infection Is Routinely Misdiagnosed, and That Delay Makes Things Worse

One of the most clinically dangerous features of Acanthamoeba keratitis is how often it’s initially mistaken for something else. According to a 2024 analysis by Prevent Blindness, “many cases of AK have been misdiagnosed as herpes simplex keratitis which is treated with steroids” – and steroids actively worsen a parasitic infection, accelerating the damage.

Marsden reported that her eye was “excruciatingly painful and red,” and that when she woke up the following morning, any time light hit her eye the pain was so severe she couldn’t open her eyes. Those symptoms – intense pain, severe light sensitivity, and a very red eye – overlap closely with other corneal conditions, which is precisely why misdiagnosis is so common.

A 2021 study published in Acta Ophthalmologica found that 69% of patients with Acanthamoeba keratitis were misdiagnosed prior to getting the correct diagnosis, with most going more than 28 days before receiving appropriate treatment. A 2025 NIH-indexed study confirms that patients receiving treatment within 14 days of symptom onset generally experience better visual outcomes – meaning every week of delay carries a measurable cost.

A Second Infection Made an Already Dire Situation Worse

Marsden’s case was complicated further by a simultaneous Fusarium infection. Fusarium is a filamentous fungus – a mold-like organism – capable of penetrating the deepest layers of the cornea rapidly. In many parts of the world, Fusarium is the most commonly isolated pathogen among fungal keratitis cases, and clinical management of this infection is challenging because the first symptoms are often delayed and fungal infections are difficult to distinguish from bacterial ones on clinical grounds alone. A 2021 review published through the NIH notes that Fusarium is highly virulent and capable of penetrating the corneal stroma and Descemet’s membrane – the stroma being the thick middle layer of the cornea, and Descemet’s membrane being one of its innermost layers. Damage at that depth is not reversible with medication alone.

Fusarium keratitis has a documented history of affecting contact lens wearers specifically. Fusarium keratitis typically occurs on a damaged cornea with compromised ocular surface defenses and is frequently observed in individuals wearing hydrophilic contact lenses. A significant outbreak of Fusarium keratitis swept across the United States between 2005 and 2006, linked to a specific contact lens disinfecting solution, putting clinicians on alert – but the fungus remains a risk whenever lenses are exposed to contaminated environments.

Having both Acanthamoeba keratitis and Fusarium keratitis at the same time, alongside active corneal ulcers, put Marsden in a situation where every treatment decision was complicated by the others. According to the Cleveland Clinic, corneal ulcer symptoms include a red or bloodshot eye, watering eye, and severe eye pain – an experience Marsden described with precision.

When the Infections Win, Corneal Transplant Outcomes Are Poor

When medical treatment fails to stop Acanthamoeba keratitis, corneal transplantation – known as keratoplasty – becomes the last option. But a 2024 study in a peer-reviewed journal found that Acanthamoeba keratitis “showed the worst outcomes of all causative agents” when it came to graft survival after transplantation. Two-year graft survival for Acanthamoeba keratitis was approximately 52%, compared to 81% for bacterial keratitis – a stark gap that reflects how aggressively this infection resists resolution even at the surgical stage.

A 2025 analysis indexed by the NIH puts the scale in perspective: roughly 1,500 cases of Acanthamoeba keratitis occur in the United States each year, and a meaningful portion of those patients require transplants. The path to getting there is also long. A 2021 study in the Journal of Clinical Medicine found that treatment without stromal involvement typically lasts three to four months, and treatment with stromal involvement can extend beyond eight months.

For Marsden, her eyelids were surgically closed – sutured shut – to protect what remained of the cornea while hourly eye drops attempted to suppress both infections simultaneously. She has since urged other contact lens wearers to be more cautious. “You don’t think about the knock-on effect just by not taking your contact lenses out in the shower or to swim in, or to wash your face in my case,” she said, adding that while opticians warn people not to swim or shower in lenses, the messaging rarely conveys the real severity of what can happen.

What Every Contact Lens Wearer Should Do Now

The contact lens rules that prevent Acanthamoeba keratitis are not complicated, but they require consistency. Remove lenses before any contact with water – including washing your face, showering, and especially swimming or using a hot tub. If lenses are accidentally exposed to water, remove them immediately, disinfect with a proper contact lens solution rather than tap water, and watch for symptoms over the following days.

The first symptoms Marsden noticed were an eye that was “excruciatingly painful and red.” Severe eye pain, pronounced light sensitivity, a sensation of something stuck in the eye, and excessive tearing are all reasons to see an eye doctor the same day – not in a week. Given how frequently this infection is initially misdiagnosed, specifically asking whether Acanthamoeba has been ruled out is a reasonable and potentially sight-saving question to put to any clinician evaluating an eye that isn’t improving with standard treatment.

If you wear contacts and are ever in a situation where they come into contact with soil, dirty water, or any unfiltered natural water source, treat that exposure as an emergency. Remove the lenses as soon as possible, switch to glasses, and get an eye examination. The parasite that ate through Emma Marsden’s cornea was there the moment the dirty water hit her face. The lenses just gave it a way in.

Disclaimer: This information is not intended to be a substitute for professional medical advice, diagnosis, or treatment and is for information only. Always seek the advice of your physician or another qualified health provider with any questions about your medical condition and/or current medication. Do not disregard professional medical advice or delay seeking advice or treatment because of something you have read here.

AI Disclaimer: This article was created with the assistance of AI tools and reviewed by a human editor.

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