Teresa Sanchez was in Mexico for a medical procedure nearly four years ago when she kept feeling dry, poking sensations in her right eye.
She chalked it up to a potential rip in her contact lens, the general dryness she had felt since she started wearing monthly contacts instead of dailies or her body possibly fighting off an illness.
But what she wouldn’t know for another three months was that a little invader was waging war against her cornea, permanently destroying her vision and causing intense, burning pain that radiated throughout her head.
“I couldn’t have my blinds open in my room, because that would trigger really, really bad pain in my eye,” Sanchez, 33 and based in Las Vegas, said of a harrowing moment after about three months of being misdiagnosed by optometrists. “That’s how I knew it was something serious, and I started doing my own research.”
Sanchez learned online that her symptoms appeared consistent with those of a rare disease, acanthamoeba keratitis. An eye specialist later confirmed Sanchez’s suspicion. Keratitis refers to inflammation of the cornea, the eye’s protective, dome-shaped outer layer that plays a key role in vision.
Acanthamoeba, a single-cell organism that doesn’t need a host to survive and is commonly found in water and soil sources, is one of many pathogens or microbes that can cause keratitis, said Dr. Jacob Lorenzo-Morales, professor of parasitology at the University of La Laguna in Spain, via email.
Once the opportunistic parasite is on the eye’s surface, it adheres to the cornea, said Dr. Paul Barney, an optometric physician and center director of the Pacific Cataract and Laser Institute in Anchorage, Alaska. If there are breaks in the corneal epithelium — a thin, barrier layer of cells that are extremely sensitive to pain — they allow the parasite to burrow into the cornea, Barney said.
Acanthamoeba keratitis is a rare disease, noted Barney, also a trustee of the American Optometric Association. There are over 23,000 cases worldwide annually, according to 2023 data on just 20 countries, including Brazil, Canada, the United Kingdom, India and the United States.
But it’s worth noting that about 85% to 95% of the people who get infected wear contact lenses, which create conditions favorable to acanthamoeba. Contacts can cause those corneal abrasions that provide the pathogen with a point of entry; acanthamoeba can also hitch a ride on the surface of a lens or become trapped between a contact and the eye, making burrowing deeper possible.
Having acanthamoeba keratitis “can be quite devastating if it’s not diagnosed promptly and treated aggressively,” Barney said. “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.” Some patients’ vision can be somewhat restored with proper treatment or fully resolved by getting a cornea transplant.
The hardy parasite is also highly attuned to threats and responds with formidable defense mechanisms — prolonging a treatment process that’s already months to years long and often fraught with other hurdles and pain. Because of acanthamoeba’s extraordinary resilience and the eye’s sensitivity, working closely with your eye professional and following their guidance is crucial.
Diagnosing acanthamoeba keratitis early on can be challenging for a few reasons.
The rarity of the condition means many optometrists don’t know about it — which likely explains why many contact lens wearers never hear about acanthamoeba keratitis until they contract it themselves or see viral social media posts on the condition, such as Sanchez’s TikTok video. Many contact-wearing commenters on these posts say they are shocked they had never been warned by optometrists or the fine print on contact lens packaging about not showering or swimming while wearing contacts.
The Contact Lens Society of America said via email that “contact lenses are medical devices, and care and hygiene instructions — including avoiding contact with water while swimming, showering, or sleeping — are an important part of routine contact lens care.” The CLSA is a network of members from the eye care field and the contact lens manufacturing and services industry.
The society added that it “encourages clear, ongoing communication by providers and active engagement by patients — including asking questions, reviewing written materials, and talking through any uncertainties about safe lens use.”
In addition to pain, light sensitivity and obscured vision, acanthamoeba keratitis can also cause redness, dryness, excessive tears and a sensation of a foreign body in the eye.
Lack of awareness of the disease and some acanthamoeba keratitis symptoms mimicking those of other corneal infections make it easy for optometrists to misdiagnose patients, Barney said. The most common misdiagnosis is herpes simplex keratitis, a leading cause of infection-induced blindness.
In the earliest stages, acanthamoeba keratitis can even seem like pink eye, which Sanchez said was her optometrist’s diagnosis when she saw him about a month after she started having symptoms.
Accordingly, the treatments misprescribed can be ineffective at best and harmful at worst, all while the parasite further destroys the cornea. Drops for viral pink eye blurred Sanchez’s vision, she said. A second optometrist thought Sanchez had bacterial pink eye; antibacterial drops worked for a bit before she completely lost vision in the infected eye.
Grace Jamison, a 20-year-old woman in the western United States, had a similar experience. Jamison developed acanthamoeba keratitis in both eyes after wearing her contacts while showering in the Dominican Republic in May. When she arrived back home several weeks later, her optometrist misdiagnosed her and prescribed steroid drops. After just another week, Jamison was blind — and she remained that way for about two months before she began proper treatment.
“A lot of the time, we don’t realize how good life is or how there’s so many things that can go wrong,” Jamison said. “It’s so sad that we don’t appreciate what we have when we do have it. When I was completely blind in both of my eyes, I regretted not taking advantage of how I could see before.
“I regretted not being on screens less, just looking at how beautiful outside is, or looking at people that I know and love.”
The cause of Jamison’s clouded vision is damage from an inflammatory response to the pathogen.
“There’s times when I get really sad and I wish that my right eye didn’t look like it didn’t have a pupil,” Jamison said. “And occasionally I get people in public that are like, ‘What’s going on with your eye?’”
Want to reduce your chances of getting acanthamoeba keratitis? When cleaning and storing contacts, always use store-bought or prescription contact solution instead of water, experts said. The solution in your contacts case should also be changed every day.
Washing and drying your hands before applying contacts is important for preventing eye infections from various sources. Never wear your lenses while asleep, either, since that can cause dryness, irritation, abrasions and entrapment of germs that can lead to serious infections. Using daily disposable contacts instead of monthlies can also lower risk for infections.
If doing water-based activities without wearing contact lenses isn’t safe for you, you can try glasses or prescription goggles. But the concern may also be a good reason to discuss vision correction surgery with your doctor, said Dr. Ashley Brissette, an ophthalmologist at Kelly Vision, a LASIK and cataract surgery center in New York City.
Such procedures include Smile, PRK (photorefractive keratectomy) or LASIK — all laser-based surgeries — and EVO ICL, which stands for “evolution implantable collamer lens,” Brissette said. Each of those surgeries has its pros and cons, she added, and what works for one person may not for another, depending on one’s eye shape, health and prescription. Brissette underwent LASIK and found it “life-changing,” she said.
Accurately diagnosing acanthamoeba keratitis begins with taking a careful history of a patient’s recent contact-wearing and lens care habits, Barney said.
There are a few tests, including a corneal razor scraping, swabbing or biopsy that can be processed in a lab via culturing or a polymerase chain reaction (PCR) test, which diagnose based on the organism’s genetic information, experts said. A confocal microscopy, an advanced imaging technique, allows professionals to see the amoeba in the cornea once it encapsulates itself as a cyst, Barney said. In this form, the organism can lie dormant for months to years in response to harsh environments, including those created by the human host’s immune response or medications meant to kill the parasite.
However, these tests, especially the more advanced ones, aren’t readily available everywhere, and neither are the specialists who administer them, he added. Testing is usually found in university settings or conducted by cornea specialists, and there aren’t many of them.
Not getting accurately diagnosed until seeing a cornea specialist, as in Sanchez’s and Jamison’s cases, is a common experience for patients with acanthamoeba keratitis.
If you’re experiencing any concerning symptoms and know you were recently engaging in a high-risk behavior, see a cornea specialist as soon as possible, sources recommended.
“Early recognition can really help to improve your outcomes,” Brissette said.
Trying to kill an acanthamoeba while protecting the eye is complicated.
The first-line treatments are anti-amoebic eye drops such as chlorhexidine, propamidine isethionate, hexamidine or PHMB, which is unlicensed in some countries, including the United States, Lorenzo-Morales said. Some of these drops, especially the chlorhexidine, can cause intense pain due to toxic effects on the cornea, adding to the agony the parasite is already causing — hence a need for new treatments, Lorenzo-Morales added.
“The drops are so, so painful but it’s not deep pain — it feels more surface level, like extremely raw and dry,” said Hannah, a 26-year-old woman who has had acanthamoeba keratitis since September 2024. Hannah asked that her last name not be used due to privacy concerns.
However, the treatment wasn’t as bad as the pain from the infection itself, which gave Hannah “the worst migraine of my life,” she said. “I would be on the floor in my bathroom in fetal position, crying and throwing up.”
Patients are sometimes prescribed two types of medication simultaneously and must apply several drops of each one every half hour or hour, for days to weeks before they can start to reduce dosage and frequency.
“It’s been horrible,” Jamison said of her treatment over the past four months. “You have to get (the eye drops) specially compounded, and they have to be refrigerated at all times because there are no preservatives in them.”
Hannah keeps a mini fridge by her bed, and an insulated travel bag on hand, to minimize how much treatment interferes with her sleep, running errands or socializing.
Sometimes when a patient’s eye has scarring on — or thinning or perforation of — the cornea, a cornea transplant is necessary, said Brissette, who is also a spokesperson for the American Academy of Ophthalmology.
“The scarring in my right eye is right in the center of my vision and covers my whole pupil,” Jamison said. She said her doctor was looking into securing a scleral lens, which is made of breathable plastic: “That’s to hopefully shave down the scarring to make it more smooth, which could help improve my vision.”
Jamison still has to endure about a year of treatment, and her vision has improved slightly. From her right eye, she mostly just sees white, or shapes or lights when she squints. She has to get her face really close to whatever she’s reading, and she can’t drive.
But her vision will never be better than 20/40 unless she gets a cornea transplant, she added. That isn’t an immediate solution — a bit of the patient’s own cornea is still required for a transplant. And there is a risk of the parasites becoming dormant for years before reactivating and destroying a new cornea. So, doctors must first give a patient’s eye at least several months without treatment to ensure sufficient healing.
Sanchez had a cornea transplant in October, about 2 ½ years after contracting acanthamoeba keratitis. She then developed a cataract that was removed this October. “So far, 20/20 vision is where I’m at right now,” she said. “I feel very, very blessed that this is my outcome.”
Hannah has largely recovered but needs to continue treatment for a couple of months, and her vision in one eye is much blurrier than that of the other, she said.
For people being treated for acanthamoeba keratitis, Sanchez’s “biggest advice is that they trust their doctors and to be patient and not compare their journey with everybody else’s journey.”
“I was angry at the fact that my doctors didn’t want to go the fast route and do the transplant sooner, do the cataract surgery sooner,” Sanchez said. “But I’m glad that I trusted them, because had I not, I don’t think that 20/20 vision would have been my outcome, even though it came to me three years later.”
Hannah and Sanchez also recommended joining an online support group, which can be helpful emotionally but also practically. Members of their groups have suggested doctors to help expedite diagnosis and treatment plans or advised ways to cope with the effects of the condition.
“I know it’s tough, but hang in there. It’s going to get better,” Hannah said, though what’s “better” varies for every patient.
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