and ophthalmologists we are experts in the eyecare field, however, we actually haven’t experienced most of the eye conditions we diagnose and treat on a regular basis. Because of this, we can learn so much from our patients every day. Even conditions that are commonly seen, like cataracts
, can be a completely different experience from the patient perspective.
Understanding our patients’ experiences can make us better practitioners and enhance care for future patients. This patient perspective series will seek to turn the tables and give our patients the opportunity to be the experts in their diseases and ocular conditions to enhance the eyecare we provide.
As eyecare providers, we have all heard of acanthamoeba keratitis (AK), but likely many of us—unless practicing in an advanced corneal setting
—have not seen this condition in our chairs firsthand.
Acanthamoeba keratitis: An overview
is a rare but often devastating ocular condition that can lead to severe vision impairment, corneal transplantation, and even enucleation. It is caused by a free living amoeba that is typically found in soil and water, including tap water.
These amoebas are ubiquitous. In fact, serologic studies
have confirmed that 90-100%
of people without
prior AK infection actually have antibodies to Acanthamoeba, which shows that while the organism is very common, infection from it is very rare.
The main risk factor for AK is contact lens wear
. While there are 33 million contact lens wearers in the United States, there are only 33 cases
of AK per one million contact lens wearers. AK presents initially with a high degree of pain, often out of proportion to the clinical signs observed. Many times, this condition is misdiagnosed as herpes simplex keratitis.
It seems infection from Acanthamoeba occurs due to a myriad of factors, including the corneal microbiome. Acanthamoeba exist in two states: Trophozoite and cyst stage. In the cyst stage, they can live in very harsh conditions ranging from hot springs to underneath ice.
Our innate immune response can fight the infection, but once the amoebas have breached the corneal epithelium, it is difficult for the immune system to fight these parasites due to the fact the cornea is an immune-privileged tissue. Cysts can remain in a dormant state on corneal tissue for close to 3 years
making recurrent infection possible.
Clinical note: Always be wary that you may have misdiagnosed AK if what you are treating as HSK is not responsive to standard treatment.
Interview with Juliette Vila Sinclair Spence
In this interview, Juliette Vila Sinclair Spence, an “AK Warrior” and true AK expert who contracted Acanthamoeba keratitis in 2016, shares the details of her long and arduous journey to diagnosis and finally treatment. She has devoted much of her time to help others learn more about this disease and has became an advocate for patients, families, and providers by creating the Acanthamoeba Keratitis (AK) Eye Foundation
Did you know of Acanthamoeba keratitis before your experience with it?
I had never heard about Acanthamoeba keratitis nor its risks, despite having worn contact lenses
for more than 35 years. I was never taught that contact lenses and water don’t mix, meaning do not to shower, swim, do water sports, wash or store them with water, nor handle them with wet hands. I’m not the only one who didn’t know this; in fact, 95% of AK Warriors
are contact lens wearers. Only 5% of those who have experienced AK are not contact lens users.
Sadly, numbers are increasing worldwide. For example, in the Netherlands, where I live, the number of cases increased from 16 in 2009 to 49 in 2015
. This resulted in an estimated incidence of 1 in 21,000 for soft contact lens wearers in 2015.
How did you contract AK?
How long before symptoms of Acanthamoeba keratitis appeared?
Vila: Symptoms can manifest within hours, days, or weeks. For me, once I got out of the swimming pool, I felt like my contact lens was dirty or something was on it, so I washed it, but that was not enough.
The day after, I felt like something was in my eye and the feeling would not go away, so I removed my monthly contact lenses and wore my glasses instead. I dismissed the symptoms of “unhappy eyes” and light sensitivity due to fatigue as the result of being a tired mum of two young boys. What I learned: Contact lens users should get their eyes checked whenever they feel something is different with their contact lenses and/or eyes.
For the next 6 months I only wore glasses, as each time I tried to wear contact lenses my eye felt like there was something in it. I continued to have a bit of light sensitivity and the vision quality had decreased. My optometrist let me try a variety of different contact lens brands
, but my symptoms would not get better. He figured it was the contacts and so he did not see the need to look further. At the end of February 2017, the nightmare really started and never stopped.
What symptoms did you experience? What are other common symptoms?
In my case it started as an eye irritation, redness, feeling something in my eye (like an eyelash or a grain of sand), an ache in and around the eye, tearing and mild light sensitivity. As the hours went by, it turned into excruciating pain, non-stop tearing, extreme light sensitivity and decrease of vision
For most AK Warriors, these symptoms are common:
- Foreign body sensation - feeling like something is in the eye
- Inability to wear contact lens
- Irritation or grittiness
- Red eye
- Watery eyes
- Mild to extreme light sensitivity
- Aching to excruciating eye pain
- Blurred vision
- Partial or total vision loss
Were you diagnosed quickly? What did it take for you to receive the correct diagnosis?
Vila: On the first of March 2017, I went to my general practitioner who after making a quick test (fluorescent eye test) could detect damage in my cornea, so they sent me to the ophthalmologist at the hospital the same day. The ophthalmologist misdiagnosed me with a bacterial infection and gave me Trafloxal (fluoroquinolone eye drop). The doctor only asked me if I was a contact lens user but did not ask any further questions.
I returned on the 4th of March to the emergency room
as the pain was escalating. The ophthalmologist on duty decided to change the medication to hydrocortisone/oxytetracycline and asked me to visit her every 2 days to follow my eye. During that period, we did three corneal scrapings, added atropine as well as analyzing my contact lens casing. But still, it was 17 days after the initial ophthalmology visit (7 months after swimming with my contacts in Italy) that I was correctly diagnosed with Acanthamoeba keratitis. This diagnosis was ultimately made with a confocal laser scanning microscope (CLSM), which is the gold standard for diagnosing AK, as it is painless and can provide feedback in situ, allowing treatment to begin immediately.
Diagnosis of Acanthamoeba keratitis
- Symptoms (intense pain) out of proportion to clinical signs
- Ring-shaped stromal infiltrate
- No improvement with standard antiviral, antibacterial, or antifungal therapies
Diagnosis confirmed by:
- Culture on non-nutrient agar plated with E. coli
- Confocal microscopy
AK as a learning opportunity for eyecare providers
Vila: The ophthalmologist who diagnosed me with a bacterial infection did apologize to me months later for the misdiagnosis. He explained that it was a learning opportunity for him to always go the extra mile when it comes to contact lens wearers. The correct diagnosis for AK Warriors can take between days, weeks, and months to even a year or more.
The fact that Acanthamoeba keratitis is cited as a rare disease, makes it more challenging as clinicians do not often have it on their radar and may think a contact lens-related red eye is a more common and benign condition. When red eye does not improve with initial treatment, clinicians should beware and investigate further or make the appropriate referrals if the patient is not improving.
What treatment did you receive? What other treatments do you know of?
Vila: After being correctly diagnosed with Acanthamoeba keratitis—17 days since the first severe symptom—I was given propamidine isethionate, chlorhexidine (the AK pool cleaners as we call them), every hour around the clock for the first 4 days and then every hour while awake. I was also given itraconazol (anti-fungal); atropine (to help with the photophobia); and for pain management I got diclofenac (to reduce inflammation/pain), tramadol, and paracetamol.
Because the treatment was not working and my eye, the pain and my mental state were getting worse, the doctors decided to conduct an emergency therapeutic corneal transplant—28 day after the first symptom.
After the corneal transplant
, I was on autologous serum drops for 30 days, as my corneal epithelium would not close within the normal timeline which put me at risk of losing my new cornea. I was on propamidine isethionate for 3 months, chlorhexidine for 14 months to make sure all cysts were eradicated and pregabalin (Lyrica) for the trigeminal nerve pain for the rest of my life. Today, I am still honoring the cornea’s donor after 5 years.
Image 1 of Juliette’s eye while infected with AK and post-corneal transplant. Images used with permission.
Image 1: Shared with patient permission.
What I have seen with other AK Warriors through my work with the Acanthamoeba keratitis (AK) Eye Foundation, is that no one has the exact same approach, it is always a puzzle between the knowledge of the doctor that is treating the AK Warrior, the condition of the eye, the stage of the infection and the Acanthamoeba strain.
Some people have unilateral disease, others bilateral Acanthamoeba keratitis. Some have Acanthamoeba scleritis which is a rare and painful complication of Acanthamoeba keratitis, affecting 10–18% of patients.1-3
Having said that, what is common is to get an antifungal medication, an antibacterial medication, and an antiviral medication together with their AK treatment.
Below is an example of the different treatments and/or procedures provided to AK Warriors worldwide:
Treatments for Acanthamoeba keratitis
- Blood serum drops (autologous serum)
- Plasma serum drops
- Polyhexamethylene biguanide (broad-spectrum antimicrobial)
- Chlorhexidine (antimicrobial)
- Propamidine isethionate (antiseptic and disinfectant)
- Voriconazole (antifungal)
- Milfetosine (antiparasitic)
- Voltaren (NSAID)
- Pregabaline (Lyrica)
- Miconazole nitrate (antifungal)
- Paracetamol (acetaminophen)
- Valacyclovir (antiviral)
- Streptomyces tenebrarius (tobramycin)
- Omeprazole (PPI)
- Nitrofurantoin (antibiotic)
- Trafoxal (fluoroquinolone eye drop)
- PACK- CXL (UVA/Riboflavin corneal cross-linking)
- Phototherapeutic keratectomy (PTK)
- Penetrating Keratoplasty (PK) - full corneal transplant
- Deep anterior lamellar keratoplasty (DALK) - partial corneal transplant
- K-pro (Keratoprothesis - “artificial” corneal transplant)
- Debridement of the cornea
- Amniotic membrane graft
- SLET (simple limbal epithelial transplantation)
- Micro-pulse laser procedure
- Ahmed glaucoma valve
- Laser trabeculoplasty (Laser for glaucoma)
What lasting effects from Acanthamoeba keratitis do you still experience?
Vila: In my case a few, but I’d rather these than the excruciating pain I was in previously. I am grateful to still have my eye and my vision albeit imperfect.
Let me start with nonstop trigeminal nerve pain which makes me take a high dose antiepileptic medication daily to reduce the pain (but it never goes away). If by any chance I forget a dose for a couple of days my pain increases rapidly. High astigmatism and a small cataract
on the AK eye so uneven prescription and without glasses I cannot see from that eye. An operation to remove the cataract is not possible for now as it is not large enough for the insurance to cover the surgery.
Light sensitivity makes me wear a visor and sunglasses
when I go out of the house or in large office buildings/malls as I need to block the light that is coming from the top as well as straight ahead of me (on both sunny and rainy days). Not to mention when I am tired or stressed my AK eye is the first one to let me know by really being more light sensitive, painful and even appears smaller.
to which I need to use refreshing drops every day. PTSD due to excruciating pain and experience I went through as well as being always on guard not to get water in my eyes. And finally tired as my brain is always on guard as well as doing extra focus/concentration on using my non-AK eye so I can move around “normally”.
For AK Warriors, each journey is unique, and some have more aftermath than others.
Common symptoms and lasting effects from AK include:
- Trigeminal nerve pain
- Dry eye
- Severe eye inflammation
- Limbal stem cell damage
- Extreme high or extreme low eye pressure
- Retinal detachment
- Liver problems due to medication
- Mouth/tooth problems due to steroid use
- Optic nerve damage
- Retrocorneal membrane (retained Decemet’s after PKP)
- Corneal perforation
- Loss of vision
- Loss of eye
- Iris irregularity (atrophy, dyscoria, corectopia, or synechiae)
- Charles Bonnet Syndrome
- Neovascularization (new blood vessel growth)
What would you like other patients as well as eye doctors to know about this condition from your experience?
Vila: Acanthamoeba keratitis might be difficult to pronounce, a rare eye disease (that for many implies it will not occur to me or is not common) but once you experience or have a patient with it, you will never forget it and wish you knew what we AK Warriors know.
We should consider Acanthamoeba keratitis in all contact lens wearers and in any case of corneal trauma with exposure to soil or contaminated water.4
Final thought from an AK Warrior
For contact lens users
Educate yourself – it is your right – on what you can and cannot do with your contact lenses from your trusted eye doctor. Always have your routine eye exams and use official products. Contact lenses are medical devices so extra care is necessary to ensure you can enjoy your contact lenses and have happy, healthy eyes.
IMPORTANT: If you feel something is not right, do not wait, take off your contact lens, seek professional help, and please give detailed history to your doctor so they have a complete picture. And remember:
- Never let water mix with your contact lenses
- Never shower or bathe with your contact lenses
- Never swim with your contact lenses
- Never touch your contact lenses with wet hands
- Never wash your contact lenses with water
- Never store your contact lenses in water
- Never go to the sauna with your contact lenses
For AK Warriors
There is a community that understands your journey. We invite you, your family, and friends to join the support group
so we can walk with you. No one should go through this journey alone. The support group helps you get through the horrible and unpredictable journey.
For optometrists and ophthalmologists
Educate your patients about the do’s and don’ts regarding contact lenses especially when it comes to water exposure. Provide clear information for contact lens wearers about how seriously a mistake in the handling of contacts or an unfortunate situation can affect your eyesight. Take each visit as an opportunity to offer a friendly reminder.
- Educate yourself on how to recognize AK, know the key questions to ask and how to differentiate AK from other similar look-alike infections such as Herpes simplex keratitis, bacterial keratitis, and fungal keratitis. Remember: pain out of proportion to signs and/or a ring infiltrate are key factors to diagnosis! Nonresponse to standard antibacterial or antiviral treatments is another potential sign that you may be dealing with AK.
- Rule out AK first! If there is a contact lens user experiencing itchy, watery eyes, pain, sensitivity to light, redness, and/or blurred vision, ask more questions: has the patient been in contact with water, gardening or washing their eyes with water (even non-contact lens users)? Always use steroids with caution in contact lens wearers. Do not start a patient on steroids without ruling out AK, due to the potential risk of promoting encystment and increasing the number of trophozoites.5 In an informal survey of 127 ‘AK Warriors’, of 80% who were misdiagnosed, more than half were diagnosed with herpes simplex keratitis and given steroids (even though this is an inappropriate treatment even for HSV).6
- Please carefully look for signs and pay attention to the symptoms. If you are uncertain of the diagnosis, please refer to someone with more experience in treating AK. Remember: time is of the essence when diagnosing and treating AK.
- Listen to your patient, the pain is excruciating! One of the main signs of AK is the pain is out of proportion to what you will see behind the slit lamp when examining the patient’s eye. Patients with AK will often also need pain specialists involved in their care. Counselors and information about support groups is also incredibly useful even from an early stage.
- Often, we find that a therapeutic corneal transplant has more impact in the early battle than the long-term use of non-stop toxic drops necessary for medical treatment.
- When an AK Warrior comes to you and says they had enough, and they just want the eye out because they are tired of fighting, listen to them. It is not just a fleeting comment. Don’t use the eye of an AK Warrior as a lab experiment to try different alternatives. There are many AK warriors that spend years trying to save the eye and the impact on their life and mental health is devastating.
As you can see from Juliette’s candid story, Acanthamoeba keratitis is a devastating condition with a variety of complex and persistent symptoms. While it may not be something we see often, it is vitally important for our patients that we educate them on proper contact lens hygiene and rule out AK in any red eyes especially with a relevant history. For more information on AK please check out the AK Eye Foundation
, AK info page
and AK Support Group
. Be sure to stay tuned to the next installment of our patient perspectives series.
You can connect more with Juliette and other AK Warriors in their Facebook group
and can hear more about Juliette’s story here
- Mannis MJ, Tamaru R, Roth AM, Burns M, Thirkill C. Acanthamoeba sclerokeratitis. Determining diagnostic criteria. Arch Ophthalmol. 1986 Sep;104(9):1313–7.
- Lee GA, Gray TB, Dart JK, Pavesio CE, Ficker LA, Larkin DF, et al. Acanthamoeba sclerokeratitis: treatment with systemic immunosuppression. Ophthalmology. 2002 Jun;109(6):1178–82.
- Iovieno A, Gore DM, Carnt N, Dart JK. Acanthamoeba sclerokeratitis: epidemiology, clinical features, and treatment outcomes. Ophthalmology. 2014 Dec;121(12):2340–7.
- Lorenzo-Morales J, Khan NA, Walochnik J. An update on Acanthamoeba keratitis: diagnosis, pathogenesis and treatment. Parasite. 2015;22:10.
- Szentmary N, Daas L, Shi L, Laurik KL, Lepper S, Milioti G, Seitz B. Acanthamoeba keratitis - Clinical signs, differential diagnosis and treatment. J Curr Ophthalmol. 2019 Mar;31(1):16-23.
- Acanthamoeba Keratitis Support Group [internet]. Netherlands. c2021- 2022 [cited 2022 Jan 22]. Available from https://www.facebook.com/groups/acanthamoebakeratitissupportgroup