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Suspect of AK on Contact Lens Users

Make it a norm to always consider the possibility of AK in all contact lens wearers with any case of corneal trauma with exposure to soil or any kind of water.

Every day counts! The sooner you confirm AK the better the outcome for the AK patient.

Be aware that contact lens wearers typically seek medical help late, because they are used to minor irritations in the eye.

If you are not an expert in this rare disease, reach out to someone who is!

AK is not just a routine eye infection; it is much more than that! It’s excruciatingly painful and debilitating. It also affects the body and mind. The risk of blindness or enucleation is high.

What is Acanthamoeba Keratitis?

Acanthamoeba keratitis (AK), is a devastating, extremely painful eye infection that affects the cornea (the window of the eye). It is mainly found in association with contact lens wearers with specific behaviours, putting these people more at risk – although there are cases of this disease in non-contact lens users. AK can lead to severe vision loss with around 50% of patients needing corneal transplantation or becoming blind, and for around 5-10% of patients can also result in enucleation (removal) of the eye. AK is frequently misdiagnosed, and the associated pain can be widely underestimated by various clinicians.

Read more about Acanthamoeba Keratitis

Easily misdiagnosed – Don’t start on steroids




Herpes Simplex Virus

80% of AK patients are misdiagnosed with bacterial, viral, or fungal infection. Half of them were diagnosed with HSV keratitis and given steroids. Source (Acanthamoeba Keratitis Support Group [internet]. Netherlands. c2021-2022 [cited 2022 Jan 22].

Acanthamoeba Keratitis is easily misdiagnosed.

If patients are experiencing itchy, watery eyes, pain, sensitivity to light, redness, and/or blurred vision, check if their contact lenses have been exposed to water.

In the early-stage AK can easily be confused with Herpes simplex keratitis, while in the advanced stage, the infection resembles the clinical picture of a fungal keratitis or a corneal ulcer


Rule out AK when Herpes Simplex Virus (HSV) keratitis is suspected.

Do not start with steroids before confirming AK is not present – this is due to the potential risk of promoting encystment, increasing the number of trophozoites and making the situation worse through steroids.

From first symptoms to correct diagnosis it can take between days, weeks, months, or even more – depending on how quickly the patient can reach a doctor with expertise while the amoeba is multiplying.

How to diagnose Acanthamoeba Keratitis?

The sooner you as a medical practitioner seek expert advice and/or refer the patient to a corneal and/or infectious disease specialist with experience of AK, the better service, and chances of an improved outcome you are providing to your patient.

The care of the patient should not be focused on puzzling with their eye and trying to guess which is the right approach. The care of a patient should be focused on providing the best chances to fight!

There are hospitals with experience in AK treatment, according to AK Warriors. 

The first and most important step when it comes to diagnosis is to always suspect AK – especially in a contact lens wearer, who has been in contact with water and/or recently has been diagnosed with another type of keratitis like herpes simplex virus and is not responding to therapy.

Each AK patient has their own journey. For some it might start relatively mild, for others it is extreme from the beginning.

Key characteristic signs

  • Symptoms out of proportion to clinical signs
  • Extreme pain
  • Extreme photophobia
  • No improvement with standard antiviral, antibacterial, or antifungal therapies
  • Can present as a ring-shaped stromal infiltrate in later disease.

    When confirming the diagnosis, there is no standard approach, and all depends on the clinician and what is available.


    Clinical picture of the eye and the patient. 



    PCR (Polymerase Chain Reaction) of corneal scrapings
    may give a result within 60 min.

    In vitro culture
    Escherichia coli (E. coli), give results within 3 weeks 

    IIVCM (n vivo cornea confocal microscope imaging)
    is a non-invasive imaging modality that can rapidly and accurately diagnose AK and needs to be carried out by an experienced hand and can give results immediately.


    Is very important! Ask the history over the last 1-2 months with their contact lenses.

    Here some examples of questions you can ask:

    • Have you been swimming, doing any type of water sport or visited any pool while wearing your contact lenses?
    • Did you shower wearing contact lenses?
    • Did you wash your hands before putting the contact lenses in the eyes or before taking them out again?
    • Did you dry your hands thoroughly with dry cloth or tissue paper before touching your contact lenses? Or might they have been still a bit wet?
    • Do you clean your contact lenses regularly, have you ever rinsed your contact lenses with water?
    • Did you store your contact lenses in old solution or water?
    • Did you wear your contact lenses for longer than 12 hours or have you kept them in your eyes while sleeping?

    These are some of the most important questions and does not take long for a doctor to ask. Always suspect AK in contact lens patients until proven otherwise.

    How to treat Acanthamoeba Keratitis?

    Generally, the first aim is to eradicate the amoeba. This takes time (3-18+ months). Regaining vision is a lower priority. The focus should be on eradicating the amoeba.

    With AK there is a lot of damage to the cornea as it is literally being eaten. The amoeba can migrate deep into the corneal tissue making it even more difficult to treat, especially if it encysts.

    There is no official standardized protocol treatment available for AK that targets the trophozoite stage and the cyst stage. New drugs and therapies are being tested or in development. Current AK treatment consists of topical antimicrobial agents, such as biguanides, PHMB, Chlorhexidine used in combination with aromatic diamidines propamidine isethionate, dibromopropamidine, hexamidine, desomedine, and neomycin.

    In severe cases we see that AK Warriors are also being given oral medication like Milfetosine or Voriconazole.

    Unfortunately, propamidine and hexamidine may not be available in all countries; making it hard for the AK Warrior to start the needed treatment.

    There has been a 15-year-old clinical trial on polyhexanide to become the first license treatment for Acanthamoeba Keratitis. Nowadays there is an Early Access Program for Polyhexanide for certain countries.

    The treatment normally tends to go by the hour for the first days 24/7, then every waking hour for several weeks and, if there’s improvement then reducing the drops very slowly while monitoring closely how the eye is responding.

    A potential relapse is the main worry of the AK Warrior. We see a lot of AK Warriors where their medication has been stopped or reduced too quickly and sadly a relapse occurs.

    Sometimes a therapeutic partial or full thickness cornea transplantation is performed to help debulk the eye from the parasite and give a better chance of treating the infection.

    Also keep in mind that each case is unique … what works for one patient, might not for another.

    What does AK mean for your patient?

    As an AK patient we have no energy, our eye can´t stop tearing, our sinus, head and jaw is hurting, our body is trying to fight the infection, the inflammation, coping with the excruciating pain, deprivation of sleep and our mind is spinning, we hide in a completely dark room, depressed, isolated from the world for weeks, feeling we will never make it out of it or missing so many plans, anxious and worried about our vision, we can’t enjoy sunlight for many months. Many of us end up with medical PTSD, afraid of a relapse, water, traumatized by the intensity of the treatments and procedures. And for many there are aftermaths like glaucoma, dry eyes, no depth perception, not being able to drive in the night, disfigured appearance, vision loss, trigeminal nerve pain, loss of eye as an organ and more.

    How can you support your patient?

    Let them know they are not alone on this journey, and you have their back.

    Make time for them, ask direct questions about how they are doing and how else you can help them. (Example: answering their questions, pain management, ask whether they have help for daily life, psychological support, referral to an expert, what to expect, possible aftermath (link), what is the focus first and give some perspective.

    Refer them to the Acanthamoeba Keratitis Eye Foundation, where they can find good information about AK and access to a support group.


    In our support group we welcome not only the AK Warriors, family, friends, but also eye professionals, opticians, optometrist, ophthalmologist, corneal specialist, researchers, psychological professionals and any others that want to understand the impact of Acanthamoeba Keratitis and learn from the patient’s perspective.

    You can join by clicking on the button “Join Support Group” or scanning the QR code.


    The pain that AK Warriors goes through can only be understood by other AK Warriors. It’s so debilitating and excruciating, that if they were to give it a number it would be a 10 out of 10 – and they are not exaggerating.

    You need to refer them to a pain specialist for pain management from the first day of diagnosis. Ordinary over-the-counter pain killers are usually far from adequate.

    During AK a patient experiences different types of pains: burning pain, toxicity pain, stabbing pain, headaches, sinus, tooth pain and trigeminal nerve pain.


    When a patient is going through AK, it’s not just having an eye infection: there is the fear of not knowing what will happen; the loss of vision; the nonstop eye dropping interrupting every task, meal, talk, thought; the lack of sleep; the excruciating pain; the isolation due to light sensitivity; hiding in the dark longing for sunshine; the life standing still; the fear of water; the trauma due to the way they are mistreated, not being heard or the type of treatments they are put through.

    Offer them the opportunity to refer them to a mental counsellor, as well as encourage them to join the Support Group.