Acanthamoeba Keratitis (AK) is a severe eye infection that can cause excruciating pain and damage to the cornea, often resulting in vision loss or even blindness. It is caused by a free-living amoeba that is commonly found in bodies of water, tap water and soil.

One of the most concerning aspects of AK is the potential for severe vision loss. In fact, approximately 41% of AK cases eventually require a corneal surgical procedure or even become blind. Most cases are unilateral (affecting one eye) while there is 4% to 11% for bilateral (affecting both eyes)There is a high enucleation rate of 6%. So some AK patients choose to remove their eye. It is important for individuals to take preventative measures to avoid contracting AK.

Image source: The estimated annual incidence of Acanthamoeba keratitis by regions (as defined by the UN). The figure used with permission from co-author Xu. Source: Yuheng Zhang, Xizhan Xu, Zhenyu Wei, Kai Cao, Zijun Zhang, Qingfeng Liang, The global epidemiology and clinical diagnosis of Acanthamoeba keratitis

The life cycle of Acanthamoeba is typically divided into two stages:

TROPHOZOITE STAGE

During the trophozoite stage, the amoebas are active and mobile, feeding on bacteria and other small organisms in its environment. This is when you might experience a lot of pain, light sensitivity and/or sometimes a deterioration in vision.

CYST STAGE

In the cyst stage, the amoebas are passive as they have formed protective double-walled cells that allows them to survive in harsh environments with low nutrients or high toxicity. This can happen due to changes in pH levels or exposure to therapeutic agents.

Images 4 – Cyst –  supplied and used with permission from Dr. Christopher A. Rice (Purdue University). Preparation of cells and Scanning Electron Microscopy (SEM) imaging of amoeba was performed by A. Cassiopeia “Cassie” Russell (University of Georgia) on Dr. Peter Bush’s Field Emission Scanning Electron Microscope (FESEM) with Oxford Energy-dispersive X-ray Spectrometer (EDS) – Hitachi SU70 (University at Buffalo)

Image 1: Scanning electron micrograph (SEM) of two Acanthamoeba trophozoites approaching an indent in a contact lens, © Fiona L Henriquez, Adam Hammerschmid. University of the West of Scotland (UWS), U.K

You may experience:

Eye pain from mild to excruciating
Red eye
Foreign body sensation
Blurred vision or complete loss of vision.
Sensitivity to light from mild to extremely high
Excessive tear production
Irritation or grittiness
Headache
Inability to wear contact lenses

These symptoms can have a substantial impact on a person’s quality of life.

If you suspect that you might have AK, it is important to seek medical attention right away. Here are some steps you can take:

STOP wearing contact lenses.
CONSULT an eye doctor as soon as possible.
LET THEM KNOW if you are a contact lens user and have been in contact with water.
TAKE the contact lenses, casing, and solution with you for possible analysis.
ADVOCATE, if available, for an early confocal scan to confirm the diagnosis. Time is of the essence!

Remember, early diagnosis and treatment are key to preventing serious complications from AK.

Contact lens wearers are especially susceptible to AK because contact lenses can cause small defects on the cornea or trap the parasite between the contact lens and the eye. Therefore, it is crucial to never let water touch your contact lenses. In addition, it is important to follow proper contact lens hygiene and cleaning procedures to further reduce the risk of AK infection.

Water and Contact Lenses don’t mix

Never use water to store or rinse your contact lenses
Never sleep wearing your contact lenses
Never shower wearing your contact lenses
Never swim wearing your contact lenses

Source: Delayed diagnoses of Acanthamoeba keratitis at a tertiary care medical centre

Unfortunately when it comes to properly diagnose AK, statistics show that around 69% of AK Warriors worldwide are being misdiagnosed amongst others herpes, bacterial, viral, or fungal pathogens. Even more concerning is that over 38% of AK cases are misdiagnosed as herpes simplex, this can lead to the administration of corticoids and steroids, worsening the infection and the situation, and 20% as bacterial infection.

While there may be similarities in symptoms with other infections, the treatments are vastly different. It is crucial to get the correct diagnosis for AK quickly. Because of misdiagnoses the recognition of AK often takes days, weeks, months, or even over a year, during which time the amoeba can continue to multiply or hide deeper in the cornea.

In the second phase these eye drops are used during waking hours. The duration of this whole process depends on the severity of the infection, the availability of the drugs and the experience of the specialist. This can take from six months up to one year or even longer. However, in some cases medication may be stopped to see how the eye reacts before restarting treatment in case of a relapse.

Once the amoeba has been eradicated, the specialist’s next priority is to help restore vision. This may involve procedures such as cataract surgery or corneal transplantation. The outcome of treatment varies greatly, ranging from clear vision, to vision loss or eye removal.

The journey is characterized by many ups and downs, with the intense drop regime, excruciating pain, and many eye appointments, leaving little space for daily life. AK affects not only the eye, but also the mental and emotional health of the patient.