Condition

Acanthamoeba Keratitis

Also known as Acanthamoeba Eye Infection, Amoebic Keratitis, Contact Lens Amoeba Infection, Acanthamoeba Corneal Infection, Water-Related Keratitis

Updated May 16, 2026For educational purposes only. Not a substitute for medical advice. See our terms.

Bottom Line

Acanthamoeba keratitis is a rare but serious cornea infection linked to water and contact lenses. Pain can be severe, and early care matters.

Acanthamoeba keratitis is an infection of the cornea caused by amoebae found in water, soil, and air. It is uncommon, but it can cause severe pain, scarring, and vision loss 1.

Most cases occur in contact lens wearers. Risk rises when lenses or lens cases touch tap water, showers, pools, hot tubs, or homemade solutions 2.

Diagnosis is often delayed because it can look like herpes or other keratitis. Treatment can require months of anti-amoeba drops and close cornea care 3.

Symptoms

Acanthamoeba keratitis may start like a routine contact lens problem.

  • Eye pain. Pain can be strong and hard to ignore.
  • Light sensitivity. Bright light may hurt.
  • Redness and tearing. The eye may water a lot.
  • Blurred vision. Vision can worsen as the cornea swells or scars.
  • Slow course. Symptoms may not improve with antibiotic or herpes treatment.

Acanthamoeba keratitis is often mistaken for other cornea infections early on 3.

Treatment

Treatment is usually managed by a cornea specialist.

  • Anti-amoeba drops. These often include biguanide medicines.
  • Frequent dosing. Drops may be very frequent at first.
  • Pain control. Pain may need prescription support.
  • No contact lenses. Lenses stay out until the doctor clears them.
  • Surgery. Severe scarring or thinning may need a cornea transplant.

Reviews of Acanthamoeba keratitis stress early diagnosis and long treatment because cysts resist many medicines 1.

Prevention

Water and contact lenses do not mix.

  • Do not shower, swim, or use a hot tub in contact lenses.
  • Do not rinse lenses or cases with tap water.
  • Use fresh disinfecting solution each time.
  • Rub and rinse lenses if your solution instructions say to do so.
  • Replace lens cases often.
  • Never use saliva or homemade saline.

Water exposure is a known risk for contact lens related disease, including Acanthamoeba keratitis 4.

Common Questions About Acanthamoeba Keratitis

Yes. The risk is still low, but water exposure with contact lenses is a real risk factor 4.

Next Steps

  1. 1Remove contact lenses if the eye is red, painful, or light sensitive.
  2. 2Call an eye doctor today after contact lens water exposure with pain.
  3. 3Bring lenses, case, and solution to the appointment.
  4. 4Avoid tap water, showers, pools, lakes, and hot tubs while wearing lenses.
  5. 5Seek emergency care for chemical splash, injury, newborn red eye, or sudden vision loss.

Find specialists for Acanthamoeba Keratitis

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