Acanthamoeba Keratitis

Back in August I put up a blog called “Is Your Contact Lens Case a Danger?”  and last Monday I shared an article by Invision about how this infection is on the rise. Today I am posting some information about this infection, Acanthamoeba Keratitis.

Acanthamoeba keratitis is a rare but serious infection of the eye in which amoebae invade the cornea of the eye, which can result in permanent visual impairment or blindness. This infection is caused by a microscopic, free-living ameba (single-celled living organism) called Acanthamoeba. Acanthamoeba causes Acanthamoeba keratitis when it infects the transparent outer covering of the eye called the cornea. Acanthamoeba amoebas are very common in nature and can be found in bodies of water, sources such as tap water, well water, lakes and ocean also swimming pools, hot tubs, and soil, air and sewage systems.

The ameba can be spread to the eyes through contact lens use, cuts, or skin wounds or by being inhaled into the lungs. Most people will be exposed to Acanthamoeba during their lifetime, but very few will become sick from this exposure.

Recently, there have been increasing reports of Acanthamoeba keratitis, which is a co-infection of Acanthamoeba with a bacterial keratitis. This infection commonly occurs in the contact lens case and on the cornea, complicating prevention, diagnosis and treatment.

How You Can Reduce the Risk of Getting Acanthamoeba Keratitis?

There are several easy ways to greatly reduce the chance of getting this sight-threatening condition — and, in fact, any type of contact lens-related eye infection:

  1. Follow your eye doctor’s recommendations regarding care of your contact lenses. Use only products that he or she recommends.
  2. Never use tap water with your contact lenses. The FDA has recommended that contact lenses should not be exposed to water of any kind.
  3. Do not swim, shower or use a hot tub while wearing contacts. If you do decide to wear your lenses while swimming, wear airtight swim goggles over them.
  4. Soak your lenses in fresh disinfecting solution every night. Don’t use a wetting solution or saline solution that isn’t intended for disinfection. Over the past few years some contact solutions have been pulled off from the shelves due to the ineffectiveness to control evolving bacteria.
  5. Always wash your hands with soap and warm water, before handling your lenses.
  6. Always clean your contacts immediately upon removal (unless you are wearing disposable contact lenses that are replaced daily). To clean your lenses, rub the lenses under a stream of multipurpose solution — even if using a “no-rub” solution — and store them in a clean case filled with fresh (not “topped off”) multipurpose or disinfecting solution. Also, avoid letting the tip of the solution bottle touch the case, as it can carry bacteria and contaminants.
  7. The American Optometric Association recommends you replace your contact lens storage case at least every three months.

Image: Acanthamoeba is a single-cell organism that exists in nature in two forms: an active, growing form (left) and a dormant, stress resistant cyst (right). (Images: Jacob Lorenzo-Morales, Naveed A. Khan and Julia Walochnik [CC BY 2.0], via Wikimedia Commons)



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