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28 Jun 2017

Microbial Infections of the Cornea AKA Acanthamoeba Keratitis

Acanthamoeba eye infections in contact lens wearers are rare but serious, and they often start because of improper lens handling and poor hygiene.

What Are Acanthamoeba?

Acanthamoeba are naturally occurring protozoa (tiny, one-celled animals) commonly found in water sources, such as tap water, well water, hot tubs, and soil and sewage systems.

If these tiny parasites infect the eye, Acanthamoeba keratitis (AK) results. 

Whilst our immune systems are able to deal with Acanthamoeba under normal circumstances contact lens wearers are potentially more vulnerable to this sight threatening disease. If tap water comes into contact with your contact lenses or contact lens case the protozoa will be introduced into the eye with the contact lens waiting to exploit any compromise in the corneal integrity caused by something as simple as rubbing your eye.

One of the issues with Acanthamoeba is that it is very difficult to kill. It has two forms; in its trophosite form it is at its most virulent and its most vulnerable, however when it is attacked (by a disinfectant agent for example) it changes in to it’s cystic form and whilst dormant in this form becomes almost invulnerable. Once the threat is passed it returns to its “predatory” form.

It is rare (about 3 in 10,000) but it does seem to be on the increase. The good news is that you can protect yourself by ensuring that you don’t let water near your eyes when wearing lenses or your contact lenses and case. Fully comply with the hygiene regime given to you by your optician and don’t take shortcuts and you can safe guard your eyes.

How would I know if I have AK.

AK manifests itself by extreme photophobia (Light sensitivity to the stage of being unable to open your eyes), extreme pain, intense watering of the eye and attendant loss of vision.

If you ever suffer from these symptoms ring us immediately but also go straight to your local hospital eye department taking both your contact lenses and contact lens case so the medics can culture them to get an accurate diagnosis. Remember time is of the essence so don’t delay.

The absolute best plan is avoidance and you can do this by following this advice;

  1. Do not wear contact lenses over night or an extended basis.
  2. Do not allow tap water to come near your contact lenses or contact lens case.
  3. Replace your contact lens case monthly.
  4. Do not shower or bath wearing your contact lenses.
  5. Following a hand wash ensure you dry your hands throughly before handling your contact lenses.
  6. Do not swim in your contact lenses.
  7. Do not use any liquids or solutions with your contact lenses other than those prescribed by your contact lens optician.
  8. Follow your cleaning regime to the letter.

If you want to know more please contact your contact lens optician or optometrist who will be pleased to answer your questions.

And remember;

Your Vision is Precious - Don’t take chances with it.


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