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Acanthamoeba Keratitis: The Sight Thief Of Contact Lens Wearers

Acanthamoeba keratitis is an infection of the cornea (the transparent structure which covers the iris and the pupil) caused by a parasite called acanthamoeba. 

It is a parasitic keratitis most commonly seen in contact lens wearers particularly with improper handling of contact lens and using low quality contact lens solution. 

The recent infamous case regarding parasitic keratitis caused by acanthamoeba was the recall of Complete MoisturePlus Multi Purpose Solution in May 2007.

This contact lens solution which is manufactured by Abbott Medical Optics (AMO) — formerly Advanced Medical Optics, was associated with an outbreak of Acanthamoeba keratitis that affected 138 people.

What Are Acanthamoeba?

The deadly creature - Acanthamoeba

Acanthamoeba are microscopic naturally occurring amoeba (single cell organism) that can be commonly found in soil, air and water sources such as river, sea, tap water, swimming pool and well water.

When Acanthamoeba gets onto your eye, it adheres to the cornea and secrete a certain type of protein that dissolves the surface of the cornea.

The amoeba then feeds its way into the cornea and causes ulceration

The process is extremely painful and can cause blurred vision. If left untreated, the disease can cause permanent corneal scarring and eventually blindness.

Symptoms And Signs

The symptoms of acanthamoeba keratitis can be very similar with other eye infections particularly conjunctivitis (pink eye).

Therefore, you should not take it light if you have the symptoms stated below. 

  • Blurred vision
  • Eye pain
  • Excessive tearing
  • Eye redness or appear bloodshot
  • Sensitivity to light
  • Foreign body sensation in the eye
  • In severe cases, the normally clear cornea looks gray or whitish

Please see your doctor immediately to avoid permanent blindness.

What Causes Acanthamoeba To Get Onto Your Eye?

Even though it is possible for anyone to get it, Acanthamoeba keratitis is most commonly seen in contact lens wearers.

Factors that increase the risk of getting Acanthamoeba on your eye include:

  • Improper handling and storing of contact lenses.
  • Coming in contact with contaminated water.
  • Using of ‘no-rub’ contact lens solution.
  • Wearing contacts into bodies of water such as swimming, showering and using of hot tub.
  • Disinfecting lenses improperly (such as using tap water or homemade solutions to clean the lenses).
  • Having a history of trauma to the cornea.

Treatment For Acanthamoeba Keratitis

Detecting and treating the condition early offers the best result for treatment. 

To determine the best course of treatment, your doctor will scrape off a piece of the acanthamoeba for examination or use a process known as confocal microscopy to check on the growth of the acanthamoeba.

Eye infection from acanthamoeba is difficult to treat. It often requires a mixture of multiple topical antibiotics to kill the infection. 

If the condition does not respond to treatment and permanent scarring occurred, corneal transplant may be required if it affects normal vision.


Proper hygiene and disinfection

The best treatment for acanthamoeba keratitis is prevention.

It is difficult to get it treated once you are infected with acanthamoeba. 

The best prevention for contact lens wearers, who are most at risk for contracting this disease, is to stop wearing it.

Wearing contact lens is associated with too many risks other than acanthamoeba infection.

If you have to wear contact lenses no matter what, good hygiene and proper handling of contact lens can reduce the risks parasitic keratitis.

They include: 

  • Having regular eye examinations.
  • Always wash your hands with soap and water before handling lenses.
  • Never use tap water, saliva or even saline lotion to clean or lubricate the lens. Use proper lens solution.
  • Never reuse an old contact lens solution and don’t buy any lens solution just because they are on discount. It may not be appropriate for your lenses.
  • Follow the your eye doctor and the manufacturers' guidelines in caring for your lenses.
  • Using fresh disinfecting solution each time lenses are cleaned and stored; never reuse or topping off with old solution. 
  • Soak your contact lens in new disinfecting solution every night.
  • Wash your storage cases with sterile solution (not tap water) and leaving them open to air dry. 
  • Replacing storage cases once every three months

Contact lenses should also be removed before you start any activity involving water, including showering, soaking in hot tub or swimming.

If you desperately needed them for swimming, wear a swimming goggles over it and dispose the lens immediately after finishing the activity.

Learn more about how to handle contact lens properly in Fatal Mistakes Of Contact Lens Wearers.

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