Hygiene-related Diseases

Acanthamoeba keratitis (AK)

Acanthamoeba is a commonly occurring, free-living microscopic ameba that occurs naturally in the environment. It can live in treated and untreated water, soil, air (for example, cooling towers), sewage systems, and drinking water systems (for example, shower heads and taps). Although persons are regularly exposed to Acanthamoeba, contact with the ameba rarely results in illness. However, under some circumstances, Acanthamoeba is capable of causing infection.

Acanthamoeba keratitis (AK) is a rare infection of the eye that occurs when amebae invade the outer covering of the eye, called the cornea. AK can pose serious complications, such as severe pain, permanent visual impairment, and blindness. Although anyone can acquire AK, it is most commonly found in contact lens wearers. Early symptoms of AK infection may include eye pain, redness, blurred vision, light sensitivity, sensation that something is in the eye, or excessive tearing. Persons who suspect they may have AK should consult a physician.

AK may be prevented through appropriate contact lens hygiene. To help reduce the risk of eye infections, including Acanthamoeba keratitis, the following hygiene techniques should be followed by all contact lens wearers:

• Visit your eye care provider for regular eye examinations.
• Wear and replace contact lenses according to the schedule prescribed by your eye care provider.
• Remove contact lenses before any activity involving contact with water, including showering, using a hot tub, or swimming.
• Wash hands with soap and water and dry before handling contact lenses.
• Clean contact lenses according to the manufacturer's guidelines and instructions from your eye care provider.
  1. Use fresh cleaning or disinfecting solution each time lenses are cleaned and stored. Never reuse or top off old solution.
  2. Never use saline solution or rewetting drops to disinfect lenses. Neither solution is an effective or approved disinfectant.
• Store reusable lenses in the proper storage case.
  1. Storage cases should be rinsed with sterile contact lens solution (never use tap water) and left open to dry after each use.
  2. Replace storage cases at least once every three months.

Contact lens users with questions regarding which solutions are best for them should consult their eye care providers. They should also consult their eye care providers if they have any of the following symptoms: eye pain or redness, blurred vision, sensitivity to light, sensation of something in the eye, or excessive tearing.

For more information on Acanthamoeba keratitis, please visit CDC’s Acanthamoeba keratitis page.