contact lens care

Protecting Your Patients from Acanthamoeba Infection

BY SUSAN J. GROMACKI, OD, MS, FAAO

Although rare, the incidence of Acanthamoeba keratitis is on the rise. The majority of affected patients (90 percent) are contact lens wearers. In the recent outbreak documented by the United States Centers for Disease Control and Prevention (CDC) in May 2007, 58 percent of culture-confirmed soft contact lens-wearing patients had been using Complete MoisturePlus Multipurpose Solution (Advanced Medical Optics), which was disproportionate to its approximate 9 percent market share. As a result, AMO voluntarily recalled the product.

Research had previously demonstrated Complete Moisture Plus' diminished efficacy against Acanthamoeba, but the United States Food and Drug Administration does not require contact lens solutions to kill amoebae. What, then, can we practitioners do to prevent our patients from contracting this often debilitating corneal condition?

Reinforcing the Rules

First, we have to know that amoeba love water — all kinds of water: lakes, streams, swimming pools, hot tubs, well water and tap water. Secondly, amoeba feed on bacteria. So, we need to eliminate any contact between water and a patient's contact lenses and lens case as well as eradicate the bacteria.

Here are some recommendations from The American Optometric Association for specifically preventing Acanthamoeba infection. It would be wise to adopt them for all of your contact lens-wearing patients.

Figure 1. Acanthamoeba keratitis.

• Always wash hands before handling contact lenses.
• Rub and rinse the surface of the contact lens before storing.
• Avoid using tap water to wash or store contact lenses.
• Discard contact lens solution upon opening the case; use 100 percent new solution each time the lens is placed in the case.
• Replace lenses according to your practitioner's schedule.
• Do not sleep in contact lenses unless prescribed by your practitioner.
• Never swap lenses with someone else.
• Never put contact lenses in your mouth.
• Every day, mechanically scrub (using a clean washcloth or new toothbrush) the inside and outside of the contact lens case with sterile contact lens disinfecting solution.
• Avoid using tap water to wash or store lens cases.
• Air dry your contact lens case when not in use. Cover case with a clean towel. (Exception: the ProGuard case, used with Aquify Multi-Purpose Solution [CIBA Vision], should be closed to maintain its antimicrobial properties.)
• Replace the lens case every one to three months.
• Do not swim, shower or use a hot tub while wearing contact lenses.

The AOA has provided this comprehensive checklist. Whether presented by you or your technician, verbally or in writing (preferably both), it is our ethical responsibility to give patients the information they need to prevent eye infections. CLS

For references, please visit www.clspectrum.com/references.asp and click on document #147.

Dr. Gromacki is a Diplomate in Cornea and Contact Lenses in the American Academy of Optometry. She has a specialty contact lens and post-surgical co-management practice as part of a multi-subspecialty ophthalmology group in Ann Arbor, MI.