“Don’t swim in your contact lenses!”
Craig Dockter, O.D.
This advice should be given to all contact lens patients. On the surface it seems quite obvious why swimming with your contact lenses is not a great idea, since most contact lenses are generally lost from the open eye while submerged in water. But there is a more important reason for obeying this rule, one that is directly connected to the health of your cornea and that reason is Acanthamoeba keratitis (AK).
AK is a rare infection of the cornea caused by a microscopic, free-living ameba called Acanthamoeba. Acanthamoeba ameba are ubiquitous, found in bodies of water, soil, sewage systems, cooling towers and heating/ventilation/air conditioning (HVAC) systems. Infection primarily affects contact lens wearers, although 15% of infections occur in patients without a history of contact lens wear. Soft contact lens wearers are at greater risk than hard contact lens wearers, generally occurring in a ratio of about 9:1. There appears to be greater risk associated with the newer generation silicone hydrogel soft contact lenses than the conventional hydrogel soft contact lens. Contact lenses that have had a significant amount of wearing time, or age, appear to be at greater risk than a new set of contact lenses. The incidence of AK is difficult to measure, since practitioners are not required to report cases to the Centers for Disease Control and Prevention, but estimates range from 1 to 2 per million contact lens wearers to one per 30,000 contact lens wearers per year.
AK is difficult to treat due to lack of effective medications. The outcome is generally poor resulting in corneal scarring, which causes severe vision loss, or resulting in corneal transplant. Symptoms are variable between patients but include eye pain, eye redness, blurred vision, sensitivity to light, foreign body sensation, excessive tearing. The onset of symptoms may be slow to develop, and may last for weeks to months.
The Centers for Disease Control and Prevention (CDC) has compiled a list of practices that place contact lens wearers at risk:
- Storing and handling lenses improperly
- Disinfecting lenses improperly (such as using tap water or homemade solutions to clean lenses)
- Swimming, using a hot tub, or showering while wearing lenses (the risk is present in chlorinated water too)
- Coming into contact with contaminated water
- Having a history of trauma to the cornea
The CDC recommends the following guidelines to reduce your risk of AK:
- Visit your eye care provider for regular eye exams
- 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 lenses
- Clean contact lenses according to the manufacturer’s guidelines and instructions from your eye care provider.
- Use fresh cleaning or disinfecting solution each time lenses are cleaned and stored
- Never reuse or top off old solution
- 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
- Storage cases should be rinsed with sterile contact lens solution (never use tap water) and left open to dry after each use
- 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.