contact lens Q&A

What Your Patients Need to Know About Tap Water

BY DAVID I. GEFFEN , OD
JULY 1998

We have received many questions regarding the use of tap water by contact lens patients. The principal concern in using tap water to clean contact lenses is infection, and acanthamoeba is the

is the most feared culprit. Elimination of homemade salines by removing salt tablets from the marketplace has greatly reduced the reported incidence of acanthamoeba keratitis. However, the condition is still a concern with the use of standing water and tap water in the eye. Bacterial infections are also of concern with the use of tap water, as well as lens contamination from impurities and chemicals found in tap water.

What's the concern about using tap water with soft lenses?

ANSWER: With soft lenses, I feel safe saying that no practitioner would recommend using tap water directly. Although salt tablets have been removed from the market, we still need to instruct our patients to use only approved rinsing and disinfecting solutions with their lenses.

I recommend that patients wash their lens cases with warm water, followed by a rinse with their approved disinfectant. I make sure that soft lens patients are aware of the potential dangers of allowing their lenses to come into contact with water. I also make sure to address the risks for water-induced contaminants and infections associated with the lens material that the patient is wearing, since high water content lenses are more susceptible to contamination than low water content lenses. Obviously, the consequences of using tap water with soft lenses are much more serious than with rigid lenses.

Is it safe to use tap water with rigid gas permeable lenses?

ANSWER: Most patients use tap water to rinse the cleaner off of their rigid gas permeable contact lenses. Patients generally try to economize the use of their solutions and therefore do not see the benefit in rinsing the cleaner off of the lenses with the conditioning solution. As most practitioners are aware, it takes a great deal of conditioning solution to thoroughly rinse the lens.

In our office, we handle this problem by instructing patients to clean their lenses with their approved gas permeable cleaner and rinse the cleaner off of the lenses with tap water. Then we tell them to do a final rinse with a small amount of conditioning solution before storing the lenses overnight in fresh conditioning solution. In the morning, patients should take their lenses from the case and rinse them briefly with a small amount of fresh conditioning solution before placing them on their eyes. Warn patients to never place their lenses in their eyes after rinsing with tap water. While a soft lens that has been exposed to tap water must be cleaned and disinfected with recommended solution, RGPs just need to be rinsed off with solution. Also, warn patients to never put their lenses in their mouth and then on their eyes.

It would be nice if we could prevent our patients from using tap water altogether, but realistically, we must assume that our patients will ultimately use tap water to rinse lenses. We must therefore be diligent in our effort to protect our patients from possible infection and contamination. Stressing the importance of not allowing tap water directly into the eye is imperative.

Dr. Geffen is in a joint refractive surgery practice in San Diego. He is also a consultant for Infinity Optical.