Hard water probleem voor contactlens gebruikers.*
De meeste gebruikers van contact lenzen moeten contact van (hard) leidingwater met hun lenzen, bij opslag of zwemmen en douchen vermijden willen ze niet een drie keer zo’n hoge kans hebben geïnfecteerd te raken met acanthamoeba keratis, een infectie die zelfs gezichtsverlies kan veroorzaken.
Most contact lens wearers know that rinsing their contact lenses or storage containers in nonsterile water is a no-no. Now, a new study from the UK reports that people with "hard" tap water are three times more likely to become infected with acanthamoeba keratitis (AK), an infection that can cause vision loss. "This is the first study to suggest a significant increase in risk associated with supply of hard domestic water and a...variation in the distribution of a cases which appeared to be (at least partly) related to this," Dr. Cherry F. Radford, of Moorfields Eye Hospital in London, and colleagues write in the British Journal of Ophthalmology. In the study, Radford's team monitored AK infections in England and Wales over a 2-year period. The investigators also measured levels of calcium carbonate--a naturally occurring mineral--in the water supply. The presence of calcium carbonate relates to the "hardness" (high mineral content) or "softness" (low mineral content) of water. The team identified 106 cases of AK infections, the report indicates. During the study period, the average rate of infection among the general population in those areas monitored was roughly one case per one million people. Among contact lens wearers the rate of infection was about 19 cases per one million people, with those wearers in parts of England with a hard water supply most likely to be infected. "There appeared to be a significant trend towards an increased incidence of AK with increasing hardness of water supply, with hard water being...associated with a threefold increase in risk of AK when compared with soft water," Radford and colleagues write. "The fact that water quality can have such an effect on the risk suggests that many contact lens wearers must be letting nonsterile water come into contact with their lenses or storage cases," the authors add. Educating contact lens wearers about the risks associated with tap water and swimming or showering while wearing their contact lenses, the efficacy of various disinfection systems and the benefits of disposing of soft lenses after they expire can be expected to reduce the incidence of AK infection, the researchers conclude. SOURCE: British Journal of Ophthalmology 2002;86:536-542 (april 2002)
