Study shows Acanthamoeba risk

A high percentage of contact lens cases in Tenerife are contaminated with Acanthamoeba that cannot be killed by normal CL solution, according to November's Journal of Medical Microbiology.

Scientists at the University of La Laguna looked at 153 CL cases, 90 containing lenses, from people with no sign of the infection. Some 66 per cent of the cases and lenses were contaminated with pathogenic Acanthamoeba and 30 per cent of the amoebae were highly pathogenic. No pathogenic strains were found in daily CLs, but several were isolated from monthly and bi-monthly lenses.

Dr Basilio Valladares said cases were contaminated when rinsed in tap water. Antibiotic ciprofloxacin and the antiseptic chlorhexidine were found to kill Acanthamoeba, but the concentrations of chlorhexidine in CL solutions were not high enough to kill pathogenic strains and protect against amoebic keratitis, he added.