LONDON -- Contact lens users should choose their cleansing solutions carefully and may need to take extra measures to kill organisms that can cause a rare eye illness, Reuters quoted Austrian scientists as saying on Tuesday.

Professor Horst Aspock of the Clinical Institute of Hygiene in Vienna, found that not all disinfectant cleaners can destroy the harmful bug Acanthamoeba, an important cause of eye infection in contact lens users that could lead to keratitis which can cause blindness.

People wearing soft contact lenses have the highest risk of the disease, according to Aspock.

He advised contact lens wearers to use a two-step hydrogen peroxide system because it can kill both life stages of the organism. Boiling and microwaving can also destroy the eye bug.

"The main message is to use a two-step system and to replace (contact lens) storage cases as frequently as possible," he said.

Acanthamoeba are found most commonly in soil and dust and in brackish water. It can enter the skin through a cut or wound or the eye via a contact lens. Storage cases can be a breeding ground for the organisms.

In a study reported in the British **** Journal of Ophthalmology ****, Aspock and his colleagues tested three types of disinfecting solutions -- a multipurpose and a one-step and two-step hydrogen peroxide system.

After eight hours all the solutions had killed one life stage of acanthmoeba but the two-step solution was most effective in killing both.