Expatriate medical insurance policyholders who use contact lenses ought to treat these items with care, a healthcare worker has said.
Visual Edge Optometrist member Nick Dash said these are "technically classified as medical devices".
This is because they are positioned in such a way as to be in close contact with a sensitive body part, he pointed out.
Therefore, it is essential that these are maintained and cleaned properly, as serious problems relating to vision can occur if due care and attention is not taken, the expert claimed.
However, 20 per cent of people have tried alternative products instead of contact lens solution to wash these devices, a recent study undertaken on behalf of Biotrue multi-purpose contact lens solution indicated.
Butter, fruit juice, baby out, coke, beer, lemonade and petroleum jelly are some of the alternatives that were used instead of the correct product.
Saliva or spit was a common alternative, but the study argued the average adult's mouth hosts between 500 and 1,000 different kinds of bacteria so this is dangerous and inappropriate.
Furthermore, although 16 per cent of contact lens wearers admitted using water to clean them, the investigators noted distilled or tap water is associated with microbes that can damage vision, including Acanthamoeba keratitis, which is resistant to treatment and infects the cornea.
Proteins are not successfully removed and the lenses are not disinfected when water is utilised, so discomfort is also a risk due to a material build-up on the devices, the researchers pointed out.
Mr Dash said using liquids and other substances to clean contacts is not a matter to be "taken lightly", as it can cause serious, lasting harm.
"Only the correct solutions" should be used, he continued.
The expert recommended conditioning and cleaning lenses properly in order to keep eyes safe and reduce the likelihood of future problems occurring.