The Centre for Health Protection reminds contact lens wearers to clean them properly following four cases of cornea inflammation in July and August.

Four public hospital patients suffered from microbial keratitis - a bacterial infection that can lead to blindness if not treated early. All four used various brands of soft disposable contact lens and disinfectants.

The patients, two men and two women aged 19 to 51, developed eye pain, redness and the sensation of some foreign body being stuck in their eye. Two required hospitalisation and all recovered after treatment.

Keratitis causes the eye's cornea to become inflamed. It is not uncommon among contact lens users. Patients with the illness sometimes become sensitive to light. Contact lens-related microbial keratitis is usually caused by bacteria and fungus.

Improper lens hygiene practice, such as wearing the lenses overnight, smoking and wearing the lenses continuously for a long time is associated with increased risk of contact lens-related microbial keratitis.