Communicable Diseases Series

Microbial Keratitis(for Contact Lens Wearers)

Microbial Keratitis(for Contact Lens Wearers)

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Keratitis is an inflammation of the cornea, which is the transparent front part of the eye. Microbial keratitis can be caused by bacteria, viruses, fungi and parasites, resulting in serious infection that potentially leads to permanent visual impairment or blindness. For example, Fusarium keratitis is a fungal infection of the cornea, while Acanthamoeba keratitis is caused by microscopic and free living amoeba.

Contact lens when worn is closely apposed to the cornea. Wearing contact lens is associated with increased risk of keratitis. The risk of microbial keratitis is increased by five to ten-fold among those who wear lens overnight and for prolonged period of time. Other important risk factors include poor compliance with lens care instructions and dirty storage cases. Smoking also increases the risk of microbial keratitis.

Clinical featuresMicrobial keratitis may present with eye pain, eye redness, blurred vision, sensitivity to light, foreign body sensation in the eye, excessive tearing or other eye symptoms. Untreated infection can affect visual acuity or even cause loss of vision, which requires corneal transplantation to recover the vision.

ManagementEarly diagnosis is essential for effective treatment of contact lens related microbial keratitis. If you have symptoms of keratitis, seek medical advice immediately.

PreventionTo prevent contact lens related microbial keratitis, contact lens wearers are advised to:

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Before handling contact lens, contact lens solutions or related accessories, wash hands with liquid soap and water, and rub for at least 20 seconds. Then rinse with water and dry thoroughly with a disposable paper towel or hand dryer.

Clean and disinfect your contact lens properly.

Have regular check-ups by your optometrist or ophthalmologist and follow their professional advice.

Remove contact lens before any activity involving contact with water, including showering, using a hot tub or swimming.

Remove contact lens whenever you feel discomfort or develop redness and seek advice from your optometrist or ophthalmologist.

Seek medical advice promptly if symptoms persistdespite removal of contact lens.

NEVER wet your lens with saliva, bottled water or tap water.

NEVER wear your lens while sleeping, swimming or taking shower or beyond the recommended period.

Remember the followingimportant points on:CLEAN & DISINFECTIONClean and disinfect contact lens according to instructions from your eye care provider and the manufacturer's guidelines

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Be sure to clean, rub, and rinse your lens each time you remove your lens BEFORE soaking for disinfection. Rubbing and rinsing your contact lens will aid in removing harmful microbes and residues.

The multi-purpose solution in the lens storage case must be changed every day even if the lenses are not used daily; never reuse or top up solution. Use fresh cleaning or disinfecting solution each time lenses are cleaned and stored.

Never use tap water, bottled water, saline solution or rewetting drops to disinfect or store contact lens. Neither solution is an effective or approved disinfectant.

Close all bottles of contact lens solution properly after use.

Discard contact lens solutions 1 month after opening.

CARE OF LENS CASEStorage case should be cleansed, rinsed with sterile contact lens solution (never use tap water or bottled water) and then left open to dry after every use.Store your contact lens, solutions and accessories in a cool dry place.

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Replace storgae case every 3 months.

CARE OF LENSDisposable contact lens must not be used beyond their recommended disposal period.

Store reusable lens in the proper storage case.

Follow your optometrist’s or ophthalmologist’s advice to replace the lens at the intervals specified.

Centre for Health Protection Website www.chp.gov.hk

Health Education Infoline of the Department of Health 2833 0111

Revised in December 2019