All Posts Tagged Tag: ‘Acanthamoeba’

Acanthamoeba Keratitis.


I had a young man in earlier who was wearing a pair or Air Optix monthly replacement contact lenses, bought from an optician’s in Navan, from our prescription though.

He ran out of lenses about 1 month ago, so has been wearing this pair for two months now. To be fair the lenses looked in not too bad condition, but we cannot advise or condone wearing a medical device (which a contact lens is), for longer than it is designed, or licenced to be worn.

BUT…. he ran out of contact lens solutions also approximately 1 month ago, so he has been using — TAP WATER.

Tap water can commonly contain Acanthamoeba, which can cause devastating corneal infections – potentially sight threatening infection. Tap water does not kill bacteria, which will naturally be on the surface of the contact lenses – you need to clean the contact lenses and store them in an approved solution to kill off the the bugs which were not rubbed off. Acanthamoeba eat the “Biofilm” on the contact lens (the bacteria, mould spores, mucus and other contaminants which coat the lens during wear) so if there is no contamination on the lens there is less for an amoeba to eat. But if they get into your cornea, they will start eating the nerves in your cornea, which as you can imagine may “smart” a little. Often a “red flag” for an acanthamoeba infection is a very incredibly painful eye, with little sign that it should be so sore – it can take a while for the problems to begin to show up on examination.

Acanthamoeba Keratitis.Never ever ever store your contact lenses in tap water. You should not even ever allow water to get onto your contact lenses, which means thorough hand drying before handling the lenses (you did just wash your hands, didn’t you??) I gave him a new pair and told him to throw the old ones away. I also gave him some solutions to tide him over until his valuepack arrives.

This lad seems to have gotten away with it, hopefully, but I advised him (again) never to mix tap water with contact lenses. But I did advise him never to mix tap water with contact lenses when I originally fitted him, and taught him how to apply and remove them…. OK, that was a good few years ago, but just one more time…. DO NOT MIX TAP WATER AND CONTACT LENSES, AT ALL EVER!

We have a contact lens dos and don’ts on the website – it might not be a bad idea to have a quick refresher if you wear contact lenses.


Acanthamoeba Keratitis.

Acanthamoeba Keratitis

Acanthamoeba Keratitis is a serious corneal infection caused by a free living parasitic protozoan (amoeba), which is commonly found in water and soil. The Center for Disease Control in the USA recently had a look at the risk factors for this serious corneal infection. Unsurprisingly contact lens wear is a significant (the biggest) risk factor, but still contact lenses ARE SAFE, as long as you follow all the guidelines.

Contact Lens hygiene is the most significant way to reduce the risk of infection, and although mostly we are concerned about bacterial corneal infections, improper lens care also increases the risk of Acanthamoeba Keratitis (AK).

Minimise your risk by following the lens care instructions properly. Even if your care solutions claim to be “No Rub”, we would always suggest a 10 second rub and rinse of the lenses- on removal a lens is covered in a biofilm- mucus, protein, bacteria, molds, cosmetics, and anything else which may have drifted into your eye during lens wear. This biofilm is a food source to acanthamoeba, so clean contact lenses mean less risk. Also, because the solutions can get straight to the lens surface, they can begin disinfection immediately, and a simple rub and rinse will reduce the bacterial contamination on the lens 100000 fold, which means there are less for the solution to deal with.

Never EVER reuse contact lens solutions- people who admitted that they “topped off” their solutions are hugely greater risk (4x) -they were just adding to the solution left over in their case from the previous days (or weeks)- there is no way to guarantee the efficacy of used solutions! Every day the solution should be discarded and the storage case left to air dry.

Other stated risk factors are people who wear lenses less than 12 hours per day, the under 26s and over 55s, and wearers who have worn lenses for less than 5 years. The CDC attempted no explanations of the findings at this time, only the statistics. This author cannot see any reason why longer contact lens wear, longer than 12 hours would reduce the risk.

Acanthamoeba is particularly a problem where water is stored in tanks before use- in some countries, modern houses have mains water to every tap, but in Ireland this would be very rare. All contact lens wearers should attempt to minimise their exposure to water when wearing lenses- shower before putting them in, don’t swim in them (or if you must, discard them afterwards and put a new pair in). Hot tubs are a particular worry, as they are at a perfect temperature to breed all kinds of bacteria which can cause eye infection and again act as a food source. Tap water may be safe to drink and wash hands, but it should not be used on lenses or their case- the case should be regularly cleaned and rinsed with the care solution paying attention especially to the threads. The CDC recommended at least 3 monthly case replacement to prevent a risk increase.

We would expect that all of the above is not news to our own contact lens patients- we believe that the risks and “do’s and dont’s” should be clearly explained to all our patients when they are fitted with lenses and taught application and removal.

If you are taking chances- if any of the risk factors above apply to you, it would be best to change your ways before problems occur!

Contact Lenses are safe if used correctly.

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