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You Won’t Believe What’s Living In Your Contact Lens Case

Posted by techmatters 10/07/2014 0 Comment(s)

Do you remember the last time you replaced your contact lens case? If you can’t remember then you need to throw out that case immediately and by immediately, I mean today.

Studies conducted on contact lens cases that had been in use from under a month to two years showed that around 60 percent of contact lens cases had microbial contamination with up to 105 organisms per case well.[1] The most common micro-organisms found in these cases was coagulase negative staphylococci, Bacillius spp. and fungi. Contact lens cases are a recognised potential source of pathogens associated with corneal ulcers, a serious complication of wearing contact lenses that can lead to blindness.

Have you thrown that case away yet?

Eye infections from contaminated lens cases can be bacterial or fungal. Signs that you may have an infection include discomfort, excess tearing or other discharge, unusual sensitivity to light, itching, burning, gritty feelings, unusual redness of the eyes, blurred vision, swelling and pain. Sometimes these symptoms may be a result of allergies.  The main way to tell if you have an allergy or an infection is that an allergy is accompanied by itching and watery discharge and both eyes are affected in the same way. If you have any of these symptoms and suspect an infection, see your optometrist as soon as possible for diagnosis and treatment.

So why is contamination in contact lenses so high?

The two biggest reasons are poor hygiene and biofilm formation.

Poor hygiene. Whilst you might think that you’re caring for your case properly, chances are you’re not. Most people are diligent about cleaning their contact lenses but the actual contact lens case is often ignored. We’ll talk about the best way to care for your contact lens case in a moment.

Biofilm formation[2]. Yes, it’s as bad as it sounds and it’s happening in your contact lens case. A biofilm is any group of organisms in which cells stick to each other on a surface resulting in inherent microbial resistance.[3]  Biofilm helps bacteria to ‘hide’ from the disinfecting solution and is invisible to the naked eye. That translates to germs living in your contact lens case even after they have been exposed to contact lens cleaning solution.

So how do we get rid of these nasty germs?

Replace your contact lens case frequently.  We recommend that you replace your case on a monthly basis or at the very least when you open up a new bottle of contact lens solution. A new contact lens case is usually included when you purchase contact lens solution so there’s no excuse!

Clean your contact lens case. Once you have put your contact lenses on, empty out any remaining solution, give each case well a good rub with clean fingers and rinse again with solution. Wipe dry with a clean tissue or cloth. Avoid washing with tap water as this has been linked to an increased risk of developing Acanthamoeba keratitis, a severe cornel infection, resistant to treatment and cure, which can lead to permanent vision loss.[4]

Air-dry your contact lens case. Don’t recap the lid on your case once you’ve put your contact lenses on. Air-dry your case instead, face down on a clean piece of tissue paper. Doing this will minimise air borne contamination.[5]

Clean your contact lenses properly. See our article on Inserting, Removing and Caring for your Contact Lenses for tips on the best way to clean your contact lenses.

So, have you thrown that case away yet?


Article written by Jen-Ni Quante - General Manager, eContactLenses
[1] Wu Y, Zhu H, Harmis N, Iskandar S, Willcox M, Stapleton F. Profile and frequency of microbial contamination of contact lens cases. Optom Vis Sci 2010; in press.
[2] Dart J. The inside story: why contact lens cases become contaminated. Cont Lens Anterior Eye 1997; 20: 113-118
[3] Lakkis C, Fleiszig SMJ. Resistance of Pseudomonas aeruginosa Isolates to Hydrogel Contact Lens Disinfection Correlates with Cytotoxic Activity. J Clin Microbiol 2001; 39: 1477-1486.
[4] Mutoh T, Ishikawa I, Matsumoto Y, Chikuda M. A retrospective study of nine cases of Acanthamoeba keratitis. Clin. Ophthalmol. 2010;21(4):11890-92.
[5] Wu Y, Zhu H, Willcox MD, F S. Effects of lens case drying position and location on contamination levels. Optom Vis Sci 2010; 87: in press.