cleaning lens case with tap water?

Discussion in 'Optometry Archives' started by Ian Upright, Aug 7, 2003.

  1. Ian Upright

    Ian Upright Guest

    Someone told me that it is dangerous to clean your contact lens case with
    tap water.. (assuming afterwards, you let it stand to dry for many hours).
    I figured the organizims would be dead and dried up if you let it dry
    completely anyways. Also, what miniscule amounts of organisims are left,
    wouldn't they be killed off by the solution?

    I've also heard that you must boil your lens case every week to keep it
    clean, but wouldn't the solution act as a sterilizer anyways and kill off
    whatever is in there?

    Thanks, Ian
    Ian Upright, Aug 7, 2003
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  2. I had that very thought in mind, Ian, when I posted my original
    question here this morning about what's the best way to clean lens
    cases--that if you leave a case wet with water, bacteria could end up
    growing in the moisture. When I rinse my case and leave it
    upside-down on a paper towel to dry, I notice that the inside bowls of
    the case are almost instantly dry (they are so smooth that water
    apparently won't stick to them), but moisture occasionally remains on
    the inside of the caps (around the crease of the rim) even 24 hours
    Many pathogens can survive for a time on dry surfaces (I assume
    because their cell walls or protein coats seal in their own water). I
    don't know if any of the ones that cause eye infections do.
    I've been thinking that exact same thing too. If there are any
    leftover bacteria, I would think that the solution would kill them
    off. If, however, as Mike pointed out, a fungal film begins to form
    on surfaces that the solution doesn't normally soak, I could see how
    bacteria could survive protected on or inside the film, and perhaps
    get transferred to the lenses or your fingers when they are removed
    from the case.

    If any doctors reading this know of a published study that discusses
    the mechanism through which old lens cases cause infection, I would be
    very interested to read a summary. I wonder if it is only people who
    are not careful about rinsing their cases who experience such
    problems, or if it is inevitable that any case will eventually become
    unsafe to use.

    Lothar of the Hill People, Aug 8, 2003
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  3. Ian Upright

    The Real Bev Guest

    I am a slob. When they came out with that study showing that children
    raised in, um, untidy homes got fewer colds and other infections than
    those raised by the neat-freaks I told everybody I knew "SEE?"

    That being said, I rinse my case in cold water (it takes forever for the
    hot water to get to the tap), let it dry upside down loosely wrapped in a
    paper towel, and use the same case for months. If I were worried about it
    I'd soak the case in a mild bleach solution every once in a while and
    rinse well. I do, however, always wash my hands with disinfectant soap
    before inserting or removing my lenses. I'm lazy, not stupid!

    "Even Islamic terrorists don't hate America like liberals do.
    They don't have the energy. If they had that much energy,
    they'd have indoor plumbing by now." -- Ann Coulter
    The Real Bev, Aug 8, 2003
  4. The problem is that the organism Acanthamoeba is present in tap water and
    this can
    lead to a rather nasty keratitis, which if not treated promptly can be sight

    If acanthamoeba is present in the case, if you leave it to dry out then the
    organism goes into
    a cystic state which preserves against any further dessication and survives
    until it is
    rehydrated. The problem is that in its cyst form it is resistant to nearly
    all MPS solutions,
    except in very high concentrations. The only methods of disinfection that
    are really effective
    are heat or hydrogen peroxide.


    Ian Hodgson - Isle of Man
    Ian Hodgson Opticians Ltd, Aug 8, 2003
  5. Thanks, Ian, that's exactly the kind of info I was looking for! That
    reinforces my idea to rinse my case with hydrogen peroxide or alcohol.
    I suspect that alcohol is none too good for the eyes if a drop makes
    contact accidentally, but can anybody tell me what hydrogen peroxide
    would do? I expect that neither one would leave any sort of residue
    in an air-dried case anyway, so this shouldn't even be a concern.

    Lothar of the Hill People, Aug 8, 2003
  6. Okay, thanks Mike. So it sounds like peroxide should be perfectly
    fine to use as a lens case rinse. I wonder if 70% isopropyl alcohol
    would be just as appropriate for sanitizing. It would certainly
    evaporate faster.

    Lothar of the Hill People, Aug 8, 2003
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