Safe use of cheap distilled water to clean contact lens

Discussion in 'Contact Lenses' started by George Bray, Aug 4, 2004.

  1. George Bray

    George Bray Guest

    I am thinking of using the de-ionised water sold for topping up car

    Now I know the battery water may be crawling with bugs, so I intend
    taking some precautions. Will my precautions be sufficient, or am I
    still running a big risk?

    1: Boil the battery water for ten minutes in a covered saucepan on the
    stove. This should kill most bugs.

    2: Add a pinch of (non-sterile) table salt, for what it's worth, to
    resemble saline solution. Also add a couple of drops of hydrogen
    peroxide solution, since I noticed there's a bit of that in commercial
    saline solution. It might help keep the bugs at bay.

    3: Dissolve a protein tablet in my DIY saline solution and leave the
    lens soaking overnight.

    4: Rinse lens with more DIY saline solution.

    5. Place in hyrdogen peroxide (stage 1) cleaner and leave for at least
    an hour.

    6. Neutralise (stage 2) and wear.

    Logic: the boiling and hydrogen peroxide process will kill all bugs.
    DIY saline is cheaper than using commercial solutions, other than for
    final disinfection by hyrogen peroxide or heat treatment.

    I read that pure distilled water can expand the thickness of soft
    contact lenses, and damage them, but I simply cannot believe it. How
    can distilled water with a pinch of salt be significantly different to
    commercial, sterile saline solition?

    George Bray, Aug 4, 2004
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  2. Yes, but only when boiled. The bugs will grow in whatever
    bottle you put your "saline". Acanthamoeba spores are
    very resistant.
    Somewhat. The problem is keeping it sterile.
    Believe! Or read up on the chemistry of polymer hydrogels.
    Osmotic pressure if you con't match concentrations. Put an
    old lens in very salty water and watch it shrivel.

    -- Robert
    Robert Redelmeier, Aug 4, 2004
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  3. George Bray

    The Real Bev Guest

    Commercial saline is dirt cheap. While I'm as eager as the next person
    to save a buck, in this case it seems like more trouble than it's

    "America is at an awkward stage: it is too late to work within the
    system, but it is too early to shoot the bastards." -Claire Wolfe
    The Real Bev, Aug 6, 2004
  4. George Bray

    Dr. Leukoma Guest

    (George Bray) wrote in
    Acanthamoeba is a ubiquitous (i.e. found in many places) unicellular
    organism. It exists in trophic and cystic forms. The cysts are difficult
    to kill and can remain dormant for a long, long time. It takes about 6
    hours of exposure to 3% hydrogen peroxide to kill them. Acanthamoeba has
    been isolated from bottled distilled water commonly found in the grocery
    store. It is also found in swimming pools and hot tubs.

    Acanthamoeba infection of the cornea is virtually unknown in anybody except
    contact lens wearers, whose lenses have become contaminated with water from
    the tap, hot tubs, swimming pools, lakes, etc. Acanthamoeba infections are
    historically difficult to treat, and a fair number have required corneal
    transplants, only to have the graft become re-infected by the organism. I
    have seen two cases within the past couple of months. One case had
    suffered a self-inflicted eye injury while wearing her contact lens, and
    had put ice on her eye following the injury. The source of infection was
    presumably the ice made from tap water. The second case reported having
    been swimming in a backyard pool while wearing contacts within days of the
    infection. Both cases were caught very early, and all the organisms were
    eradicated - hopefully.

    Do you still want to take the risk?

    Dr. Leukoma, Aug 6, 2004
  5. George Bray

    George Bray Guest

    Thank you Dr G and others who have contributed, for your warnings,
    which I take seriously.

    Commercial saline isn't exactly dirt cheap from UK shops, being about
    £3 for 500ml.

    My final stage would always be a long soak in 3% hydrogen peroxide
    (stage 1) solution. After your warning, I will make sure I leave them
    for at least 6 hours. I normally leave the lens in hydrogen peroxide
    for 8 or 9 hours. Is that enough to eliminate almost all the risk from
    using de-ionised car battery water in the first place?

    The other risk appears to be damage to the lens plastic if I use the
    wrong concentration of salt. So I will endeavor to find out the
    concentration used in the medical saline solutions and/or the
    concentration of salt in human tears, which I guess is about the same.

    George Bray, Aug 6, 2004
  6. George Bray

    George Bray Guest

    I've found out what most people with a medical background would
    already know - that human tears have a salt content of about 0.9%,
    which happens to be about the same as sea water. Perhaps one could use
    sea water as a cheap substitute for contact lens saline solution,
    followed by a long soak in hydrogen peroxide to kill any bugs.

    I also found that commercial table salt has other additives. These
    might not be very good for contact lens, so I will find a source of
    sodium chloride with a high level of purity. It should still work out
    cheaper than buying commercial saline solution.

    George Bray, Sep 6, 2004
  7. While the salt content of physiological (normal has a different meaning in
    chemistry) is indeed about 0.9%, The salt concentration in sea wter is much

    Commercial salt is fairly pure. Some additives are there by design. The
    crystallization process by itself will lead to purification.

    Repeating Rifle, Sep 6, 2004
  8. George Bray

    Dr. Leukoma Guest

    (George Bray) wrote in

    The parameters of the contact lens are determined in a state of equilibrium
    with 0.9% saline. Commercially available hydrogen peroxide does not
    contain sodium chloride. You would have to resoak your lenses in saline.

    Why not just fork over the money and buy the prepared sterile saline
    solution and give it up? You are playing with your eyes.

    Dr. Leukoma, Sep 6, 2004
  9. I really get upset by such statements. They are the equivalent of a robber's
    "Your money or your life." It is what keeps branded drugs still selling in
    the presence of incredibly cheaper generics. Now, if you don't know what you
    are doing then pay exxtra for the expertise. The questioner obviously had no

    Repeating Rifle, Sep 6, 2004
  10. George Bray

    Dr. Leukoma Guest

    Sorry to upset your precarious equilibrium, Mr. Bill. Unfortunately, I
    have to treat patients who contract acanthamoeba keratitis from such
    contaminated sources.

    Dr. Leukoma, Sep 7, 2004
  11. I was not suggesting that people who have no clue do their own thing. It is
    just that I do get upset at being talked down to. I do get upset with a
    charge of many dollars for small amount of physiologic saline solution when
    most of the cost is in the packaging. Because it is a considerable amount of
    trouble to prepare it, I am happy to buy it--but at the 99¢ store.

    Repeating Rifle, Sep 7, 2004
  12. George Bray

    Dr. Leukoma Guest

    Don't forget the added costs of manufacturing in a highly regulated FDA
    environment. I'm a chemist, and I certainly know how to make normal
    saline. I am also knowledgeable enough in microbiology to know that spores
    are difficult to kill, even with boiling. Did you know that it takes
    several hours of exposure to 3% hydrogen peroxide to kill acanthamoeba
    spores? To me, it isn't worth the risk, and I buy my saline just like
    everybody else.

    Dr. Leukoma, Sep 7, 2004
  13. George Bray

    George Bray Guest

    Dr G

    Thank you for your inputs. I respect your views, and know you're right
    even if I decide to take a calculated risk with my own eyes.

    Many eye care professionals encourage their patients to have laser eye
    surgery, and I think that's 1000 times more risky than what I'm

    1. Prepare a 0.9% saline solution from de-ionised car battery water
    which can be left hanging around under the kitchen sink for years. It
    may have lots of bugs but I'll get rid of some of those by boiling the
    water for 10 minutes in a saucepan with the lid on, before adding
    relatively pure sodium chloride.

    2. Use the DIY saline with a protein removal tablet. I need to do
    this so infrequently, that I would end up buying a new bottle of
    saline every time - a waste of money.

    3. Leave the lens to soak in 'stage 1' 3% hydrogen peroxide solution
    for 8 or 9 hours, at least, and then neutralise.

    4. Put the cleaned and disinfected lens in my eye.

    On the other hand, perhaps I can avoid all this by dissolving the
    protein removal tablet in 'stage 1' 3% hydrogen peroxide solution, and
    avoid any need to use saline in the first place. Do the tablets work
    perfectly well in stage 1 solution do you know?

    George Bray, Sep 7, 2004
  14. George Bray

    Dan Abel Guest

    I don't get upset by these statements. The amount of money to be saved is
    nearly inconsequential, and the cost of treatment when something goes
    wrong is major. Most people do not need to wear contacts. Thus, I feel
    that most people who aren't willing to take the extra time, effort and
    money that contacts take, should stick to glasses.

    And the same people who don't know what they are doing, are often the same
    people who don't realize it.

    Many people who read this group (like me) are layfolks. A clear warning
    not to try to make your own contact lens solutions is appropriate, in my
    mind. Those who have the expertise can determine for themselves whether
    they wish to take this advice or not.
    Dan Abel, Sep 7, 2004
  15. IIRC, there are protein removal tablets that are designed
    for use in 3% H2O2. Not all will necessarily work because
    peroxide is a strong oxidizer and may react with the remover.

    -- Robert
    Robert Redelmeier, Sep 7, 2004
  16. I thought that the approach to tackling resistant spores was to encourage
    their initial growth and then zapping them with heat. Has this changed over
    the years?

    Repeating Rifle, Sep 7, 2004
  17. George Bray

    Dr. Leukoma Guest

    The cornea is a good culture medium. Then, when all of the spores have
    converted into trophozites, a transplant is performed.

    Dr. Leukoma, Sep 7, 2004
  18. George Bray

    Dr. Leukoma Guest

    (George Bray) wrote in
    Let me point out the problems with this scenario. First of all,
    acanthamoeba spores have been found in both deionized as well as distilled
    water commercially available. I haven't researched this lately, but
    boiling the water for 10 minutes probably will not be sufficient. You may
    have to autoclave it, i.e. use a pressure cooker. YOU NEED TO FIND THIS

    Then - and I think you have already spotted the next logical flaw - what is
    the purpose of the saline if you are going to subsequently soak your lenses
    in 3% hydrogen peroxide? How will you remove the peroxide before inserting
    the lenses into your eyes without compromising the sterility?

    My recommendation is that you purchase commercially available sterile
    saline. Normal saline has many applications in medicine, including
    respiratory therapy. There may be more cost-effective alternatives if you
    purchase in bulk.

    Dr. Leukoma, Sep 9, 2004
  19. George Bray

    George Bray Guest

    Thank yor for your latest suggestions and sound warnings.

    The only purpose of the saline is to dissolve the protein removal
    tablets, as I thought saline is the best solvent for the tablets. If
    commercial 3% hydrogen peroxide solution is just as good, then I could
    use that and will not need any saline. But is hydrogen peroxide
    solution just as good for the protein removal tablets?

    You ask how I will remove the peroxide before inserting the lenses
    into my eyes, without compromising the sterility?

    I assumed that after 9 hours soaking in the peroxide, I am at exactly
    the same stage in a cleaning/disinfection cycle as anyone using
    2-stage peroxide based systems. After removal from the peroxide, I
    will place the lens in neutralising solution for at least 10 minutes,
    before placing the lens in my eye.

    George Bray, Sep 9, 2004
  20. George Bray

    Dan Abel Guest

    You'll have to read the directions on everything to find out how they
    work. I have used two different kinds of protein removal tablets. The
    first kind came with little plastic cups and you dissolved the tablets in
    saline. The second kind went directly into the hydrogen peroxide
    disinfectant. If I remember, the second kind was easier to use but cost

    I buy all my stuff at Costco. It is quite cheap, considering how long it lasts.
    Dan Abel, Sep 9, 2004
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