Swimming around in a pool of Acanthamoeba

I am a keen swimmer.  Over the past few years swimming has gradually become my main form of exercise. I wear goggles, I wear contact lenses, and when I occasionally forget either one or both, I usually muddle on and get some quality exercise all the same.

Between us, my family makes a combined number of over 8 visits a week to the local pool.  Whereas I have always struggled to swim well without goggles, I have actively encouraged my children to learn to swim without them.  But on an increasing number of occasions, I have had them both in tears on the journey home, and not just because I have denied them a treat from the sweet machine, but due to the fact that their eyes have been stinging so badly .  On a couple of occasions lately, this has been accompanied by a redness has lasted for several hours or even into the next day. 

Our local pool is not the healthiest of places to learn to swim.  In fact it is often quite filthy, but like a good parent, I cannot deny them their favourite pastime.  However, after a spell of persistent and unrelenting verrucas which have plagued our family’s feet for what seems like months, I wondered why I was not being more vigilant about their eyes as I was about their feet.  Furthermore, given the effect chlorine had has upon my hair and skin, what on earth is it doing to our eyes?

As practitioners, we are all aware of the devastating effects of Acanthamoeba keratitis.   But how often do we ask our patients during fitting sessions or aftercare appointments if they are regular swimmers?  I have no doubt that a large number of practitioners do, but I also think there are just as many who do not.

Acanthamoeba is found in our chlorinated swimming pools and hot tubs. In fact it has been found in almost every environment, from soil and dust, to fresh water, tap water, seawater and even bottled water (BCLA)  But despite its prevalence, Acanthamoeba keratitis is rare and occurs almost exclusively in contact lens wearers, with approximately one in 30,000 contact lens wearers with around 85% of cases the condition being associated with contact lens use (BCLA).

Acanthamoeba can reach the eye directly from a water source, or indirectly by introduction of it into a lens case when a lens, contaminated by the water source such as that found in the swimming pool, is not cleaned properly.  (BCLA) The organism is then transferred from the case to the eye on the contact lens. The lens holds the organisms in place on the cornea, which potentially could lead to an infection (BCLA)

Risk factors for infection in contact lens wearers are (BCLA)

Use of tap water during lens care
Use of ineffective lens care solutions
Failure to follow lens care instructions

And, of course,

Wearing lenses while swimming

The advice we give our patients is to wear good fitting goggles, but any swimmer knows that goggles do eventually steam up, and to clear them, we will wash them in the water.  Thus it is inevitable that water gets inside the goggle.  Secondly, our advice should be that wearers should dispose of their lenses immediately upon leaving the pool.  But how many actually do this?  Given that I have never observed this in the changing room, I suspect this number is few.

Despite wearing disposable lenses myself, I have often found myself wearing lenses to the end of a day despite an early morning swim, clearly increasing my chance of infection.  But when I am battling with two boisterous children to get home from the pool in time for lunch, the last thing I will remember is to remove my lenses and find my specs, which are almost always still in their case at home.

Perhaps I am not the best advertisement, but as a parent and lens wearer I am not in the minority. 

If the disease is recognised early, when only the surface layer of the cornea is infected, it may respond rapidly to treatment. However, if the disease is recognised late then intensive treatment may be needed for up to 12 months. Infection can also reoccur after treatment.

So what should we really be saying to our patients?  As most cases of Acanthamoeba keratitis are preventable if lens wearers follow our instructions on lens hygiene and lens care products, should we be supplying extra pairs of lenses for swimming, to encourage immediate disposal following their exit from the pool? 

Somehow I wonder what the compliance on that would be?
References:

http://www.bcla.org.uk/acanthamoeba.asp

http://www.revoptom.com/handbook/oct02_sec3_2.htm