I read Professor Henriquez piece in the Optician magazine ‘Bacterial keratitis; cause and consequences’ with great interest as it is clearly imperative that all practitioners and practice staff involved in contact lens fittings are fully aware of the consequences of poor compliance which, apart from the risk of permanent visual loss, results in a further pressure on overstretched hospital eye departments.
The article mentions the three most widely cited potential bacterial contaminant sources namely tap water, swimming and showers. However, even after careful hand washing the risk of posterior surface contamination from the fingers is another possible contaminating source and there is evidence this risk source may well be a greater risk because hand washing is nowhere nearly as effective as we like to think.
I first became aware of the limitations of hand washing in conversations with Professor Brian Meakin at the University of Bath Pharmacology Department who many UK practitioners may remember lectured extensively on the topic of microbial risks associated with contact lens wear in the 80s and 90s.
Simon Kilvington also showed how ineffective hand washing can be in his presentation at the 2014 BCLA conference in Birmingham1 and apparently it is common knowledge among microbiologists and pharmacologists that although hand washing removes grease, grime and general grubbiness, with the exception of the alcohol based formulations used in hospitals there is actually an increased microbial load after hand washing.
It is for this reason that we have suggested a safer way to access lenses is to use a ‘tap and tip’ method to pour the lens from the blister pack or case into the palm of the hand to avoid touching the posterior lens surface and thereby minimise the risk of microbial contamination.2
Unfortunately many contact lens manufacturers’ literature still shows removal from cases and blister packs using a finger placed into the back lens surface but hopefully an increased awareness of this practice will result in changed instructions.
1 Kilvington S Bacteria Biofilms Provide Protection from Disinfection by Multipurpose Contact Lens Care Solutions BCLA Conference , Birmingham 2014
2 Killpartrick M, Disposable lens risk factors and posterior surface contamination, Contact Lens & Anterior Eye, October 2016 39:5 p400