Reader and Industry Forum

Fingers, Bugs, and Contact Lenses

BY MIKE KILLPARTRICK

Eye hospitals continue to report a significant cause of red-eye presentation associated with contact lens wear. This begs the following questions: Why is this? What are we doing wrong? and Is there anything we can do about it? It is not only bad for the individuals concerned, but also bad for the contact lens industry/profession as well as for overstretched hospital eye departments.

Numerous studies show that storage case biofilm contamination is likely to be a significant cause of complications (Larkin et al, 1990; Wilson et al, 1991; Kilvington et al, 2011; Stapleton et al, 2012; and others. Full list available at www.clspectrum.com/references.). Additionally, daily disposable (DD) lenses pose a significantly lower risk of serious visual loss than reusable lenses do (Dart et al, 2008). Worryingly, it also may well be that the disinfecting solutions we rely upon are not as effective as we think, particularly against some strains of Pseudomonas (Winstanley, 2014) upon which Acanthamoebae feed.

Logically, we would expect a lower risk of complications with DD lenses versus reusable lenses because there is no maintenance requirement, no storage case contamination possibility, and no potential chemical or preservative sensitivity issue.

Kilvington’s presentation at the 2014 British Contact Lens Association (BCLA) conference (Kilvington, 2015) showed yet again how nasty storage cases can be. We have found that even ones that look clean may not be because disclosing agents reveal biofilms invisible to the naked eye.

If lack of compliance can be minimized by eyecare practitioners (ECPs) making a much greater effort to repeat both verbal and written instruction at initial fitting and annual exams, then a strong case could be made that as a matter of upholding professional care standards, ECPs should always fit daily disposable lenses in preference to reusable lenses. This is especially true if the prescription permits, because one of the largest risks—the storage case—has been removed.

Avoiding Contact

However, there is one possible cause of complications, even with DD lenses, that may have been overlooked—back surface contamination either from fingers or eyelashes. Kilvington’s BCLA presentation showed little difference in microbial growth on agar plate hand imprints before and after careful hand washing, demonstrating how hand washing has remarkably little effect upon the microbial bioburden.

However, many manufacturers and practitioners continue to advise patients to remove lenses from the blister pack by placing the finger into the back of the lens, thereby trapping the transferred microbial bioburden between the lens and cornea; the smallest epithelial compromise may well explain many of the cases seen at eyecare practices.

We, therefore, promote a “tap-and-tip” method for accessing lenses, in which the lens is loosened by tapping the blister pack before tipping and pouring the lens into the palm of the hand, thereby avoiding any possibility of back surface finger contamination. Some flat contact lens packaging in use has been designed to address this problem. CLS

For references, please visit www.clspectrum.com/references and click on document #240.

Mr. Killpartrick is an optician with Ellis & Killpartrick, which has optical practices in Bath and Cheltenham, United Kingdom. He is also a council member of the BCLA.