Contact lens‐related corneal infection in Australia

Abstract

Microbial keratitis is a rare but potentially severe sight‐threatening condition, associated with societal burden, cost and morbidity. Compared with microbial keratitis without lens wear, the disease in contact lens wear is more common, occurs at an earlier age, has lower morbidity and is more often caused by Pseudomonas aeruginosa and Acanthamoeba spp. Resistance to common antibiotics is infrequent in contact lens‐related isolates and there is little evidence to suggest increasing bacterial resistance over time. There is some evidence for increased reporting of cases of Acanthamoeba keratitis internationally. The incidence of contact lens‐related microbial keratitis has remained stable over time. Rates vary with wear modality, with the lowest risk of severe disease in daily disposable and rigid gas permeable contact lens wear; however, there are limited studies in daily wear silicone hydrogel and in contemporary daily disposable contact lenses. Risk factors for contact lens‐related microbial keratitis can be either modifiable or non‐modifiable and interventions to reduce the risk of, or severity of disease may be prioritised based on the attributable risk. Key risk factors based on high attributable risk include any overnight wear, failing to wash and dry hands prior to handling lenses and poor storage case hygiene practice. The strong link between microbial keratitis and storage case hygiene and replacement suggests the relevance of microbial contamination of the storage case. Both risk factors and evidence‐based strategies for limiting storage case contamination are presented, including storage case cleaning protocols and antimicrobial storage cases; however, it is unclear if such interventions can ultimately limit the rate or severity of microbial keratitis in daily wear. Emerging challenges include understanding and limiting the risk of infection associated with decorative or cosmetic contact lens wear, particularly in Asia, and in understanding the safety of contact lens modalities for myopia control in a paediatric population

Key words:

• contact lens
• microbial keratitis
• microbiology
• risk factors

ACKNOWLEDGEMENTS

This article summarises a presentation given as part of the H Barry Collin Medal presented in 2018. This was an enormous honour for me particularly as an import to Australia! I would like to thank my nominees, Optometry Australia, Professor Nathan Efron and Professor Barry Collin for considering me for this award. I have been privileged to work with the many higher degree students who have all made huge contributions to this work as part of their projects and who remain valued collaborators. These include Lisa Keay, Katie Edwards, Matt Green, Nicole Carnt, Chris Lim, Yvonne Wu, Ananya Datta, Jaya Dantam, Memoona Arshad, Sue Kweon, Man Choy and Suchi Katiyar.

To those collaborators and mentors who have worked with me, thank you. I would like to mention Mark Willcox, whom I have worked with since 1993, John Dart, Geoff Woodward and Brien Holden. Thanks also to my collaborators in Australia, Ajay Kumar, Hua Zhu, Jackie Tan, Thomas Naduvilath, Paul Sanfilippo and Andrew Apel and those internationally, Jod Mehta, Cherry Radford and Darwin Minassian. I am indebted to the members of the steering committee for the studies on corneal infection in Australia, New Zealand and London comprising Brien Holden, Debbie Sweeney, Des Fonn, Dwight Cavanagh, Oliver Schein, Hugh Taylor, Garry Brian and John McNally, the steering committee of the Asia Cornea Society Infectious Keratitis Study led by Donald Tan and Jod Mehta. These studies would not have been possible without the support of the professional associations and practitioners and hospitals in Australia and New Zealand. There are many others not mentioned here who have also made significant contributions and I thank them also.

These studies were funded by the Institute for Eye Research (now Brien Holden Research Institute), the Cooperative Research Centre (CRC) for Eye Research and Technology and Vision CRC, University of New South Wales Sydney Goldstar Award, National Health and Medical Research Council fellowships/scholarships to LK and YW, the British Contact Lens Association and through our industry partners CIBA Vision, Alcon Laboratories and CooperVision.

Notes

a Scientia Professor Fiona Stapleton was awarded the H Barry Collin Research Medal in 2018. This paper is based on her award lecture presented at the Super Sunday meeting (hosted by Optometry New South Wales Australian Capital Territory) on 10 March 2019 in Sydney, Australia.