Acanthamoeba keratitis risk greater with reusable vs. daily disposable contact lens use
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Key takeaways:
- The odds of developing Acanthamoeba keratitis were three times higher with reusable soft lenses vs. daily disposables.
- Daily disposable lens users can minimize risk by adhering to safe use guidelines.
The risk for Acanthamoeba keratitis increases threefold with reusable contact lens wear compared with daily disposable lens wear, highlighting the importance of safe use guidelines, according to research in Ophthalmology.
“The widespread use of [daily disposable (DD)] lenses is both because of convenience and because data suggest that the risk for severe microbial keratitis with vision loss, including that caused by Acanthamoeba, is probably reduced for DD compared with reusable contact lens wear, although this has not been confirmed for either predominantly bacterial or Acanthamoeba keratitis,” Nicole Carnt, PhD, associate professor and deputy director of research at the University of New South Wales School of Optometry and Vision Science in Australia, and colleagues wrote.
To better understand risk factors for Acanthamoeba keratitis (AK) in DD and daily wear (DW) reusable contact lens (CL) users, Carnt and colleagues conducted a case-control study of 83 AK cases and 122 controls from an accident and emergency department serving Southeast England. Researchers collected data via self-administered questionnaires.
According to results, 20 AK cases (24%) and 66 controls (54%) reported DD use. After adjusting for potential confounders, researchers reported the odds of AK were higher with DW reusable soft lenses (OR = 3.84) and gas-permeable lenses (OR = 4.56) compared with DD lenses.
In a subset analysis of DD users, AK was linked with less frequent follow-up visits with a lens professional (OR = 10.12), lens reuse (OR = 5.41), showering in lenses (OR = 3.29) and overnight lens wear (OR = 3.93), all of which were considered modifiable risk factors.
Researchers also reported that up to 62% of AK cases could be prevented by switching from reusable soft to DD lenses, according to population attributable risk percentage calculations.
“These results can be expected to encourage more CL users to switch from
reusable CLs, with their associated storage and solution risks, and to practice safer use of DD lenses (without reuse, overnight wear or contamination by water),” Carnt and colleagues concluded. “Safe CL use could be improved by the inclusion of clear risk avoidance data on lens packaging by manufacturers and advice in public swimming pools on water avoidance while using lenses.”
Perspective
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AK is visually devastating for patients and is associated with water contamination in contact lens wearers. Many soft DD, reusable and gas-permeable (GP) lens wearers report showering in lenses. Therefore, the evidence from this study showing the 3.3-fold increased risk for AK when wearing lenses while showering is of high significance for patient education.
This study also showed a 5.4-fold increased risk for AK with DD lens reuse along with a 3.93-fold increased risk with overnight lens wear. Sharing such findings with patients will stress the necessity for modifying AK risk factors.
Additionally, understanding that there’s a higher risk for AK with soft reusable and GP lenses than with DD lenses stresses the importance for clinicians to encourage patients to switch to DD lenses when appropriate to ensure the least AK risk possible.
Lastly, one of the study’s limitations is the small sample size of GP wearers, which necessitates further investigation.
Overall, this study provides valuable evidence for clinicians to educate patients on the modifiable AK risk factors (overnight wear, reuse and showering in lenses) associated with DD lenses along with encouraging DD wear over reusable soft and GP lens wear.
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