Reusable Contact Lens Use Raises Acanthamoeba Keratitis Risk

Reusable contact lens use is linked to significantly higher odds of Acanthamoeba keratitis (AK) compared with daily disposable (DD) contact lens use, according to a study published in Ophthalmology. DD lens wearers can reduce their infection risk with regular follow-up, and refraining from showering in their lenses, reusing lenses, and wearing lenses overnight, according to the report. 

Researchers recruited 83 patients with AK as a case group and another 122 patients as a control group using the Accident and Emergency Department of South-East England. Patients in the case group included daily wear (DW) reusable or DD lens users diagnosed with AK recruited retrospectively between January 2011 and February 2013, and prospectively thereafter until August 2014. Patients in the control group were DW reusable or DD contact lens users recruited prospectively between January 2014 and June 2015. The primary outcome measures were independent risk factors and population attributable risk percentage (PAR%) for AK. 

DD use was reported in 24% of the patients in the case group and 54% of patients in the control group. In the multivariable analysis adjusted for potential confounders, the risk of AK was significantly higher for DW reusable soft (odds ratio [OR] 3.49, 95% confidence limits [CI] 1.75-8.43 and rigid (OR 4.56, 95% CI 1.03-20.19), compared with DD. 

In the DD-using subset, modifiable risk factors associated with AK included less frequent professional follow-up visits (OR 10.12, 95% CI 5.01-20.46), showering while wearing lenses (OR 3.29, 95% CI 1.17-9.23), lens reuse (OR 5.41, 95% CI 1.55-18.89) and overnight wear (OR 3.93, 95% CI 1.15-13.46). 

The PAR% estimated that 30% to 62% of AK cases can be prevented by switching from reusable soft to DD lens use, according to the study. 

“AK risks are increased >3-fold in DW reusable lens users versus DD lens use,” according to the researchers. “AK risks for DD lens users can be minimized by adherence to safe use guidelines (no reuse, overnight wear, or contamination by water).” 

Study limitations included its retrospective nature, the limited sample size of AK cases, and potential bias because a higher percentage of tertiary referral cases were White British.