Microbial contamination of contact lenses (CLs) can lead to a host of corneal infections and inflammatory issues such as microbial keratitis, contact lens-induced acute red eye response (CLARE) and contact lens peripheral ulcers, to name a few. New research suggests antimicrobial peptide-coated CLs could reduce microbially driven corneal infiltrative events (CIEs) by at least 50% in extended wear lenses.
Still, the reduced infection rate didn’t reach statistical significance due to the low number of CIEs observed in individuals in the control group, who wore uncoated extended-wear biweekly disposables, the authors noted.
The investigation enrolled 176 participants who were either assigned to wear etafilcon A lenses with Mel4 antimicrobial coating in one eye and an uncoated control lens in the other eye or an extended-wear biweekly disposable modality. All subjects wore the lenses for three months.
After lens wear, nine participants (about 5%) experienced unilateral CIEs, six had CLARE, while three were diagnosed with infiltrative keratitis. Participants in the Mel4 coated lenses had between 50% and 69% fewer CIEs compared with individuals in the control group (0.4 events per 100 participant months; 1.7% vs. 1.3 events per 100 participant months; 3.4%).
Researchers also noted that all gram-negative bacteria (Citrobacter diversus, Acinetobacter haemolyticus and Acinetobacter lwoffii) isolated from lenses and lids of participants with CIEs were susceptible to the Mel4 peptide, with minimum inhibitory concentrations ranging from 15.6µg/mL to 62.5 µg/mL. Additionally, Mel4-coated lenses reduced bacterial adhesion from 2.1 to 2.2 log10 colony-forming units/lens.
The authors noted a few limitations of their investigation: First, the sample size was found to be insufficient given the low level of CIEs. Second, the study investigated the antimicrobial activity of a Mel4 coating on hydrogel etafilcon A lenses rather than silicone hydrogels.
“As approximately 50% of contact lens wearers worldwide use silicone hydrogel lenses, such lenses should be included in future studies,” researchers wrote in their paper.
Additionally, the contralateral study design may have resulted in subjects swapping lenses between eyes, the authors suggested.
Kalaiselvan P, Konda N, Pampi N, et al. Effect of antimicrobial contact lenses on corneal infiltrative events: A randomized clinical trial. Transl Vis Sci Technol. 2021;10(7):32.