New antimicrobial materials may better prevent lens, case contamination

The University of New South Wales has been investigating the antimicrobial properties of fimbrolides, furanones and dihydropyrrolidones, and preliminary findings have been promising, according to a summary of a presentation made at the British Contact Lens Association conference.

Fimbrolides, furanones and dihydropyrrolidones are found in red seaweed native to the coast of Australia and New Zealand, the summary said. These components appear to interfere with the ability of the bacteria to communicate with each other, which subsequently reduces their ability to develop a biofilm.

Lenses made with covalently bound fimbrolides have resulted in a 50% to 90% reduction in bacterial binding, Mark Willcox explained during his presentation.

A short, small-scale clinical trial showed no difference in clinical response or comfort to control lenses that were not coated, suggesting that the additional antibacterial substance had no detrimental impact on the clinical performance of the lenses, according to the summary.

The University of New South Wales has also been working with cationic peptides, specifically melamine. These disrupt the bacterial membranes and resist autoclaving, confirming that they can be added to materials, which could still be easily sterilized post-manufacture, the summary said.

They are also active in tears and rich in proteases and peptidases, are unlikely to stimulate bacterial resistance and are relatively non-toxic. Adding them to the surface of contact lenses reduced binding of a broad spectrum of bacteria, including drug-resistant strains, Willcox explained.

The development of antimicrobial materials should reduce the rates of adverse events and has been shown to have little effect on the normal biota of the eye. Clinical trials being conducted now may lead to the commercialization of such materials in a few years, the summary said.