There are plenty of people wearing contact lenses now and they know just how important it is to clean and store their contacts properly. Now, researchers have developed a one-step process that will coat the lenses with an antimicrobial film. With over 140 million contact lens wearers worldwide, researchers are hoping that with this new coating, it could dramatically reduce the risk of irritation to the eyes or even serious eye infections.
Mark D. Willcox of the University of New South Wales, Australia, said: “Microorganisms such as bacteria and fungi that grow on the surface of contact lenses causes irritation in five out of 100 users every year.”
Willcox was not involved in the new study, but added: “One in 2,500 wearers, meanwhile, develops an infection that is difficult to treat and can lead to vision loss. Despite the availability of new contact lens materials and better cleaning solutions, the risks of these conditions have remained the same for the past two decades.”
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“Researchers have in recent years tried various antimicrobial coatings for contact lenses and lens cases. Silver coatings have been commonly studied, but the materials can leak out of the lens, and their antimicrobial effect fades over time,” says Yi Yan Yang of the Institute of Bioengineering & Nanotechnology in Singapore, and the coauthor of the new study,
“The coatings made of antimicrobial peptides such as melamine are promising, but the peptides are expensive to make and difficult to coat on a lens surface,” she added.
Yang and James L. Hedrick of the IBM Almaden Research Center, California, along with their colleagues, have made an invisible antimicrobial coating that is applied by simply dipping a previously cleaned lens into the solution that contains the four different components: branched polyethylenimine (bPEI), catechol, polyethylene glycol (PEG), and urea.
The bPEI acts as a polymer scaffold that’s functionalized by the other components: Catechol helps the resulting coating stick to the lens surface, PEG suppresses the adhesion of microorganisms and is known to keep surfaces from fouling with proteins, and urea repels water and enhances PEG’s antimicrobial activity. After dipping the lens in the solution, the researchers sterilize it in an autoclave at 121°C, according to Chemical & Engineering News.
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In a study that was published in ACS, it said that they found the coating stayed on the lens for up to seven days, which kept various eye-infection-causing bacteria and fungi from growing on the surface. The coating also kept the proteins commonly found in tears from depositing on the lens, and had not caused any toxic effects on human cornea cells when a coated lens was placed directly on top of a cell culture over a 24-hour period.
“The coating could be easily applied to daily and weekly disposable contact lenses available today,” Yang says,
‘and the one-step coating method could be integrated into the current lens manufacturing process.’
Willcox said: “Manufacturers prefer as few steps as possible to coat lenses so as not to increase the cost of production and all contact lenses are sterilized by autoclaving.”
If it is worked into the manufacturing of the lenses, this could be a huge step for people who rely on them for everyday use.