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Contact lens case changes color to signal bacterial contamination
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SAN DIEGO — Researchers have developed a microbial sensing device that alerts contact lens wearers of unsafe levels of bacteria and to discard the lens. They presented their findings at ICAAC 2015.
“We have devised a real-time sensing device, embedded within a contact lens case, that is capable of signaling the presence of abnormal levels of live microorganisms,” Nishal Govindji-Bhatt, PhD, a postdoctoral research associate at the University of Manchester, said in a press release.
The microbiosensor uses a range of tetrazolium dyes that indicate the presence of pathogens such as Pseudomonas aeruginosa, Staphylococcus aureus, Serratia marcescens, Fusarium solani and Candida albicans.
Govindji-Bhatt and colleagues found that the most effective tetrazolium dye, commonly called MTT, caused the sensor to permanently change from yellow to purple within 8 hours after the bacterial level had reached over 1 million counts in 1 mL of solution. The same effect was observed for each organism tested. In addition, researchers said the color change was easy to distinguish with the naked eye, and that the device was not affected by contact lens solution.
Nearly all contact lens wearers who participated in a recent CDC online survey indicated behaviors that may increase their risk for eye infection. According to the researchers, contact lens cases should be kept clean and free from bacterial contamination with the use of disinfectants.
“If this cleaning regime is not followed regularly and correctly, contact lenses can become covered in bacteria and when put into the eye, it can cause severe eye infection and in rare cases, a loss of vision,” Govindji-Bhatt said in the release.
According to the researchers, the microbiosensor has potential as a research tool in clinical studies of microbial colonization of contact lenses, and represents a new approach to reducing eye infections, and by extension, antibiotic use. – by Will Offit
Reference:
Govindji-Bhatt N, et al. Abstract K-326. Presented at: Interscience Conference on Antimicrobial Agents and Chemotherapy; Sept. 17-21, 2015; San Diego.
Disclosure: Govindji-Bhatt reports no relevant financial disclosures.