Ultimate survivor: Study finds bacterial strain endures common contact lens solution

Proper contact lens care is critical to warding off harmful eye infections, however new research finds one bacterial strain stubbornly defied a common disinfectant solution much longer than anticipated.

The findings out of Great Britain indicate a strain of Pseudomonas aeruginosa (P. aeruginosa)—a catalyst for microbial keratitis—displayed prolonged resiliency when immersed in a commonly used contact lens cleaning solution.  

This is just another opportunity for practitioners to educate their patients on the importance of proper lens care.

Scientists at the University of Liverpool, and The Royal Liverpool University and Broadgreen University Hospitals NHS Trust, compared the robustness of a lens cleanser developed with the reference strain P. aeruginosa 9027, to other strains of the bacterium taken from hospital patients across the U.K. The P. aeruginosa strain 9027 is described by researchers as the standard used in tests by makers of lens disinfectant solutions.  

While the majority of the other P. aeruginosa strains, including 9027, were neutralized by the cleansing agent within 10 minutes, P. aeruginosa strain 39016—linked with a severe, protracted case of keratitis—survived more than four hours longer than the reference strain.  

The research was presented at a medical meeting earlier in April.  

Keep 'em clean
Corneal infections can be a serious—albeit infrequent—complication with improper contact lens usage, and the British research underscores the important role optometrists can play in reinforcing appropriate contact lens safety habits with their patients.  

"The fact that it didn't kill the strain in four hours is not a death sentence because there are other aspects that are critical to reducing the risk of contact lens infections," says Glenda Secor, O.D., AOA Contact Lens and Cornea Section (CLCS) chair. "This is just another opportunity for practitioners to educate their patients on the importance of proper lens care and establishing a successful contact lens experience."

Microbial keratitis has an annual incidence of about 20 per 10,000 people using extended wear contact lenses, and about 4 per 10,000 people with daily-wear, according to the AOA's Care of the Contact Lens Patient reference guide for clinicians. But proper contact lens care can hedge risks.

Dr. Secor suggests reinforcing with patients the importance of good lens hygiene, such as cleaning contact lens cases and changing them out every 3 months, rubbing contact lenses and rinsing thoroughly before soaking lenses in solution overnight, replacing solutions daily, never using tap water on lenses and simply washing hands prior to handling lenses.  

"Compliance with the whole process is critical to success," Dr. Secor says.  

Patients might find additional resources at the AOA Contact Lens Safety Website.

April 24, 2014

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