The study conducted by Mark D. P. Willcox, PhD, FAAO, and his colleagues included 119 contact lens wearers who were surveyed about their contact lens hygiene habits. The study participants also provided their used contact lens cases, which were sent to a lab for culture studies. The researchers then assessed the relationship between hygiene practices and contact lens case contamination.
As researchers expected, contamination rates were high, which is not unusual when studying contact lens cases. The study found 66 percent of contact lens cases tested positive for bacterial or fungal contamination, and in nearly 40 percent of the contaminated cases, multiple organisms were isolated.
Habits associated with contamination
Researchers determined that three specific hygiene habits were associated with higher levels of contamination in the contact lens cases:
• Not washing hands with soap and water before handling contact lenses
• Not air-drying the lens case
• Using mismatched lens cases and disinfecting solutions
The study found that patients who washed their hands with tap water only and those who didn’t wash their hands at all both had higher contamination levels than those who used soap and water. It also found the contamination levels were higher in the cases that were wet when received for testing. And finally, contamination was more likely when patients used cases and solutions from different manufacturers.
Keeping in line with previous the results of previous studies, Dr. Willcox’s study found lens wearers who had more than two years of wearing experience had higher levels of contamination than those who had worn them for less than two years.
“The contact lens case is the single most important potential reservoir for contact lens contamination leading to infection,” says Michael Ward, MMSc, FAAO, instructor in ophthalmology at Emory University School of Medicine, director of the Emory Contact Lens Service, and member of the CDC’s Contact Lenses Workgroup.
“If we’re able to culture an organism from a corneal ulcer, we’ll likely find the same organism living in the lens case. Taking care of the lens case is very important. This article further supports the lens wear and care instructions that we’ve been trying to disseminate via the CDC.”
Optometry Times Editorial Advisory Board member Joseph Shovlin, OD, FAAO, DPNAP, says that the study shows the benefits of proper hygiene and the importance of washing with soap and water.
“I suspect the mechanical rubbing with soap with generous rinsing has its benefit in removing potential microbial load,” he says. “As far as the contact lens storage case is concerned, I find it stunning what we track from the case and to lens, and eventually to the eye. And, what is found in the case often correlates nicely to the pathogens responsible for inflammatory, and sometimes even dreaded infectious events.”
Dr. Shovlin says the message from the CDC’s initiative on healthy contact lens practices-Healthy Contact Lens Wear and Care-will help educate consumers, patients, and eyecare practitioners on best practices.
“We must educate patients on how their behavior reduces risk, increases their success and following our recommendations are important,” says Glenda Secor, OD, FAAO, immediate past chair of the AOA’s Contact Lens & Cornea Section.
Dr. Secor says that while ODs often remind their patients to wash their hands long enough to sing “Happy Birthday,” that may not be enough. Instead, lead by example, she says.
“Reinforcing by washing our hands in front of patients prior to every encounter is a subtle way to remind patients they can reduce their infection rate and possibly reduce just getting sick in general with proper hand hygiene,” says Dr. Secor.