According to a study published this week in the open-access journal of the American Society for Microbiology, mBio, contact lenses may alter the natural microbial community of the eyes.
Researchers at New York University School of Medicine performed a study involving 58 adult participants, and found that contact lenses make the eye microbiome more like that of the skin, with greater proportions of the skin bacteria Pseudomonas, Acinetobacter, Methylobacterium, and Lactobacillus and lesser proportions of Haemophilus, Streptococcus, Staphylococcus, and Corynebacterium.
While the results clearly show a change in the microbiome of the eye, it's not presently clear how or why that change takes place. Senior study author Maria Dominguez-Bello, PhD, an associate professor of medicine at the university said, "if these bacteria are transferred from the fingers to the lens and to the eye surface, or if the lenses exert selective pressures on the eye bacterial community in favor of skin bacteria."
Contact lenses have previously been linked to the increased risk of developing certain types of eye infections, such as giant papillary conjunctivitis and keratitis. Knowing the means by which the eye's microbiome changes and fosters these bacteria is important, and will help prevent people from suffering from these infections in the future.
The study used a laboratory technique called 16s rRNA sequencing, which allowed the comparison of bacterial communities of the surface of the eye with that of the skin. Of the 58 participants, both lens wearers and non-wearers were represented, and their eyes were sampled 3 times over the course of 6 weeks.
Approximately 100 million people worldwide wear contact lenses, according to statistics from the U.S. Food and Drug Administration.
As of now, it is still too soon to offer any advice to people who wear contacts. Dr. Dominguez-Bello added "Other studies have shown increased risks for eye infections in contact lens wearers, and this might relate to impacting the microbiome. When we can better understand the mechanisms, we will be able to test hypotheses and propose preventive measurements."