NEW YORK (GenomeWeb) – Contact lens use appears to convert the microbiome of the eye into a microbial community that more closely resembles that found on the wearer's skin, according to a study published online today in mBio.
Researchers from New York University used 16S ribosomal RNA gene sequencing to profile eye swab and under-the-eye skin samples collected three times over six weeks in nine contact lens wearers and 11 non-contact lens-wearing controls. In those individuals — and in dozens more subjects who were not sampled over time — the team uncovered eye microbiome differences that corresponded with contact lens use.
The team has not yet parsed the reason for the more skin-like microbiome in the eye of contact lens wearers, though it suspects such changes might help in unraveling the increased risk of giant papillary conjunctivitis, keratitis, or other infections that have been described in contact lens wearers.
"Our study has the potential to help future studies explore novel insights into a possible role of the microbiome in the increased risk for eye infections in contact lens wearers," senior author Maria Gloria Dominguez-Bello, a translational medicine researcher at New York University, said in a statement. "When we can better understand the mechanisms, we will be able to test hypotheses and propose preventive measurements."
Dominguez-Bello and colleagues turned to 16S rRNA sequencing to get a culture-free look at microbial community members in skin, eye conjunctiva, and contact lens samples, if applicable, in 58 individuals.
The group included nine contact lens wearers and 11 controls who were tested biweekly over six weeks along with 28 individuals tested at a single time point, producing a total of 250 samples.
When they sorted through millions of sequences generated using pooled 16S rRNA amplicon sequencing on the Illumina MiSeq instrument, the researchers found that microbial community diversity was higher in eye samples collected without anesthetic eye drops, which were used as part of many ophthalmologic exam-based sampling efforts.
While the team did not see comparable diversity differences between individuals with or without contact lenses, it did see a shift toward more skin-like eye microbiomes in the contact lens wearers.
For example, eye samples from contact lens wearers had lower-than-usual representation by Haemophilus, Streptococcus, Staphylococcus, and Corynebacterium bacteria in eye samples from individuals who wear contact lenses.
Those changes were coupled with higher eye levels of Acinetobacter, Methylobacterium, Pseudomonas, or Lactobacillus bacteria — genera more typically found on the skin. A subset of species from those genera have been implicated in opportunistic infections, including conjunctivitis and keratitis, the study's authors noted, though it remains to be seen why the eye microbiome changes in contact lens wearers and the role that this has in infection, if any.
"Further research is required to determine if the risk is related to contaminating the lenses with bacteria from the skin of the finger or if contact lenses exert selective pressures on the eye bacterial community in favor of skin bacteria," they concluded.