This conclusion has been reached through scientists collecting thousands of bacteria recovered from people’s eyes and subjecting them to molecular biological testing. Through this testing, researchers isolated a varied set of microorganisms from the eyes of contact lens users. In total over 5,000 tests were performed. The differences noted could explain eye infection risks in relation to contact lens use.
Interestingly, the range of microbes recovered from the eyes of those who wear contact lenses was similar to the types of microorganisms recovered from the eyelids; furthermore, the microbes isolated were somewhat different to the microbes found in the eyes of people who do not wear contact lenses. This means that the microbiome of contact lens wearers more closely resembled the microbial composition of the skin.
The species found in higher numbers with contact lens wearers included the bacteria Methylobacterium, Lactobacillus, Acinetobacter, and Pseudomonas. Around 60 percent of the bacteria isolated were different for regular contact lens users.
The inference is that putting a foreign object into the eye, and one that is handled by people, changes the natural microbial composition of the eye. This can come about through the handling of the contact lens. Another factor, which the researchers speculate on, is that the act of applying pressure to the eye alters the localised immune system in the eye and this affects which microorganisms grow in higher numbers.
These results indicate that contact lens wearers can be prone to different types of eye infection compared with those who do not wear contact lenses. Furthermore, because microbiomes alter as people age, the microbial profile can alter — along with the risk — over time.
One of the reasons for this investigation was that the research group were curious to understand the relationship between corneal ulcers and the popularity of soft contact lenses; a trend that began in the early 1980s.
In terms of people protecting themselves, the researchers also recommend that good hand hygiene is practiced.
The research was undertaken at NYU Langone Medical Center. The research has been reported to the annual meeting of the American Society for Microbiology. The findings have yet to be published.