Our eyes are equipped with lashes, brows and rapid reflexes to prevent foreign objects from entering them. Yet many people intentionally stick things in their eyes every day – such as contact lenses – and new research shows that it changes the bacterial communities living in their eyes.
Just as other parts of the body, such as the skin, gut and mouth, harbor particular communities of bacteria, so do the eyes. In the new findings – to be presented at the annual meeting of the American Society for Microbiology on May 31 – researchers suggest that contact lens wearers may be more prone to eye infections than nonwearers, because the lens disrupts the eye's normal balance of bacteria.
The researchers compared the strains of bacteria living in the eye to those living on the skin just beneath the eye.
"Since the tears contain antibacterial compounds, we were expecting low diversity [in the eye]," said lead investigator Hakdong Shin in an interview with Tech Times. "That the eye bacterial diversity is higher than that on the eye bag's skin was surprising."
The eyes of both contact lens wearers and nonwearers were found to be home to more than 5,000 distinct strains of bacteria. But the strains found on the eyes of contact lens wearers were more similar to the strains found on the skin of the strains in the eyes on nonwearers.
Bacteria typically found in the eye is likely help protect the eye from invaders, according to Shin, though he added that "we do not know for certain the function." Contact lens' wearers are well-known to suffer from more frequent eye infections, particularly corneal ulcers.
One common invader linked to such infections is a type of bacteria called Pseudomonas. Three times as many of these bacteria were found in the eyes of contact lens wearers, compared with those of nonwearers.
"This study suggests that because the offending organisms seem to emanate from the skin, greater attention should be directed to eyelid and hand hygiene to decrease the incidence of this serious occurrence," said study co-investigator Jack Dodick, M.D., in a press release.
It is "too early to give advice yet" on how contact lens wearers can avoid disrupting their eyes' microbial communities, said Shin. For now, it is safe to say: don't stick stuff in your eye if you can avoid it.
Photo: n4i | Flickr