This article was written by Liz Ball and David Lunt, and originally published in Insight magazine.
“There are mites living on your face, they can poop and cause conditions like blepharitis”, or so recent media reports claim. It’s a bit of a revolting thought, especially considering that mites are related to spiders. But is it true? To find the facts, Liz Ball, Glaucoma UK’s Development Manager for northern England, spoke to David Lunt, a Consultant Ophthalmologist at South Tees Hospitals NHS Trust.
Tiny organisms, like bacteria and mites, are constantly moving in, out, through and around our bodies. Most of the tiny organisms living in and on us get on with their business without ever bothering us. We even rely on some of them to keep us healthy, like the good bacteria in our guts. Mites living on our skin help to keep it clean. But, if their population gets too dense or unbalanced, they can start to cause us harm. It’s thought that large or unbalanced populations of mites around the eyelids might cause blepharitis in some people. But there are lots of other causes of blepharitis, too.
Two types of mites, ‘Demodex folliculorum’ and ‘Demodex brevis’, commonly live around our eyelids and eyelashes. They’re often referred to together simply as Demodex mites. Demodex mites are so common that everyone over the age of 75 is thought to have them. They are tiny, cigar-shaped arachnoids, related to spiders, measuring up to 0.4mm. In small numbers, they might help to keep our eyelashes clean.
Given that Demodex mites are so common, their role in blepharitis is not fully understood. However, it’s thought that they might contribute to blepharitis in some people in a few different ways:
It’s thought that tea tree oil might slow or prevent Demodex mite reproduction. Therefore, wiping eyelids with a weak solution of tea tree oil might help. However, it’s unclear how effective this is.
There are lots of possible causes of blepharitis. Most treatments for blepharitis are the same, whatever the cause. Find out more about the condition and how to manage it in our leaflet titled ‘Blepharitis’.
Research published earlier this year found that ‘Demodex folliculorum’ mites are evolving to become increasingly dependent on us. For example, they’ve lost the genes that control their day-night cycle and instead rely on chemicals we produce to control it. Similarly, they’ve lost some genes related to reproduction. These changes mean that, over time, ‘Demodex folliculorum’ mites might become extinct.
Evolution happens slowly, so there’s little chance of ‘Demodex folliculorum’ mites becoming extinct yet. But, when they do die out, they’ll no longer help to clean our eyelashes for us. Plus, it will change the balance of tiny organisms living on our eyelids. At this time, we can’t be sure what that will mean.
This article was written by Liz Ball and David Lunt, and originally published in Insight magazine. “There are mites living on your face, they can poop and cause conditions like blepharitis”, or so recent media reports claim. It’s a bit of a revolting thought, especially considering that mites are related to spiders. But is it […]
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