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Posted 19/04/2018 13:14:48

This blog considers the connection between dry eye, blepharitis,meibomian gland dysfunction and the demodex mite.

Dry eyes are very common, particularly in the over seventies, who with medical advances are also becoming much more common.
Whilst dry eye is rarely sight threatening, its right up-there on par with acute angina in quality of life studies, so we need to take the condition seriously.
There is a link between tear quality, the underlying cause of most dry eyes and meibomian gland dysfunction which I have covered in previous articles.
This article concerns the demodex mite, seen above, which is found in significantly higher numbers in patients with meibomian gland dysfunction, in blepharitis and in acne rosacia.
Demodex mites are frightening little creatures when seen in high magnification and form part of the normal fauna and flora on all of us; they are around one third of an eye lash diameter in width and three time that in length. They are not visible with the human eye but may be seen in situ with a high magnification bio-microscope. ( I have just ordered one )
These mites live in the hair follicles and skin follicle on the face and lid margins and emerge at night to feed and breed. This is not necessarily a bad thing since they may well act as natures vacuum cleaners, getting rid of dead skin cells and waste products.
Indeed of the trillions of cells which make up the human body, only ten percent are human. (ref https://www.rosacea.org/patients/demodex) The rest are friendly symbiotic passengers, helping with digestion and fenDry eye, blepharitis, acne rosacea, demodex mites, is there a connection ?ding off the bad bugs. Because they are so small, they account for only about 1 to 2 percent of our body mass – about three to five pounds in weight, three bags of sugar.
There does, however, seem to be a definite link between higher than normal numbers of demodex and acne rosacea, dry eye and some eye lid conditions.

How to kill demodex mites.
These bugs are surprisingly difficult to kill, they seem to survive many disinfectants including 75 percent alcohol. Tea tree oil seems to be remarkably good at both causing the mites to emerge from hiding in pores and kill them. Wikipedia is rather scathing about the efficacy of this oil, however there has been much clinical research which seems to prove its efficacy (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1772908/) Tea tree oil is distilled from the leaves of the Melaleuca alternifolia plant, found in Australia. It is easily commercially available and relatively cheap. I would recommend using pure oil on the face daily if necessary, particularly for acne rosacea, or diluted if there is a reaction, which is rare.
Be careful around the eyes though, high concentrations will irritate, particularly in the eye.
You can get lid scrubs with tea tree oil in diluted form and also tea tree oil shampoo. Lid scrubs with more concentrated solutions is best performed here in the practice, it does achieve quicker results and should be performed on a weekly basis for about three weeks.