Did you know that dirty pillowcases and sheets can lead to a serious eye disorder? Dry eye disease or dry eye syndrome, causes your eyes to not tear enough, which leads to inflammation and damage that can in turn lead to vision loss. The disease is chronic and progressive and impacts up to 70 million Americans. So what exactly is the connection between your bedding and dry eye, you may be wondering. The answer is demodex.
What Is Demodex?
Demodex mites are what is known as an ecto-parasites. They live in and on hair follicles and sebaceous glands. There are at least 65 known species of demodex, but only two (D. folliculorum and Demodex brevis) that live on people. They are found in 10% of all skin biopsies and 12% of all hair follicles sampled, but exist in up to 100% of older adults and those with certain conditions. (Source).
According to the National Institutes of Health:
Adult D. folliculorum mites are 0.3-0.4 mm in length and that of D. brevis are slightly shorter of 0.15-0.2 mm length… The eight legs of this mite move at a rate of 8-16 mm/h and this is mainly done during the night as bright light causes the mite to recede into its follicle. The body is covered with scales for anchoring itself in the hair follicle and the mite has pin-like mouth parts for eating skin cells, hormones, and oils (sebum) accumulating in the hair follicles.
D. folliculorum is more commonly localized to the face, while D. brevis is more commonly found on the neck and chest…. D. folliculorum is usually found in the upper canal of the pilo-sebaceous unit… and uses skin cells and sebum for nourishment. Several mites, with heads directed toward the fundus, usually occupy a single follicle. D. brevis, on the other hand, burrows deeper into the sebaceous glands and ducts and feeds on gland cells. Penetration of Demodex into the dermis or, more commonly, an increase in the number of mites in the pilo-sebaceous unit of > 5/sq cm, is believed to cause infestation, which triggers inflammation.
Female Demodex are somewhat shorter and rounder than males. Both male and female Demodex mites have a genital opening and fertilization is internal. Mating takes place in the follicle opening and eggs are laid inside the hair follicles or sebaceous glands. The six-legged larvae hatch after 3-4 days, and the larvae develop into adults in about 7 days. It has a 14-day life cycle. The total lifespan of a Demodex mite is several weeks. The dead mites decompose inside the hair follicles or sebaceous glands.
The number of Demodex mites present in the lesion increases with age. The prevalence of infestation with Demodex mites is highest in the 20-30 years age group, when the sebum secretion rate is at its highest. Older people are also more likely to carry the mites. Demodicosis is exceptionally seen in children aged <5 years. Presumably, Demodex passes to newborns through close physical contact after birth; however, due to low sebum production, infants and children lack significant Demodex colonization.
Infestation of both species is more common in males than in females, with males more heavily colonizing than females (23% vs 13%) and harboring more D. brevis than females (23% vs 9%).
The mites are transferred between hosts through contact of hair, eyebrows, and sebaceous glands on the nose.
Demodex and Dry Eye
The mites cannot live and reproduce without a host, but they can live for a brief period of time off of the human body and since they are active at night it is not impossible that they end up on pillowcases and sheets. The real issue, however, is not your bedding becoming infested with a mite population, though under some conditions the mites can live for a day and get back onto people at night. The bigger issue is the lack of sanitation that comes with having mites and bedding being loaded with extra dirt and bacteria. This can contribute to a night time environment that facilitates an optic health issue that leads to dry eye.
It is well established that demodex folliculorum and bacteria cause anterior blepharitis. This is a condition in which the eyes become red, irritated, painful, and crusty debris builds up on the eyes. Anterior blepharitis can lead to dry eye. Demodex brevis can also lead to dry eye, as it can clog the meibomian gland when it burrows in to feed. The gland produces the oil layer of tears which keeps them from evaporating.
Treating Dry Eye
Treating dry eye disease that is related to Demodex mites requires eliminating the Demodex mite population, alleviating the symptoms to relieve the eyes, and maintaining ocular hygiene to prevent further bacteria build up. This includes cleaning your bedding in hot water and drying it with the hottest possible dryer setting to kill mites. It also means using an effective eyelid cleanser, like Cliradex, which is specifically formulated to wipe away and kill Demodex mites. In fact, Cliradex, with its main component T4O, is the doctor recommended method to eliminate mites. Its formula will help relieve symptoms of dry eye.