The eyelid is a thin, muscular fold of skin that forms the front border of the eye socket. It covers the eyeball immediately below, from above through the upper eyelid, and from below through the lower eyelid. Between the two eyelids is the eyelid crease, laterally (towards the nose and temple) the upper and lower eyelid meet and form the eyelid angle. In addition to muscle tissue, glandular and connective tissue is also found in the eyelid.
Function of the eyelid
The function of the eyelid is mainly to protect the eye underneath, as well as a constant moistening and cleaning. Through the occasional involuntary blinking, tear fluid is distributed through the eyelid to moisten the eyeball. The eyelid also provides protection against mechanical influences, such as insects or contact.
The blink (better known as blinking) is carried out in humans within 300 ms, or just under a third of a second. This fast reaction is necessary because the eye is very sensitive on the one hand, but on the other hand it is limited towards the back exclusively by bony structures – so it cannot move anywhere. The eyelid absorbs a part of the energy produced by blunt impacts (e.g. a blow to the eye) and absorbs and distributes it.
It is controversial why we close our eyelids when we sneeze. On the one hand, it is thought that the body wants to counteract the excessive pressure that occurs when sneezing in order to protect the eyes. On the other hand, it could also be a protective reaction of the body to prevent coughing up bacteria and viruses from re-entering the mucous membrane of the eye.
Glands of the eyelid
In the immediate vicinity of the eyelids are a number of glands, including the Zeis, Moll, and Meibom glands. They produce a sebum- to sweat-like fluid in different compositions, which protects the eyes from drying out. They often cause inflammation – their most famous representative is probably the barleycorn.
It is important not to express the pus contained in the barleycorn, as it could otherwise enter the brain via the venous system. This is also generally true for purulent processes in the so-called T-zone in the face. The therapy of choice is a disinfecting and/or antibiotic treatment.
Diseases of the eyelid
Diseases of the eyelid are common and can affect different areas: A movement disorder of the eyelids, in the form of drooping of the upper eyelid, is called “ptosis” in medicine. This is usually a disorder of the nerve conduction path that serves the eyelid lifter muscle. Another movement disorder is a constant unintentional and unpleasant twitching of the eyelid.
Although this phenomenon is usually perceived as very disturbing, it is harmless in the majority of cases and usually disappears on its own after hours or days. The causes can be stress, irritation of the eye by foreign bodies, alcohol consumption, sleep deprivation, or mineral (magnesium) deficiency. A delayed eyelid closure reflex is called Stellwag sign, and usually occurs in the course of hyperthyroidism (Graves’ disease).
In addition to movement disorders, there are also inflammatory and parasitic diseases that can affect the eyelid. These include abscesses, cysts and also tumours, such as basaliomas and melanomas (both originating from the skin), or haemangiomas (originating from the blood vessels in the eyelid). The hereditary disease Down’s disease (also Down’s syndrome, trisomy 21) is characterized by a wrinkle on the eyelid covering the nose.
As it is physiological in the Asian region – i.e. without any disease value – it is often referred to as a Mongolian wrinkle. A twitching of the eyelid usually has a harmless cause. Possible causes can be stress, inner restlessness or tension, tiredness or strain of the eyes, for example due to long hours working at the computer.
A magnesium deficiency can also be the cause of a muscle twitch. Furthermore, a foreign body in the eye, inflammation of the eyelid margin or conjunctivitis can also trigger the twitching. More rarely, serious infections, neurological diseases, multiple sclerosis or tumours are responsible for eyelid twitching.
The twitching is caused by an irritation of the facial nerve, which causes the muscles of the eyelid – the orbicularis oculi muscle and the superior palpebrae levator muscle – to tense and relax uncontrollably. As a therapeutic measure, the eyelid can first be gently massaged with the fingers. Careful rubbing with a warm washcloth over the closed eyelid can also help to relax the muscles again.
Another possibility is the use of gel-filled glasses, which can be bought in pharmacies or drugstores. These can be put on the closed eyes when they are warmed up, because the warmth can relax the muscles. Usually the twitching stops by itself.
However, if the twitching lasts longer than a week or occurs more frequently in the month, you should consult an eye doctor. If the twitching occurs together with symptoms such as loss of sensitivity and/or muscle paralysis in the face, as well as blurred speech or visual disturbances, an emergency doctor should definitely be called as there is a suspicion of a heart attack or stroke. Inflammation of the eyelids is also known as blepharitis.
The most common symptoms can be itchy, reddened, thickened, scaly eyelids, a foreign body sensation, concomitant conjunctivitis or even eyelash loss (madarosis) with growth of eyelashes-like hairs from the meibom glands (distichiasis). A frequent cause of eyelid inflammation is external factors such as smoke, dust or a dry room climate or endogenous factors such as hypersecretion of the eyelid gland, secretion congestion of the meibomian glands or increased sebum production (seborrhoea). Dandruff often develops on the eyelid.
As the inflammation creates favourable conditions for pathogens, it can lead to a superinfection, especially staphylococci. The first therapeutic measure should be eyelid care, in which the encrustation is soaked in warm water or lotions and then carefully removed with a cotton swab. One can also try to carefully squeeze the glands.
If the inflammation does not get better within a few days, you may have to switch to antibiotic eye drops or systemic antibiotics. An allergic reaction or dry eye can also cause the picture of an eyelid inflammation. Eczema is an inflammatory change of the skin, which, in addition to redness, often occurs with symptoms such as burning or itching.
The causes of eyelid eczema are manifold. Often, rubbing the eyes with the fingers rubs molecules or particles into the eye which can make the eczema worse. Possible causes are substances that can trigger an allergic reaction in the eyelid.
These include cosmetics and skin care products, mascara, hair care products that can get into the eye, but also contact lenses and contact lens care products. Fragrances in detergents, environmental allergens such as pollen, house dust mites or food or substances in jewellery such as nickel can also cause eyelid eczema. Eczema can also be a symptom of atopic dermatitis, also called neurodermatitis.
As a first therapy, suspicious substances should be avoided and a doctor should be consulted if the symptoms occur more frequently. Warts on the eyelid are usually harmless and do not need to be removed from a medical point of view. Nevertheless, one should go to a doctor if one notices a growth, because as a layman it is difficult to distinguish the good growths from the malignant ones.
Often the warts are pedunculated nipples, as they are also found on other parts of the body such as armpits or groin. The warts are caused by the proliferation of fibrocytes and are therefore also called firbomes. Surgical removal, if at all, is only justified for aesthetic reasons and does not promise any guarantee that the warts will not return. – Removal of warts
- Homeopathy for warts