Why are tears important for our eyes?

Tears, also known as lacrimal fluid, is a substance which moistens the conjunctival and corneal surface of the eye as well as cleans it and protects it against germs. The secretion of tears in humans begins at the end of the first month of life. The main element of tears is water; however, tears also contain a small amount of salt (sodium chloride) and proteins, including bactericidal substances such as lysozyme or defensins. Tears are secreted by the lacrimal glands. Every time we blink, tears are spread out in a thin film all over the cornea in order to maintain an appropriate level of hydration in the eyes, help to heal wounds or provide protection against infections.

Lacrimal fluid of a healthy person forms a so-called tear film on the eye surface. This film consists of three layers:

1. lipid layer – an outer, oily layer which prevents excess tear evaporation and enables the tears to remain on the eye surface;
2. watery layer – a middle, widest layer whose role is to nourish the cornea and the conjunctiva;
3. mucous layer – an inner layer which helps to spread the watery layer all over the corneal surface in order to provide appropriate hydration level. 

When the eye is irritated, e.g. when an eyelash falls into it or when we are chopping an onion, lacrimal fluid is secreted so intensely that it does not manage to drain away through the lacrimal ducts, which is known as lacrimation. Tears moisten the surface of the eye and try to rinse out the foreign body (e.g. an eyelash stuck under the eyelid). They are also produced when we cry as a result of being driven by strong emotions, such as pain, sadness, happiness or agitation.

Some people complain of lacrimation disorders which may result from various diseases such as Sjögren’s syndrome (dry eye syndrome). The main symptom of the „dry eye” is usually a scratchy foreign body sensation in the eye. Other symptoms include a burning or itchy sensation in the eye, alternate dryness and excessive lacrimation periods, eye discharge, pain and bleariness. People complaining of the dry eye syndrome sometimes may also experience blurry vision or feel as if their eyelids were very heavy.

Other causes of lacrimation disorders may also be: keratitis, conjunctivitis, allergies and hypersensitivity to contact lenses or eye fatigue resulting from warm temperatures, smokiness, pollution or dry air. When you suffer from lacrimation disorders, it is recommended to apply so-called artificial tears into the eyes. These eye drops often contain sodium hyaluronate – a natural ingredient of the tear film, and they may also be used by contact lens wearers.

If you experience eye dryness or hypersensitivity, make an appointment for a specialist ophthalmologic examination during which you will have the general condition of your eyes tested and you will find out what the causes of your worrying symptoms might be. In order to make an appointment, call us on +48 605 03 66 30 or +48 506 807 111 or fill in a form in the CONTACT tab.

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