What is the dry eye syndrome?

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Dry eye syndrome is a disease caused by a disorder of the tear film, either due to a deficiency in tear production (aqueous-deficient) or due to excessive evaporation (evaporative) that consists of inflammation of the eye surface and neurosensory changes that lead to eye discomforts.  It is an under-diagnosed disease as patients with mild dry eye do not go to a specialist. It is estimated that there are around 100 million people worldwide affected by this disease.

Dry Eye Syndrome explained in first person

Professionals and patients explain how you live with the disease
It is a chronic disorder that is going to need treatment, depending on the severity, this treatment will be more or less thorough. When the treatment is sufficient and adequate, the patient will not have any symptoms.
I knew at the start that it was going to be so hard, but the treatment works. It’s true that it’s long-term, and that you need to give it a chance and be very consistent and not stop, not even for one day, but it works. To the point that you can return to a pretty normal life.

Dry eye is a multifactorial disease noted for alterations in the tear film that cause eye discomforts and changes in vision. This disease is accompanied by an increase in osmolality (total concentration, measurement is osmoles per litre, of a substance in a solution) of the tear film, inflammation of the eye surface and neurosensory changes.

Classification of Dry Eye Syndrome

Cracked dry eye with a crossed-out drop

Aqueous tear-deficient dry eye. Is produced due to a lack of tear production.

  • Primary or secondary Sjögren syndrome. Primary Sjögren syndrome is a systemic disease that is noted for an autoimmune destruction of the exocrine glands of the whole body. The organs most affected are the eyes, the gastrointestinal system, the respiratory system, the skin, and the genitourinary system. It is diagnosed by the presence of dry eye combined with a dry mouth, by the presence of certain antibodies, a reduction in the salivary secretion and by the focal inflammation in a salivary gland biopsy. Secondary Sjögren syndrome has the same characteristics as primary Sjögren syndrome, but it is combined to the presence of another autoimmune disease such as rheumatoid arthritis, systemic lupus erythematosus, scleroderma, dermatomyositis, mixed connective tissue disease, Hashimoto’s thyroiditis, primary biliary cirrhosis, or autoimmune chronic hepatitis.
  • Without associated autoimmune disease. Due to an isolated lack of aqueous secretion of the tear gland, or as a secondary effect to other systemic medications such as anti-histamines, beta-blockers, antidepressants, tranquilisers, etc. 
Cracked dry eye with evaporated water

Evaporative dry eye. It appears due to the excessive loss of water of the exposed eye surface (due to evaporation).

  • Diseases of the Meibomian glands (rosacea, psoriasis, seborrheic dermatitis, etc.). The Meibomian glands found in the eyelid tarsi are the main source of the lipids of the tears.
  • Changes in the eyelids or the lacrimal aperture [Seventh cranial nerve paralysis, proptosis (forward displacement of the eyeball)] due to hyperthyroidism, low frequency of blinking, etc.
  • Vitamin A deficiency, interaction with topical medicine preservatives, changes due to contact lenses, allergic conjunctivitis.

Evaporative dry eye is more common than dry eye due to lack of aqueous secretion, although on many occasions both types are superimposed and there is simply a preponderance of one over the other.

How many people are affected by Dry Eye?

Dry eye syndrome is a very common disease, although in many casesunderdiagnosed. Its prevalence varies between 20% and 30% of the population, although it could rise to 33% in oriental populations. According to some estimates, around 100 million people worldwide have this disease. It is much more frequent in women, and increases with age.

Substantiated information by:

Maria Teresa Sáinz de la Maza Sierra

Published: 23 May 2019
Updated: 23 May 2019

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