Dry Eye Syndrome: Symptoms, Causes, and Treatment
Dry eyes can come with unpleasant symptoms. You might get red and burning eyes, or feel as though there is foreign object in your eye.
There are several possible causes. Dry eyes may develop when the eyes do not produce enough tear fluid. But the composition of the fluid is also important, because this influences how well the tear film attaches to the ocular surface and how fast it evaporates.
The tear film has three vital functions: it keeps the ocular surface smooth, it contains anti-bacterial substances, and it supplies the cornea with oxygen and nutrients. Dry eyes can worsen over time and lead to inflammation, so they should be taken seriously.
Symptoms of Dry Eye Syndrome
In most cases, both eyes are affected by dry eye syndrome. However, depending on the cause, some people may have only one dry eye.
- Burning eyes
- Itchy eyes
- Painful eyes and eyelids
- Red eyes
- Foreign body sensation, like a grain of sand in the eye
- A feeling of pressure in the eye
- Swollen eyelids
- Eyes feeling tired rapidly
- Light sensitivity
- Stringy mucus around the eye, especially when waking up
- Blurred vision
- Watery eyes
Causes of Dry Eye Syndrome
Dry eyes develop when:
- Insufficient tear fluid is produced
- The fluid evaporates too quickly
- The tear film does not properly lubricate the ocular surface
Dry eyes tend to be caused by a combination of factors. Dry eyes can also cause a vicious cycle because the dryness leads to inflammation, which, in turn, causes dry eyes. Dry eyes consequently become worse over time, and symptoms amplify if they are left untreated.2
Some environmental factors can create the perfect conditions for dry eyes to develop because they increase the evaporation of the tear fluid or irritate the eyes, causing inflammation.3
- Dry air (because of air-conditioning or heating)
- Direct sunlight
- Cosmetics (such as face cream or make-up running into the eye)
- Long hours in front of a computer screen. The eye gets moistened with each blink. Your blink rate is highly individual, but the average is around 17 blinks per minute.4 When you stare at a computer screen, your blink rate may decrease to a few blinks per minute, and this triggers the development of dry eye syndrome.5
- Wearing contact lenses. Contact lenses interfere with the dispersion of tear fluid, and they can damage the lipid layer that protects against evaporation. This makes the tear fluid evaporate faster.6
- Medications: Some medications can cause dry eyes as a side effect. Examples are beta-blockers, neuroleptics, hormones (such as the contraceptive pill), antidepressants, and antihistamines.7
Physical factors can cause dry eyes in several ways. They may impact the amount of tear fluid your eye produces, or its composition. The tear film consists of three layers: a mucous (mucin) layer, a liquid (aqueous) layer, and a lipid (oil) layer.
- Insufficient tear fluid production. Some people don’t produce enough tear fluid. It typically affects the liquid layer of the tear film. This is rarely the only cause of dry eye disease.8
- Disruption of the lipid layer. Dry eyes are mostly caused by a faster evaporation rate of the tear fluid,9 often because of a problem with the lipid layer that protects against evaporation. This may be due to blepharitis (inflammation of the eyelids). The meibomian gland, located at the edge of the eyelid, produces the lipid layer. If the gland is inflamed, it does not produce sufficient oily secretions.
- Decreased mucus production. Problems with the mucous layer are rather rare. This layer is essential for the tear fluid to properly lubricate the eye.
Other Possible Causes of Dry Eyes:
- Eyelids do not close completely. The eyelids help to keep the eyes hydrated. When they do not close completely, the cornea can become dry.1
- Certain diseases. Some conditions increase the risk of dry eye syndrome, such as rheumatic conditions, diabetes, hypothyroidism, inflammatory vascular diseases, and autoimmune diseases.10,11,12
- Changes in hormonal status. Hormonal changes, for example during pregnancy or the menopause, can promote dry eyes.13
- Poor and uncorrected eyesight. People who don’t have perfect eyesight tend to stare and blink less.14 This leads to an insufficient moistening of the eye.
- Age. Tear fluid production decreases with age.15 Older people also tend to take medications that can promote the development of dry eyes.
- Vitamin A deficiency. Vitamin A is vital for eye function and health. A deficiency can cause dry eyes.16
- Refractive eye surgery. Many people have dry eyes after undergoing refractive eye surgery. This is usually temporary, but in some cases it can be permanent.17
Treatment of Dry Eyes
Dry eyes cause inflammation that can, in the long-term, harm the eyes. You should therefore aim to get treatment for your dry eyes, especially if you’ve experienced the symptoms for a while.
Eye drops are usually the first treatment that comes to mind when you have dry eyes. They moisten the eye and can quickly relieve the symptoms.18,19 People with meibomian gland dysfunction should choose a lipid-containing product to stabilize the lipid layer of the tear film.20
How well eye drops work differs among people, and there are many different kinds available. Because they contain a diverse range of ingredients that each affect the different layers of the tear film, it may help to try several products to find the one that works for you.
Since inflammation promotes dry eyes, inhibiting the inflammatory response can be an efficient therapeutic approach for the treatment of dry eyes. It helps to break the vicious cycle of inflammation and dryness.
Heat Treatment and Lid Hygiene
In addition to heat treatment, practicing good lid hygiene is recommended. Regular cleaning of the eyelids helps to remove oily excretions from the lid margin, which helps to prevent and manage inflammation.26
Improving Environmental Factors
You can use air humidifiers to increase the humidity of the air, particularly in air-conditioned or heated spaces.
Try to avoid fumes as much as possible.
Wearing sunglasses can protect your eyes from sunlight and from wind.
If your dry eyes are caused by using your computer for long hours every day, you may benefit from using a software that measures eyelid movements and actively increases your blink rate.
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