Dry eyes

and Eva Rudolf-Müller, doctor

Dr. Andrea Bannert has been with since 2013. The doctor of biology and medicine editor initially carried out research in microbiology and is the team's expert on the tiny things: bacteria, viruses, molecules and genes. She also works as a freelancer for Bayerischer Rundfunk and various science magazines and writes fantasy novels and children's stories.

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Eva Rudolf-Müller is a freelance writer in the medical team. She studied human medicine and newspaper sciences and has repeatedly worked in both areas - as a doctor in the clinic, as a reviewer, and as a medical journalist for various specialist journals. She is currently working in online journalism, where a wide range of medicine is offered to everyone.

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Dry eyes occur when too little tear fluid is produced or when it evaporates too much. Affected people have red and / or burning eyes. Some also report a foreign body sensation in the eye. In addition to contact lenses and dry heating air, diseases such as diabetes can also cause dry eyes. Read more about the causes of dry eyes and what you and your doctor can do about it.

Brief overview

• Description: In dry eyes, the surface of the eye is not moistened with enough tear fluid because either too little tear fluid is produced or the tear film evaporates more intensely.
• Signs: reddened, itchy, burning eyes, sensation of foreign bodies in the eye, increased tears in the eyes, possibly a feeling of pressure and pain in the eye
• Causes and risk factors: e.g. staring at the computer or television screen for too long, dry room air, wearing contact lenses for too long, tobacco smoke, car exhaust fumes, air conditioning, drafts, old age, female gender, diseases (such as conjunctivitis, diabetes, thyroid diseases, autoimmune diseases), Medication
• When to the doctor Dry eyes should always be clarified by an ophthalmologist. It may be due to an illness that requires treatment.
• Medical treatment: Therapy of underlying diseases, use of "artificial tears", possibly medication containing cortisone
• What you can do yourself: Avoid drafts and tobacco smoke, ensure sufficient humidity in rooms, ventilate regularly, do not wear contact lenses for too long, take regular breaks when working on the PC, drink enough, etc.

Dry eyes: description

Dry eyes (medical: keratoconjunctivitis sicca, sicca syndrome) occur when the surface of the eye is no longer adequately wetted with tear fluid. The tear film usually ensures that the surface of the eyeball remains smooth and supple and enables clear vision. It also contains germicidal substances and thus protects against infections. It also supplies the transparent cornea with oxygen and nutrients, because it does not have its own blood vessels.

There is not enough tear fluid in dry eyes. It then feels like you have a grain of sand in your eye. In addition, there is an increased feeling of dryness, which is expressed by burning and itching eyes. In addition, red eyes often appear. The eyes often tire quickly, for example when working on a screen. They are also very sensitive to light.

With dry eyes, a feeling of pressure can also arise in the eye. In rare cases, dry eyes hurt.

Paradoxically, more tears can be observed in dry eyes: Due to the constant irritation, even minor influences such as a light wind can cause tears in the eyes. This can lead to blurred vision.

Other secondary symptoms are swollen eyes and secretion of mucus (those affected have sticky eyelids, especially in the morning).

The symptom “dry eyes” is relatively common: around a fifth of all people suffer from it. Usually both eyes are affected. However, some sufferers only have a single dry eye.

Dry eyes: causes and risk factors

A wetting disorder of the surface of the eye - i.e. the cornea and conjunctiva as well as the inner side of the eyelid - can be triggered either by reduced tear production or increased evaporation of the tear film (for example by a change in the tear composition). The tear film consists of several layers and contains an aqueous and a fatty phase. The latter stabilizes the film by protecting it from evaporation.

External influences

The most common cause of dry eyes are external influences. We blink less often when working on the computer or while watching TV. Then the blinking frequency, which distributes the tear film evenly over the eye, can decrease from 10 to 15 times per minute to just one to two beats per minute. One also speaks of the office eye syndrome.

Tobacco smoke, car exhaust fumes and ozone in the atmosphere are also irritating to the eyes. Drafts, car fans, air conditioning and dry heating air increase the evaporation of the tear film. Wearing contact lenses with low oxygen permeability for too long also has a dehydrating and irritating effect. Injuries to the eyelids and eye operations can also result in sicca syndrome.

Biological causes

Tear production decreases with age. Older people are therefore more likely to suffer from dry eyes than younger people.

In addition, women are more at risk than men, because the female sex hormone estrogen can disrupt tear production. Hormone replacement therapy during menopause therefore increases the risk of dry eyes.

Diseases

Wetting disorders of the eyes also occur in connection with various diseases. These include, for example, diabetes (diabetes mellitus), diseases of the thyroid gland, chronic rheumatism and inflammatory vascular diseases.

Many immunological diseases are also associated with dry eyes. The reason: The conjunctiva, which produces part of the tear film, is involved in important immune functions in the body. For example, in the autoimmune disease Sjogren's syndrome, the formation of tear fluid is disturbed.

Conjunctivitis can also trigger dry eyes. If only the conjunctiva in one eye is inflamed, a single dry, red eye results, while the other eye is healthy.

Other triggers for sicca syndrome are viral infections and nerve damage. Since the surface of the eye corresponds evolutionarily to a transformed outer skin, various skin diseases also lead to dry eyes.

When children suffer from dry eyes, in most cases a disease is the cause.

Medication

Certain medications can interfere with the production of tears if they are taken over a long period of time. These include psychotropic drugs, sleeping pills, beta-blockers, hormone preparations and medication for allergies. Corticoids ("cortisone"), which are contained in eye drops and ointments for conjunctivitis, for example, also cause dry eyes.

Vitamin A deficiency

If the eyes are burning and dry, there may also be a vitamin A deficiency. One of the reasons for the insufficient supply of vitamins can be liver dysfunction.

Dry eyes: therapy

In most cases, dry eyes are treated with "artificial tears". Which of the numerous drop or gel preparations is helpful depends on the cause of the dry eyes: If tear production is too low, tear substitutes, which supplement the aqueous phase of the tear fluid, help. Fat-containing preparations are used to improve the quality of the tear film.

If dry eyes do not improve with "artificial tears", anti-inflammatory therapy with cortisone or cyclosporine eye drops may be necessary.

There are also invasive measures that can be taken to increase the amount of tear fluid. For example, you can obliterate the tear ducts or seal them with plastic stoppers.

If there is an underlying disease such as diabetes, treating it can also relieve the dry eyes.

Dry eyes: home remedies & tips

The following measures can help prevent dry eyes or relieve existing symptoms:

• Make sure there is enough moist, fresh air in the room. For example, use a humidifier and ventilate regularly.
• Avoid exposure to direct drafts from air conditioners to avoid stressed, red eyes. When driving a car, adjust the blower so that the jet of air is not directed at your eyes.
• When working on the computer, take short breaks regularly (preferably every hour), during which you do not look at the screen. It also helps to blink consciously, because staring at the monitor reduces the blinking frequency.
• Avoid staying in smoke-filled rooms.
• Do not wear contact lenses for too long at a time.
• Only use tear substitutes that do not contain preservatives. These can cause allergies and increase the dryness of the eyes.
• Do not use irritating cosmetic products near your eyes.
• Drinking a lot also prevents dry eyes. You should drink at least two liters of liquid (water, mineral water, tea, juice spritzers, etc.) every day.

Finally, one last tip: on the edges of the eyelids are glands (meibomian glands) that produce the fatty secretion that forms the upper, oily layer of the tear film. If you carefully clean the edges of the eyelids with warm water and then massage them gently (e.g. with a clean cotton swab), you can support the function of these glands. This can also help against dry eyes.

Dry eyes: when do you need to see a doctor?

The causes of dry eyes are very diverse, and it is often difficult to differentiate between external factors and causative diseases. The professional association of German ophthalmologists therefore recommends that you consult an ophthalmologist in any case if your eyes are dry.

With various examinations, the doctor can assess the amount of tears, the composition of the tear film, corneal surface, eyelid position and tear film. How to determine the cause of dry eyes:

• Schirmer test: With the help of a filter paper strip in the conjunctival sac, the doctor measures how much tear fluid the eye secretes.
• Measuring the tear open time: To do this, the doctor colors the tear film with a dye (fluorescein). With a specially equipped microscope (slit lamp) he can observe how long it takes for the tear film to tear open after a blink of an eye.
• Examination of the surface of the eye: Changes to the surface of the eye can also be diagnosed with the aid of the slit lamp.
• Tearscope: This optical device enables the oil content of the tear film to be assessed more precisely.
• Further examination: If necessary, blood tests will be done, for example to determine the hormone status or rheumatoid factors. A conjunctival swab shows whether there is conjunctivitis, which is responsible for dry eyes.

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