Dry eye syndrome, or dry eye disease, occurs when the eyes do not make enough tears, or the tears evaporate too quickly because the oil glands are blocked or abnormal.
This leads to the eyes drying out and becoming inflamed (red and swollen) and irritated.
The condition is also known as dry eyes or keratoconjunctivitis sicca. If the main problem is a blockage of the oil-secreting glands, then the condition is called, meibomian gland dysfunction or lid margin disease.
Thecan be mild or severe. They include:
- dry or sore eyes
- blurred vision
- the feeling of something in your eye
See your doctor if you experience any of these symptoms. They may examine you for other conditions or may refer you to an optometrist for further tests. Read more about.
Dry eye syndrome can have a number of causes, including:
- being in a hot or windy climate
- certain chronic diseases
- side effects of medicines
- hormonal changes
- getting older (up to a third of people aged 65 or older may have dry eye syndrome)
Read more about the.
Treating dry eye syndrome
Dry eye syndrome is not usually a serious condition, unless it is due to inflammation or certain diseases where there is an overactive immune system. Steps can be taken to relieve the symptoms, including:
- treating the underlying cause
- using ocular lubricant eye drops
- wearing specialised eyewear
In severe cases, dry eye syndrome may be treated with surgery to block the drainage tear ducts. This is either with temporary plugs or by permanently sealing the drainage hole.
Read more about.
You can help ease or prevent dry eyes by:
- keeping your eyes and eyelids clean and protecting them from the environment
- using your computer or laptop correctly to avoid eye strain
- using a humidifier to moisten the air
- avoid air conditioning or sitting directly in front of a fire
- eating a healthy diet that includes flaxseed oil and omega-3 fats
Read more information about.
Who is affected?
Dry eye syndrome is a common condition. It tends to affect people above 60 years of age, but it can affect younger people. It is also more common in women than men.
Are there any complications?
Dry eye syndrome may be uncomfortable, but does not usually affect vision. In rare cases, severe untreated dry eye syndrome can cause scarring of the eye's surface, leading to visual impairment.
Contact your doctor or visit your nearest accident and emergency (A&E) department immediately if you have any of the following symptoms, as they could be a sign of a more serious condition:
- extreme sensitivity to light (photophobia)
- very red eyes
- very painful eyes
- a deterioration in your vision
Read more information about the.
For most people, symptoms of dry eye syndrome are mild. In more severe cases, it can become painful and lead to complications.
Symptoms usually affect both eyes and may include:
- feelings of dryness, grittiness or soreness which get worse throughout the day
- red eyes
- eyelids that stick together when you wake up
These symptoms may get worse in smoky or hot environments.
More severe symptoms include:
- extreme sensitivity to light (photophobia)
- very red eyes
- very painful eyes
- a deterioration in your vision
Severe symptoms can be a sign of complications such as scarring of your cornea (the transparent layer at the front of the eye).
Contact your doctor immediately if you have any of these symptoms. If this is not possible, visit your nearest accident and emergency (A&E) department.
If left untreated, complications from dry eye syndrome could affect your sight permanently.
Read more information about the.
Dry eye syndrome can have many different underlying causes. However, in many cases there is no single identifiable cause.
Dry eye syndrome can be caused by:
- the environment, particularly dry heat or a windy climate
- disease (see below)
- side effects of medicines
- hormonal changes
The importance of tears
You probably only notice your tears when you laugh or cry. However, the surface of your eye is always covered by a thin layer of liquid known as the tear film.
Your tears have several important functions. They lubricate your eyes, keeping them clean and free of dust, protect your eyes against infection, and aid sight by helping to stabilise your vision.
Where tears come from
Tears are produced and regulated by a system known as the lacrimal functional unit.
The lacrimal functional unit is made up of a number of different parts that work together. This is described below:
- lacrimal gland – found in the upper corner of the eye socket behind the bone and produces the watery liquid that makes up the majority of your tears
- goblet cells – found in the lining of the eye (conjunctiva) and produce a sticky mucin which allows the watery liquid part of the tear film to stick to the surface of the eye
- meibomian glands – found along the entire length of the upper and lower eyelids and produce a specialised oil that forms the outer layer of the tear film, preventing evaporation
- eyelid – spreads tears across the surface of your eye when you blink
- cornea – the clear window at the front of your eye which is vital for sight
- conjunctiva – a clear membrane that lines the back surface of the eyelid and forms a natural gutter between the eyelid and the eyeball
- tear ducts – two small drainage channels at the inner ends of the eyelids (next to the nose) that allow tears to drain into the nose through the tear duct openings
If any part of the lacrimal functional unit is affected, the whole system can break down, resulting in one of two outcomes, or possibly both:
- the quantity of tears is affected – either the lacrimal gland does not produce enough tears due to diseases damaging the glands, or the tears evaporate before the body has a chance to replace them
- the quality of the tears is affected – the tears contain abnormal proteins and other molecules that irritate or damage the surface of the eye
Either outcome can cause dry eye syndrome.
As the eyes are no longer adequately protected by the tear film, special signals are sent to the immune system (the body's defence system) to try to compensate and correct this deficiency. It is this process that causes the inflammation (redness and swelling) of the eye, which is frequently associated with more serious forms of dry eye syndrome.
Blepharitis and meibomian gland dysfunction (MGD)or meibomian gland dysfunction (MGD) is a common condition which affects many people with dry eye syndrome. It can occur at any age and in otherwise healthy people.
Blepharitis is an inflammation of the eyelids which blocks meibomian (oil-secreting) gland openings, sometimes resulting in a cyst.
As the oils cannot freely drain onto the tear film, they begin to stagnate in the glands. This causes the oil to solidify and change in the gland. The new oils cause irritation and inflammation when they drain onto the surface of the eye.
People with existing dry eye syndrome who get blepharitis will find their symptoms get worse and the severity of the condition increases.
The symptoms are burning and stinging along with crustiness of the eyelid and lashes. Blepharitis is not usually a serious problem, but if not treated properly it can cause severe inflammation of the cornea (transparent window of the eye), particularly when associated with medical conditions. This can cause permanent visual impairment.
Read more information about how blepharitis-related dry eye syndrome is treated.
A number of things can interfere with the lacrimal functional unit. These are explained in more detail below.
Hormones and the nervous system
Hormones (powerful chemicals produced by the body) and the nervous system (your nerves, brain and spinal cord) play an important part in tear production.
Hormones stimulate the production of tears. The changes in hormone levels that occur during the(when a woman's periods stop), pregnancy or while using the contraceptive pill may explain why older women are more susceptible to dry eye syndrome.
The nervous system can trigger an increase in tear production, often as a way of protecting your eyes from potentially harmful substances. This is why, for example, your eyes water if you are exposed to smoke. If you have a medical problem that causes changes in nerve function, this can also cause dry eye syndrome.
Environmental factors can have a drying effect on your eyes, causing your tears to evaporate. These include:
- dry climate
- hot blowing air
- high altitude
When you carry out an activity that requires visual concentration, such as reading, writing or working with a computer, you tend to blink less frequently. This can cause your tears to evaporate and lead to symptoms of dry eye syndrome.
Several medicines are thought to cause dry eye syndrome in some people. These include:
Laser refractive surgery
Some people who have had laser-assisted in-situ keratomileusis (LASIK) surgery find that they have dry eye syndrome in the weeks after surgery. The symptoms usually clear up after a few months, but in some cases may continue.
Sometimes, contact lenses irritate the eye and cause dry eye syndrome. Changing to a different type of lens, or limiting their use, usually helps resolve the symptoms.
Most people with dry eye syndrome also haveor meibomian gland dysfunction (MGD) (see above). Blepharitis can occur at any age, but can be associated with the following conditions:
- seborrhoeic dermatitis – a common skin condition that is often referred to as seborrhoeic eczema
- acne – a common yet poorly understood chronic (long-term) skin condition that mainly affects the face
Other medical conditions that can cause dry eye syndrome include:
- (eczema) – a condition that causes inflammation of the skin
- allergic conjunctivitis – inflammation of the conjunctiva (the transparent layer of cells that covers the white part of the eyeball and the inner surfaces of the eyelids) caused by an allergy
- Sjögren's syndrome – a condition that causes excessive dryness of the eyes, mouth and vagina
- – a condition that causes pain, swelling and inflammation in the joints and can affect any organ in the body
- – a condition where the immune system attacks healthy body tissue, particularly blood vessels
- scleroderma – a skin condition that can also affect the blood vessels
- previous trauma (serious injury) – such as burns or exposure to radiation
- – a reactivation of the virus, caused by the herpes varicella-zoster virus
- Bell's palsy – a condition that causes weakness or paralysis to the muscles of one side of the face
- – a virus that attacks the body's immune system
As you get older, you produce fewer tears. This, combined with the effects of the menopause, probably explains why dry eye syndrome is common among older women.
Your doctor should be able to diagnose dry eye syndrome by your symptoms and medical history. They may examine you to check for other conditions and complications.
Your doctor will also want to know about:
- any medicines that you are taking
- your social circumstances – for example, if you work on a computer all day
- whether you have any other symptoms (that may not be affecting your eyes)
These may help your doctor identify a possible cause of your dry eye syndrome.
Referral to an optometrist
You may be referred to an optometrist for a check-up. Optometrists are trained to recognise sight defects and eye conditions. Although your doctor may refer you to an optometrist, they are private practitioners and charge for their services.
Your optometrist can examine your eye and confirm whether you have dry eye syndrome and any other associated conditions and complications. They will also advise about treatment.
If the diagnosis is uncertain or specialist tests and treatment are needed, your doctor may refer you to an ophthalmologist. Ophthalmologists are surgeons who specialise in eye conditions. Like optometrists, they use special equipment and techniques to examine the eye.
Tests carried out to assess the quality and quantity of tears are described below.
Flourescein dye test
A special yellow-orange dye in eye drop form enables your specialist to see your tears more clearly. This helps them find out how long it takes for your eye to start drying out.
Once the drops are in your eye you will be asked to blink a few times and then keep your eyes open without blinking. Your specialist then uses a special light to see the dye and times how long it takes for the dry patch to appear.
If the patches begin to appear in less than ten seconds, this usually means you have dry eye syndrome.
If there is damage to the surface of the eye the fluorescein dye test may show up affected areas.
The dye is only temporary and will not change the colour of your eye.
The Schirmer's test
Small strips of blotting paper are hooked over your lower eyelid. After five minutes, the strips are removed and studied to determine how wet the paper is. If the paper has wetted less than 10mm in five minutes without anaesthetic eye drops, this indicates dry eye syndrome.
The Lissamine Green test
A non-toxic dye known as lissamine green is diluted with saline and dropped on the surface of your eye with a paper strip. The distinctive green colour of the dye allows the specialist to see early damage to the surface of the eye.
There is no cure for dry eye syndrome, but there are treatments to control your symptoms.
Once dry eye syndrome develops, some people have recurring episodes for the rest of their lives. The exact treatment for dry eye syndrome depends on whether symptoms are due to:
- not enough watery tears
- too much evaporation
- associated disease
The first thing to consider is whether there are any obvious factors that could be changed, such as minimising any medication that is causing symptoms. If there is an associated disease, this should be treated.
You may also be able to help prevent dry eye syndrome or ease your symptoms by adjusting your environment, keeping your eyes clean and improving your diet.
Read more information about.
Mild to moderate cases of dry eye syndrome can usually be treated using lubricant eye treatments that consist of a range of drops, gels and ointments. These lubricants aim to replace the missing water in the tear film, but do not contain the antibodies, vitamins and nutrients essential for eye health.
Some lubricants are available without a prescription over-the-counter (OTC) from a pharmacy.
There are many different types of eye drops and gels, so you can switch if your original choice does not work. However, some of the eye drops prescribed by your ophthalmologist if you have severe disease may have certain beneficial properties. It is important you discuss any changes you wish to make to your treatment with your doctor.
Some eye drops contain preservatives to prevent harmful bacteria from growing inside the medicine bottle. If your symptoms mean you need to use these eye drops more than six times a day, it's better to use preservative-free eye drops.
This is particularly important if your ophthalmologist has told you that you have severe dry eye disease. This is because preservatives in large quantities or after prolonged use (months or years) may damage the delicate cells on the surface of the eye or cause inflammation.
It is safe to use non-preserved eye drops at very high frequencies, including every hour or half-hour.
Most preservative-free preparations come as a package containing single dose units. These might be difficult to open if you have arthritis. Special eye drop delivery devices or tripods are sometimes provided by the suppliers to help the patient put their drops in. Certain non-preserved drops are also manufactured in multi-dose pumps. If you have difficulty putting in your drops, please discuss this with your doctor.
If you wear soft contact lenses, you may also need to use an ocular lubricant that is preservative-free, as preservatives attach to the contact lens and damage the eye. These types of eye drops may be more expensive.
'Oily tear' eye drops
Eye drops that replenish the oily tear and reduce evaporation from the surface of the eye are becoming more popular. These preparations include synthetic guar gums or liposomal sprays.
Liposomal sprays are over-the-counter medications and do not require a prescription. The liposomes are sprayed on the closed eyelid margins. When the eyes open, the liposomes spread across the surface of the eye, creating a new oily film. These are particularly useful if you haveor evaporative dry eye disease.
Eye ointment can also be used to help lubricate your eyes. However, it can often cause blurred vision, so it is probably best to use it last thing at night.
If you wear contact lenses, do not use eye ointments while wearing them. Ask your pharmacist or doctor for advice about which ointments may be suitable for you.
The underlying problem with long-term dry eye disease is inflammation. In such cases it is necessary to give anti-inflammatory treatments.
- steroid eye drops and ointments
- oral tetracyclines
- ciclosporin eye drops
Steroid eye drops and ointments
Steroids are potent anti-inflammatory drugs which can be given as eye drops or ointments in the severest cases of dry eye disease. They have side effects such asformation and raising intraocular pressure in about 30% of people. This group of treatments should only be used if you are being supervised by an ophthalmologist in an eye clinic.
Low doses of tetracyclines can be used as anti-inflammatory agents for a minimum of three to four months, sometimes much longer.
The most common drug used is doxycycline, but oxytetracycline and lymecycline are sometimes prescribed.
Ciclosporin eye drops
Ciclosporin is an immunosuppressing agent which has been used in the treatment of dry eye syndrome. These treatments are only available through a hospital eye department.
Autologous serum eye drops
None of the ocular lubricants currently available provide a substitution for the tear film, as they do not contain the vital nutrients required to keep the surface of the eye healthy.
When all treatment options are exhausted, autologous serum eye drops may be required.
This treatment is only available from the National Blood Service through an ophthalmologist and after approval of a funding application.
The patient is assessed for suitability for the blood donation. One unit of blood is taken under sterile conditions (as for regular blood donation). The blood cells are removed from the whole blood and the remaining serum put into eye dropper bottles. Due to quality standards, the process can take several months before the treatment is finally available to use.
Treating underlying medical conditions
If you have an underlying medical condition that is causing dry eye syndrome, your doctor will prescribe treatment for it or will refer you to an appropriate specialist.
If your underlying condition is a complex one, such as, , or rheumatic disease, and your symptoms are not settling, you will need to be referred to a specialist for treatment if you are not already receiving treatment for the condition.
To treat your dry eye syndrome, the specialist will address possible triggers, such as medicines or environmental factors, before trying to eliminate them. They will also advise on more complex treatments you might need.
If your dry eyes are severe and fail to respond to other forms of treatment, surgery may be an option.
Punctal occlusion involves using small plugs called punctal plugs to seal your tear ducts. This means your tears will not drain into the tear ducts and your eyes should remain moist.
Temporary plugs made of silicone are normally used first to determine whether the operation has a positive effect. If it does, more permanent plugs can replace the silicone ones.
In more severe cases, the punctal orifices are cauterised (sealed using heat). This permanently seals the drainage hole to increase the amount of tears on the surface.
Salivary gland autotransplantation
Salivary gland autotransplantation is usually only recommended after all other treatment options have been tried.
Salivary gland autotransplantation involves removing some of the glands that produce saliva from your lower lip and placing or grafting them into the side of your eyes. The saliva produced by the glands acts as a substitute for tears.
There are a number of things you can do to ease your symptoms or prevent dry eye syndrome.
Certain environments can irritate your eyes. Keep your eyes protected from:
- hot air
Wrap-around glasses may provide good protection. Avoid smoky environments and if you smoke you should try to stop.
Do not use eye make-up. Eyeliner and mascara will block the special glands in the eyelids and can cause a toxic inflammatory reaction.
Some cases of dry eye disease can be treated using specialised eyeware. These include specially made glasses called moisture chamber spectacles. These wrap around your eyes like goggles, helping to retain moisture and protecting your eyes from irritants.
If your previous contact lenses were causing dry eye disease, special contact lenses are also available. You should discuss various options with your high street optometrist.
Adjust your computer
Make sure that your computer workstation is positioned correctly to minimise eye strain. If you are using a computer at work, most employers have a health and safety officer or an occupational health representative who can advise you about this. Your monitor (screen) should stand at eye level or just below it.
If you use a computer, make sure that you take enough breaks away from your computer screen and blink your eyes regularly. Taking breaks every hour to "rest" your eyes may help reduce your symptoms.
Use a humidifier
A humidifier at work and home will moisten the surrounding air. Opening windows for a few minutes on cold days and longer in spring and summer will also help keep air moist and prevent build-up of mould.
Keep your eyes clean
Good hygiene will help improve dry eye syndrome, particularly if you have(inflammation of the eyelids).
There are three main steps to eyelid hygiene that should be performed once or twice a day:
- warm compresses
- gentle eyelid massage
- lid margin hygiene
- boil water and cool it to a warm temperature
- soak a clean flannel or eye pad in the warm water and gently place this over the eyes for around 10 minutes
- reheat the compress periodically by soaking it in warm water so that the flannel is not allowed to cool – the warmth melts the oils in the stagnated meibomian glands
- some people find a microwavable "eyebag" useful – make sure you clean the eyebag before and after use
- Gently massage your closed eyes by rolling your little finger in a circular motion – this will help to push the melted oil out of the glands. You cannot see the oil come out, as the droplets are tiny.
- Next, take a cotton-tipped applicator (cotton wool bud). With your eyes shut, gently roll the cotton bud downwards on the upper eyelid towards the lashes and eyelid margins, then repeat along the whole length of the upper eyelid. This will help express the residual oil out of all the glands.
- Repeat expression for the lower eyelid glands by rolling a clean cotton-tipped applicator upwards towards the lashes and the eyelid margin.
- If the oils have been stagnant in the glands for quite some time, they might have changed their chemical structure. It is possible that when the oil drains onto the surface of the eye after gentle expression, it might cause irritation, a bit like getting soap in your eyes. This is normal and should get better with time as the blepharitis comes under control.
Lid margin hygiene
- The expressed oils should be wiped away from the eyelid margin. This also helps to reduce bacteria, dust or grime that might have accumulated along the eyelids while blinking, and also any remaining crusts.
- There are many recipes for cleaning solutions. Boil a pint of water in a kettle and pour into a clean bowl. Add one teaspoon of bicarbonate of soda or a few drops of tea tree oil. Do not use baby shampoo, as this is fragranced and can make things worse.
- Soak clean cotton wool in the warm solution and remove crustiness from around the eyelids, paying special attention to the eye lashes. Throw the cotton wool away. If necessary, repeat with clean cotton wool.
- Dip a clean cotton-tipped applicator into the solution and gently clean the eyelid margins by wiping the cotton bud along the rims behind the roots of the lashes, the bases of the lashes and the lengths of the lashes.
- Alternatively, commercially available cleaning solutions or sterile lid wipes can be tried.
Sometimes your doctor might prescribe an antibiotic ointment to rub along the eyelid margins after the three-step lid hygiene regime. This is usually used only for a short period of time. If there is inflammation, anti-inflammatory eye drops or tablets may be required.
There is increasing evidence that suggests a diet high in omega-3 fats can help improve ocular surface health, meibomian gland function and dry eye disease.
This also has a wide range of health benefits, including reducing the risk of heart disease, joint problems and macular degeneration.
The most important omega-3s are:
- eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) – both found in wild fish
- alpha-linolenic acid (ALA) – found in green leafy vegetables, flaxseed, soya beans, canola oil and walnuts
However, it is important to maintain a balance with omega-6 fatty acids, found primarily in vegetable oils, red meat-derived saturated fats, fast foods, evening primrose oil and borage oil.
The best way to redress the omega-3 versus omega-6 balance is to increase oily fish intake, such as:
- fresh tuna (not canned, as the canning process removes the beneficial oils)
Aim to eat at least two portions of fish a week, one of which should be oily fish. Omega-3 supplements are also effective.
Although most people only experience mild symptoms, severe cases of dry eye syndrome may cause complications.
Conjunctivitisis inflammation of the conjunctiva (the transparent layer of cells that covers the white part of the eyeball and the inner surfaces of the eyelids).
Most cases of conjunctivitis caused by dry eye syndrome are mild and do not need specific treatment. However, if you have conjunctivitis that becomes severe and chronic (long-term), seek treatment advice from a specialist.
Ulceration of the cornea
In severe cases of untreated dry eye syndrome or cases that do not respond well to treatment, the associated inflammation (redness and swelling) can damage the surface of the cornea (the transparent layer at the front of the eye). This is called keratitis.
Sometimes the cornea can become vulnerable to ulceration and infection, which is a sight-threatening condition. This is frequently associated with pain. It is essential you go to an accident and emergency department if you notice reduction in your vision.