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If your eyes burn, itch, feel "gritty" or become blurry towards the end of the day, you may have dry eye. This guide explains what actually happens on the surface of the eye, why it happens to you in particular, how the problem is diagnosed, and what you can do when drops from the pharmacy are no longer enough.
What is dry eye?
Dry eye (dry eye disease) is a disease of the eye surface in which the tear film loses its balance. The definition accepted today, from the international TFOS DEWS II workshop in 2017, describes it as a multifactorial disease in which loss of balance (homeostasis) of the tear film is accompanied by symptoms. The process involves tear instability, too high a concentration of salts in the tears (hyperosmolarity), inflammation and damage to the eye surface, and sometimes also changes in the sensory nerves of the cornea.
In simple terms: the tears cannot keep the eye surface moist, smooth and protected between one blink and the next. The result is discomfort, unstable vision and eyes that tire quickly.
The tear film and the vicious circle
The tear film is very thin, but cleverly built. Its base is a watery gel rich in proteins and mucus (mucin), which clings to the surface of the cornea and the conjunctiva. Spread over it is a very thin layer of oil, produced by the meibomian glands (tiny oil glands in the eyelid margins). The oily layer is the "lid" that stops the tears from evaporating.
When something goes wrong, what is known as a vicious circle forms: the tears evaporate quickly or there are not enough of them, they become too concentrated, the high concentration irritates the eye surface and triggers inflammation, and the inflammation further damages the cells that produce mucus and the glands. The tears then become even less stable, and the circle continues. That is why dry eye tends to be chronic, and why good treatment needs to break the circle, not just add fluid.
Two main types: increased evaporation and a lack of tears
The modern classification divides dry eye into two main mechanisms, which often occur together:
- Evaporative dry eye: the amount of tears is normal, but they evaporate too quickly. The most common cause is meibomian gland dysfunction (MGD), in which the oil the glands produce is thick or scanty. Incomplete blinking (for example at screens), inflammation of the eyelid margins (blepharitis) and rosacea also contribute to evaporation.
- Aqueous-deficient dry eye: the lacrimal gland produces too little fluid. This happens with age, in autoimmune diseases such as Sjögren's syndrome, after a bone marrow transplant, and as an effect of certain medicines.
Most patients have an evaporative component, and MGD is the most common cause of dry eye. This is one of the reasons why drops alone are not always enough: they add fluid, but they do not repair the oily layer.
Who gets it?
Dry eye is very common. According to the TFOS DEWS II Epidemiology Report, prevalence worldwide varies over a wide range, roughly between 5% and 50% of the population, depending on the definition used and the population studied. The risk is higher in:
- Older people, and women more than men, partly because of hormonal changes.
- People who work long hours at screens, where the blink rate drops and blinks become partial.
- Contact lens wearers.
- People who have had eye surgery, including laser vision correction or cataract surgery.
- People with autoimmune diseases, diabetes, rosacea or thyroid eye disease.
- People taking medicines such as antihistamines, some medicines for depression and anxiety, or acne medicines from the isotretinoin group.
- People who live or work in a dry, air-conditioned or dusty environment.
The symptoms
Symptoms vary from person to person, and they do not always match what the doctor sees in the examination. The common ones are:
- Burning, irritation or a feeling of a foreign body or "sand" in the eye (see also burning eyes).
- Redness, eye fatigue and difficulty reading or working at a screen for long periods.
- Blurred vision that improves after blinking.
- Sensitivity to light, wind and air conditioning.
- Excessive watering, which sounds paradoxical but is the eye's response to irritation.
- Difficulty wearing contact lenses.
- Pain, and sometimes pain that does not match what is seen in the examination (see painful eyes and neuropathic eye pain).
How is dry eye diagnosed?
Diagnosis starts with a conversation: when the symptoms appear, what makes them worse, which medicines and drops you use, and which general medical conditions you have. A validated symptom questionnaire, such as the OSDI, is usually used as well.
The eye is then examined under a special microscope (a slit lamp). The standard tests include:
- Tear break-up time (TBUT): a drop of yellow dye (fluorescein) shows how many seconds the tear film stays intact after a blink.
- Staining of the eye surface: the dye shows damaged areas on the cornea and the conjunctiva.
- Schirmer test: a small paper strip at the edge of the eyelid measures how many tears the eye produces.
- Meibomian gland assessment: gentle pressure on the eyelid shows whether the glands release oil, and what it looks like.
- Eyelid margin check: looking for signs of blepharitis and of the Demodex mite (a tiny parasite that lives in the eyelash follicles).
Putting the tests together helps show which mechanism is dominant in your case, and that is what determines the treatment. More detail is on the dry eye testing page.
The treatment ladder
The international guidelines suggest a stepwise approach: start with simple measures, and add treatments if the symptoms continue. In practice, treatment is matched to the type and severity of the dryness, and it does not always move step by step.
Step one: the basics at home
- Adjusting your environment: breaks from screens, conscious blinking, directing the air-conditioning flow away from your face, a humidifier in a dry room.
- Lubricating drops, preferably preservative-free drops when you use them often. There are many types, for example drops with hyaluronic acid.
- Warm compresses and eyelid hygiene, when there is a meibomian gland or blepharitis component.
- Checking with your doctor whether one of the medicines you take is contributing to the dryness. Do not stop a medicine without talking to your doctor first.
Step two: when the basics are not enough
- In-clinic treatments for the glands and eyelids: meibomian gland expression, IPL treatment (broad-spectrum pulsed light, not a laser) and eyelid margin cleaning with BlephEx.
- Punctal plugs, which keep your natural tears on the eye for longer.
- Drops and ointments that the eye doctor may prescribe, for example anti-inflammatory drops, or medical treatment for the eyelid margins. What they do and who they suit is explained on the prescription eye drops for dry eye page.
Step three: severe dryness
- Autologous serum eye drops, which are made from the patient's own blood.
- A bandage contact lens that protects the cornea like a "bandage".
- Other medical treatments, as decided by the doctor and with close follow-up.
For all the treatments available at the clinic, see the treatments page. If you already use drops regularly and the dryness does not go away, we have put together what is checked and what the next steps are on the page dry eye that is not improving with drops.
Drops bring relief, but they do not fix blocked meibomian glands or calm inflammation. If you use drops more than four or five times a day and still have symptoms, that is a good indication that it is worth finding out what the cause is.
When should you see a dry eye specialist?
Many people manage well with drops and good habits. It is worth having a thorough examination when:
- Symptoms continue for several weeks despite preservative-free drops, compresses and eyelid hygiene.
- The dryness affects your work, reading, driving or sleep.
- You have a general medical condition linked to dryness, such as Sjögren's, rosacea or a thyroid condition.
- You are about to have eye surgery, or the dryness started after surgery.
- You keep coming back with styes, eyelid inflammation, or contact lenses that you can no longer tolerate.
A dry eye specialist will check which mechanism is driving your dryness and build a plan that treats the cause, not just the symptom. You can read about what happens at the consultation and about the Dry Eye Clinic in Haifa.
When to see a doctor straight away: a sudden drop in vision, severe eye pain, redness with strong sensitivity to light, pain and redness in contact lens wearers, or any injury to the eye or exposure to a chemical. In these situations do not wait: see an eye doctor or go to an emergency department as soon as possible.
Want a basic explanation first?For a basic, simple guide to dry eye: the guide on the Mitzmutz site
Frequently asked questions
Is dry eye a real disease or just discomfort?
Dry eye is a recognised disease of the eye surface and the tear film. It can affect the quality of your vision and your quality of life, and in severe cases it can also damage the cornea, so it is worth taking seriously.
How can I have dryness if my eyes water?
When the eye surface is irritated, the lacrimal gland releases watery reflex tears. They wash the eye for a moment, but they do not last like a healthy tear film. That is why excessive watering is a common symptom of dry eye.
Does dry eye go away on its own?
Temporary dryness, for example after a flight or during a period of long hours at a screen, can pass. Chronic dry eye usually does not disappear on its own, but it can be well controlled with treatment that is matched to the cause.
When should I see a dry eye specialist?
When symptoms continue for several weeks despite preservative-free drops, compresses and eyelid hygiene, when you need drops many times a day, or when you have a general medical condition linked to dryness, such as Sjögren's syndrome.
Home care not enough? We can look into it.
At the dry eye clinic in Haifa we find out what is causing the dryness and build a personal treatment plan.
Sources
- Craig JP, Nichols KK, Akpek EK, et al. TFOS DEWS II Definition and Classification Report. Ocul Surf. 2017;15(3):276-283.
- Bron AJ, de Paiva CS, Chauhan SK, et al. TFOS DEWS II pathophysiology report. Ocul Surf. 2017;15(3):438-510.
- Stapleton F, Alves M, Bunya VY, et al. TFOS DEWS II Epidemiology Report. Ocul Surf. 2017;15(3):334-365.
- Wolffsohn JS, Arita R, Chalmers R, et al. TFOS DEWS II Diagnostic Methodology report. Ocul Surf. 2017;15(3):539-574.
- Jones L, Downie LE, Korb D, et al. TFOS DEWS II Management and Therapy Report. Ocul Surf. 2017;15(3):575-628.
- Nichols KK, Foulks GN, Bron AJ, et al. The International Workshop on Meibomian Gland Dysfunction: executive summary. Invest Ophthalmol Vis Sci. 2011;52(4):1922-1929.
The information on this site is general only. It is not medical advice and does not replace an examination by an eye doctor.