What Causes Dry Eye?
Dry eye occurs when the eye is unable to keep its surface adequately lubricated due to an imbalance in the tear film, which protects the eye and helps maintain comfort.
The causes of dry eye can generally be divided into two main categories:
1. Reduced Tear Production
Dry eye may occur when the lacrimal glands do not produce enough of the watery component of tears to keep the surface of the eye adequately lubricated. This condition is medically known as keratoconjunctivitis sicca.
The main causes of reduced tear production include:
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Aging:
Tear production naturally decreases with age. -
Hormonal changes:
Hormonal changes can affect tear production and the function of the lacrimal glands, particularly in women after menopause. -
Autoimmune diseases:
Such as Sjögren’s syndrome, systemic lupus erythematosus, rheumatoid arthritis, and scleroderma. -
Thyroid disorders and certain chronic diseases:
Some health conditions may affect the function of the lacrimal glands and increase the risk of dry eye. -
Certain medications:
These include antihistamines, decongestants, certain antidepressants, diuretics, some blood pressure medications, and medications used to treat acne. -
Eye surgery:
Laser vision correction procedures such as LASIK may cause temporary dry eye due to their effect on the corneal nerves.
2. Increased Tear Evaporation
The eyes may produce an adequate amount of tears, but these tears may evaporate too quickly because of problems with tear quality or with the oily layer that helps prevent tear loss.
The main causes of increased tear evaporation include:
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Meibomian gland dysfunction:
These glands are located along the edges of the eyelids and are responsible for producing the oily layer that reduces tear evaporation. When they become blocked or do not function properly, the eyes become more susceptible to dryness. -
Blepharitis:
Inflammation of the eyelid margins may block the oil glands and affect tear quality. -
Reduced blinking:
This may occur in people with Parkinson’s disease and during prolonged periods of concentration while using a computer or smartphone or while reading. -
Prolonged contact lens wear:
This may affect the stability of the tear film and cause dryness and discomfort. -
Environmental factors:
Such as dry air, wind, smoke, air conditioning, or exposure to high temperatures. -
Eye allergies:
These may cause inflammation of the ocular surface and worsen dry eye symptoms.
Other Factors That May Increase the Risk of Dry Eye
Certain factors may also increase the likelihood of developing dry eye, including:
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A family history of dry eye.
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Smoking or continuous exposure to smoke.
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Living in a dry environment or an area with low humidity.
Is Dry Eye Dangerous?
Dry eye is generally not considered a serious condition when it is managed properly. However, in some cases, it can become more concerning, especially if it is left untreated for a prolonged period.
Complications of Untreated Dry Eye
1. Eye Inflammation and Increased Risk of Infection
Tears help protect the surface of the eye from germs and bacteria. Therefore, reduced tear production may make the eye more susceptible to inflammation and recurrent infections.
2. Inflammation and Irritation of the Ocular Surface
Persistent dryness may lead to inflammation of the surface of the eye, causing increased burning, stinging, and a sensation of having a foreign body in the eye.
3. Corneal Abrasions and Ulcers
In severe cases, dry eye may cause erosion of the corneal surface or lead to abrasions and ulcers. If left untreated, these problems may result in scarring that can affect visual clarity.
How Is Dry Eye Diagnosed?
Dry eye diagnosis does not rely on a single test. Instead, the ophthalmologist uses a combination of examinations to assess tear quantity and quality and determine the underlying cause of the symptoms.
Comprehensive Eye Examination
The doctor begins by reviewing the patient’s medical history, symptoms, and how they affect the eyes. The eyes and eyelids are then examined using a slit lamp to look for signs of dryness or inflammation and to assess the condition of the ocular surface.
Measuring Tear Production
Several tests can be used to measure tear production. One of the most common is the Schirmer’s Test, in which a small strip of paper is placed beneath the lower eyelid for 5 minutes, after which the amount of tears absorbed by the strip is measured.
The Phenol Red Thread Test may also be used as a quick method for assessing tear volume.
Assessing Tear Quality and Evaporation
The Tear Break-Up Time (TBUT) test is performed by placing a special dye in the eye and measuring how long it takes for the tear film to begin breaking up or evaporating.
Additional Tests
The doctor may recommend other tests, such as a Tear Osmolarity Test, which measures the concentration of components in the tears, or analysis of a tear sample to detect signs of inflammation or other factors associated with dry eye.
Tests for Conditions Associated With Dry Eye
In some cases, additional laboratory tests may be needed, such as antibody tests, to look for autoimmune diseases that may be contributing to dry eye, including Sjögren’s syndrome.
Dry Eye Treatment Options
Dry eye treatment depends on the underlying cause of the condition and the severity of the symptoms. Treatment aims to improve the function of the tear-producing glands, increase lubrication of the ocular surface, reduce tear loss, and address inflammation or other problems that contribute to dryness.
Common treatment options for dry eye include:
1. Artificial Tears
Artificial tears are the first-line and most commonly used treatment for dry eye, particularly in mild to moderate cases. These drops help compensate for insufficient natural tears and keep the surface of the eye lubricated.
Artificial tears are available in several forms, including:
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Lubricating eye drops.
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Eye gels.
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Lubricating eye ointments, which are often used before bedtime because they provide longer-lasting lubrication but may cause temporary blurred vision.
Preservative-free eye drops are generally preferred when frequent use is required throughout the day, as they may help reduce eye irritation.
2. Medications to Reduce Eye Inflammation
If dry eye is associated with inflammation of the ocular surface or eyelids, the doctor may prescribe medications that help reduce inflammation and improve tear film function.
3. Medications to Stimulate Tear Production
In some cases of reduced tear production, the doctor may prescribe medications that help increase tear secretion. These medications work by stimulating the glands responsible for producing tears and may be available as tablets, eye drops, or gels, depending on the condition.
4. Punctal Plugs
Punctal plugs may be used to treat dry eye caused by rapid drainage of tears from the eye. These are small plugs placed into the tear drainage openings located near the inner corners of the eyelids. They help to:
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Reduce tear loss.
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Keep natural tears and artificial tears on the surface of the eye for a longer period.
These plugs may be temporary or removable. In some cases, the tear drainage ducts may be permanently closed using thermal cautery.
5. Treatment of Meibomian Gland Dysfunction
If dry eye is caused by blockage or dysfunction of the meibomian glands, treatment focuses on improving the function of these glands, which are responsible for producing the oily layer of the tear film.
Treatment may include:
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Warm compresses.
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Eyelid massage.
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Eyelid hygiene.
6. Specialized Therapeutic Contact Lenses
In some cases of severe dry eye, scleral lenses may be used. These specialized lenses help protect the ocular surface and maintain a layer of lubricating fluid over the cornea, which can reduce dryness and improve vision in some patients.
7. Supportive Home Measures
Dry eye symptoms may also be relieved through certain daily measures, such as:
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Taking regular breaks while using digital screens.
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Blinking more frequently.
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Using a humidifier.
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Avoiding dry air or directing air conditioning toward the eyes.
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Avoiding smoking and exposure to smoke.
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Drinking an adequate amount of water.
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Eating foods rich in omega-3 fatty acids.
Frequently Asked Questions
Which vitamin deficiency is associated with dry eye?
Deficiency of certain nutrients may be associated with eye problems. Vitamin A is one of the most important vitamins related to eye health and tear production. Deficiency of other nutrients, such as omega-3 fatty acids, may also affect the health of the ocular surface in some people.
What is the relationship between tears and dry eye?
Tears are not simply a fluid that lubricates the eyes. They consist of several layers that work together to maintain the health of the ocular surface, including:
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The oily layer: Produced by the meibomian glands in the eyelids, it helps reduce tear evaporation and keeps the tear film stable for longer.
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The aqueous layer: Makes up a large portion of the tears and provides moisture and essential components that help nourish and protect the ocular surface.
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The mucous layer: Helps spread tears evenly across the surface of the eye and keeps them in place to maintain lubrication.
When there is an imbalance in the amount of tears or in the components of these layers, the eye may not receive sufficient lubrication, leading to dry eye symptoms such as burning, irritation, and a foreign-body sensation.
Can dry eye be cured permanently?
Many people with dry eye would like to eliminate the condition permanently. However, there is currently no single treatment that completely cures dry eye in every case. Doctors consider many forms of dry eye to be chronic conditions whose symptoms can be controlled and whose effects on the eyes can be improved with appropriate treatment and adherence to medical advice.
Dry eye symptoms may resolve in some cases when the underlying cause is temporary, such as exposure to dry environmental conditions or the use of certain medications. Chronic or severe cases, however, may require ongoing follow-up and an appropriate treatment plan to reduce symptoms, maintain eye health, and help prevent potential complications such as inflammation of the ocular surface or corneal ulcers.
Can dry eye cause blindness?
No. In most cases, dry eye does not cause blindness.
However, very severe and untreated cases may affect the corneal surface and lead to vision problems. Therefore, treating dry eye and controlling its symptoms is important to help prevent complications.
Can children develop dry eye?
Dry eye is not limited to adults and can also affect children. Treatment depends on the underlying cause, and the doctor may recommend lubricating eye drops or other appropriate treatments depending on the child’s condition.
Can dry eye occur during sleep?
Yes. Some people may experience dry eye during sleep. This may occur when the eyelids do not close completely while sleeping, exposing the ocular surface to air and increasing tear evaporation.
Can vitamin B12 deficiency affect the eyes?
Yes. Vitamin B12 deficiency may affect the eyes in some cases and can cause blurred vision or reduced visual clarity due to its effect on the optic nerve. This is more likely to occur when the deficiency persists for a long period without treatment. Vision may improve after vitamin B12 deficiency is treated if the condition is detected early.
Can dry eye cause headaches?
Yes. Dry eye may be associated with headaches in some people, although dry eye is not the only possible cause of headaches.
Headaches associated with dry eye may be related to:
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Eye strain while trying to focus.
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Prolonged screen use.
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Sensitivity to light.
How can dry eye be prevented?
To help reduce the risk of dry eye:
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Remember to blink regularly while working in front of screens.
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Use appropriate lighting while reading.
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Avoid using eye drops randomly for prolonged periods.
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Have regular eye examinations.
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Maintain a balanced diet and adequate hydration.
Can dry eye be treated at home?
If dry eye is mild, certain measures may help relieve the symptoms, including:
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Resting the eyes during screen use:
Take regular breaks and follow the 20-20-20 rule: every 20 minutes, look at something approximately 20 feet away for 20 seconds. -
Avoiding direct airflow:
Avoid directing air conditioning or fans toward the eyes, and try to stay away from environments filled with smoke or dust. -
Warm compresses:
Applying a clean, warm compress to the eyelids for a few minutes may help improve eye comfort. -
Sunglasses:
Wearing sunglasses outdoors can help protect the eyes from wind and dust and may reduce factors that worsen dryness. -
Maintaining hydration:
Make sure to drink an adequate amount of fluids throughout the day. -
Maintaining a balanced diet:
Sources of omega-3 fatty acids, such as fatty fish, nuts, and seeds, can be included as part of the diet.
When should you see an ophthalmologist?
Home measures may help relieve symptoms, but they do not necessarily treat the underlying cause of dry eye. It is therefore advisable to consult an ophthalmologist if:
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Dryness persists or occurs frequently.
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Symptoms do not improve despite using lubricating eye drops and taking care of the eyes.
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Eye discharge or other unusual symptoms develop.
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You find yourself needing lubricating eye drops frequently to keep your eyes comfortable.
Most importantly, redness-relief eye drops should not be used to treat dry eye, as they may increase eye irritation.
In conclusion, dry eye may begin with a mild symptom, but recurring symptoms should not be ignored. The earlier the underlying cause is identified, the easier it may be to manage the condition in a way that is appropriate for your needs. If you experience persistent or recurring symptoms, visiting Royah Hakim can help you assess the condition of your eyes and receive appropriate care.