What Is Dry Eye Syndrome (DES)?
Dry eye syndrome (DES) is a common eye problem, affecting a significant percentage of the population. Dry eye syndrome is seen in people of any race, age or sex, although it's more common in older patients and more common in women than in men.
What Are the Types of Dry Eye Syndrome?
Types of dry eye syndrome are related to the underlying problem that leads to dry eyes:
- Insufficient production of tears (also called keratoconjunctivitis sicca)
- Poor retention of tears
- Excessive evaporation of tears
What Are Causes of Dry Eye Syndrome?
Dry eye syndrome results from problems stemming from any of three layers of the tear film (a normal, thin layer of tears that covers the eye):
- The innermost layer is the mucin (or mucus) layer. It is produced by the conjunctiva (the clear membrane that lines the eye). The mucus helps the overlying watery layer to spread evenly over the eye.
- The middle layer is the watery (or aqueous) layer. It is essentially a very dilute salty solution. The lacrimal glands located under the upper lids produce this watery layer. This layer's function is to keep the eye moist and comfortable, as well as to help flush out any dust, debris, or foreign objects that may get into the eye. It's this tear layer that flows when we're crying or when the eyes are irritated.
- The outermost layer is the oily layer. These oils are produced by the meibomian glands, which are located on the eyelids. This important layer helps block evaporation of the watery layer between blinks.
The innermost mucin layer can be abnormal if there has been injury to the conjunctiva, for example after a chemical burn, Stevens-Johnson syndrome, cicatricial pemphigoid, malnutrition, or other inflammatory or autoimmune disorders.
The middle watery layer can be insufficient if the lacrimal glands are not functioning properly. This is seen in a variety of settings, including Sjögren's syndrome, rheumatoid arthritis, or lupus and other autoimmune disorders. Some medications, including antihistamines, antidepressants, and beta-blockers, may also decrease tear production.
The outermost oily layer may be poor if the eyelids' meibomian glands are plugged or clogged. This is often seen in meibomian gland dysfunction, blepharitis, and acne rosacea.
The eyelids can also play a role in causing dry eye syndrome if blinking is decreased or if the eyelids cannot close all the way.
- When you read, watch TV, or perform a task that requires close attention with your eyes, you may not blink as frequently. This decreased blinking allows excessive evaporation of the tears.
- Certain health conditions, such as stroke, Bell's palsy, or thyroid eye disease, can make it difficult to close your eyes on your own.
- Abnormal eyelid position following surgery, trauma, or certain skin conditions can also interfere with producing and maintaining a healthy tear film.
- Eyes can also be dry when exposed to wind from fans and vents.
What Are Dry Eye Syndrome Risk Factors?
The main risk factors include the following:
- Increasing age
- Meibomian gland dysfunction (plugged oil glands of the eyelids) and acne rosacea
- Autoimmune disorders
- Scarring from prior trauma, infection (keratoconjunctivitis), or exposure of the eye to toxic chemicals
- Eyelid malposition or paralysis preventing complete blinks
- Vitamin A deficiency
- Exposure to excess wind from fans, vents, heaters, and air conditioners
What Are Signs and Symptoms of Dry Eye Syndrome?
People with dry eyes typically experience the following symptoms and signs:
- Dry, gritty/scratchy, or filmy feeling in the eyes
- Burning or itching in the eyes
- Blurred vision
- Vision that varies with time of day
- A sensation of having a foreign body like sand in the eyes
- Light sensitivity and pain
- Excess tearing (paradoxically) when the eyes become extremely dry or when exposed to wind
- Intolerance to wearing contact lenses
- Redness of the eyes
- Discharge or crusty material on the eyelashes (when meibomian gland dysfunction is present)
Symptoms and signs often worsen in dry climates, in windy conditions, in higher temperatures with lower humidity, with prolonged use of your eyes (for example, reading, watching TV), and toward the end of the day.
Often there may be intermittent excessive tearing with dry eyes. Irritation may cause reflex tearing, in which a large amount of tears are produced all at once. The excess tears pour over your eyelids and down your cheeks. A short time later, your eyes may become irritated again, and the whole process may repeat itself.
When Should Someone Seek Medical Care for Dry Eye Syndrome?
If you routinely experience any of the following symptoms, you should probably see your eye doctor (optometrist or ophthalmologist):
- eye pain,
- excessive tearing,
- dry, gritty/scratchy, or filmy feeling in the eyes,
- burning or itching of the eyes,
- redness of the eyes,
- blurred vision,
- difficulty adjusting to contact lenses,
- a sensation of having a foreign body in the eyes, or
- light sensitivity.
What Questions Should People Ask Their Doctor About Dry Eye Syndrome?
- Is there a specific cause for my dry eyes?
- What is the most effective treatment for my dry eyes?
- Is there anything I can do to decrease the need for eyedrops or artificial tears?
What Exams and Tests Diagnose Dry Eye Syndrome?
Your eye doctor will take a thorough history of your eye and medical health, noting any conditions that might cause or worsen dry eyes.
During your eye examination, your eye doctor may perform the following tests.
- The front of your eyes are examined using a special microscope called a slit lamp microscope.
- The amount and thickness of the tear film is inspected.
- The stability of the tear film is assessed by checking the tear break-up time (the time it takes for the tear layer to evaporate between blinks).
- The conjunctiva and cornea are examined for signs of dryness using special dyes. The eyelids are checked for signs of meibomian gland dysfunction and for proper, complete blinking.
- A complete eye exam may also reveal signs of an underlying medical condition that exacerbates the dry eye.
- Different dyes may be used during your eye examination.
- Fluorescein is a yellow dye that stains the dry cornea where the epithelial cells (ocular surface) have been worn away due to the lack of an adequate protective tear film.
- Rose bengal is a red dye that stains the cornea and the conjunctiva where the cells are unhealthy due to chronic dryness. Lissamine green is a green dye that likewise can help differentiate between normal and abnormal ocular surface cells of the cornea and conjunctiva.
- Schirmer tests measure the amount of tears produced by your eyes. In this test, your eye doctor places the end of a thin strip of filter paper just inside the lower eyelid. After a minute, the filter paper is removed, and the amount of wetting is measured. Less wetting of the filter paper is more indicative of DES.
- The osmolarity (salt content) of the tears may be measured. If autoimmune diseases are suspected as a cause of DES, blood tests may be performed to look for markers of various autoimmune conditions.
- Rarely, a biopsy may be taken (for example a biopsy of the conjunctiva to look for cicatricial pemphigoid).
Are There Home Remedies for Dry Eye Syndrome?
To help alleviate your symptoms from DES, you may want to try these self-help tips at home.
- A humidifier puts more moisture in the air. With more moisture in the air, your tears evaporate more slowly, keeping your eyes more comfortable. Both furnaces in the winter and air conditioning in the summer decrease the humidity in the air.
- Avoid exposure to excessive air movement by decreasing the speed of ceiling fans and/or oscillating fans. Outdoors, block wind with good wrap-around sunglasses.
- Large amounts of dust, smoke, pollution, or other particulate matter in the air may worsen the symptoms of dry eye. In those situations, an air filter may be helpful.
- People with meibomian gland dysfunction, rosacea, or blepharitis will be instructed to use warm compresses and do daily eyelid scrubs with baby shampoo to improve the quality of the oily layer. The heat warms the oil in the oil glands, making it flow more easily. The cleansing also reduces the odds that the oil glands will become obstructed by debris. Artificial tear drops, gels, and ointments (available over the counter) help provide more moisture and lubrication. They can be used as often as needed. Preservative-free solutions are recommended if you use artificial tears more than four times a day. There is no single brand of over-the-counter drop that is best for everyone. They come in different formulations and textures, varying from thin and watery to thick and oily. Each individual will determine which drop provides the most relief from symptoms. Some drops may have a longer effect than others.
- For patients who wear contact lenses, special lens rewetting drops may be recommended by your doctor.
- Lubricating eye ointments may temporarily blur your vision if used during the day. Therefore, they are typically used to lubricate the eyes overnight. If you notice your eyes are dry mainly while you are reading, taking frequent breaks to allow your eyes to rest is helpful. Closing your eyes for 10 seconds every 10 to 20 minutes will increase your comfort.
What Medications and Procedures Treat Dry Eyes?
When over-the-counter eye lubricants are insufficient, prescriptions medications may be necessary.
- Cyclosporine A 0.5% (Restasis) and lifitegrast 5% (Xiidra) drops decrease inflammation in certain patients, particularly those with autoimmune disorders. Corticosteroid drops (such as fluorometholone, loteprednol, or prednisolone) also decrease inflammation. Corticosteroid drops, while very effective in most cases, should only be used under your doctor's supervision and according to her or his instructions because they carry risks for serious side effects such as keratoconjunctivitis infection, glaucoma, and cataracts.
- In advanced cases of dry eye syndrome, specially compounded treatments such as autologous serum drops, topical vitamin A ointment, and certain hormonal compounds may also help.
- Antibiotics drops or ointment are used if you have blepharitis.
- Low dose oral antibiotics doxycycline and minocycline are often helpful in controlling meibomian gland dysfunction, particularly when associated with rosacea. Vitamin A supplements and correction of other nutritional deficiencies may be necessary. This is particularly the case in those with malabsorption following gastric/intestinal surgery.
- Punctal occlusion: Near the inner corner of each eyelid is a small opening called a punctum that is the opening into the nasolacrimal duct, which is the drainage system connecting the tears to the inside of your nose. A procedure known as punctal occlusion can help dry eye syndrome by decreasing the drainage of tears into this tear drainage system. Tiny punctal plugs can be placed at or just inside these openings to block the normal drainage of tears, just like a stopper that you put in the drain of a sink to keep the water from flowing down the drain. These plugs can be temporary, made of a dissolvable material, or permanent. They can be removed if they result in excess tearing.
- In severe cases of dry eye syndrome, the punctum can be permanently closed by cautery (heat) or laser.
- Lateral tarsorrhaphy is a procedure in which the lateral (outside) one-third of your eyelids are taped, glued, or sewn together to decrease the amount of the eye that is exposed. This is typically reserved for extreme cases. If stroke, scarring, or nerve damage keeps your eyelids from closing properly, the eyes may need to be taped closed at night. Special goggles can also be worn to serve as moisture chambers. In some cases, small gold weights may be implanted into your upper eyelid to help it close all the way.
- Following a severe chemical injury or burn to the ocular surface, special bandage contact lenses such as those made from amniotic membranes may speed healing.
What Is the Prognosis for Dry Eye Syndrome?
The prognosis for dry eye syndrome varies, depending on the underlying cause. Many conditions mentioned above are chronic but manageable. In advanced cases, the prognosis worsens if the dryness results in corneal ulcers, keratoconjunctivitis infections, or scarring. Intensive treatment and close follow-up is needed in those cases.
Dry Eye Syndrome Picture
Dry eye syndrome is a common disorder of the tear film, which is made up of three layers, consisting of mucus, a very dilute saltwater solution, and fats or oils.