Definition

Dry eye is a condition resulting from various factors affecting the tears and surface of the eye, leading to discomfort, vision impairment, and instability of the tear film, potentially damaging the eye's surface. Inadequate eye lubrication from tears can cause significant discomfort and prevents the eyes from effectively removing dust or foreign objects.

Tears are composed of fat, water, mucus, and protein, which maintain a smooth eye surface and give protection against infections. Another term for dry eye disease is keratoconjunctivitis sicca. This condition is more prevalent in women and tends to increase with age.

Causes

Dry eyes are categorized into two types based on their causes:

1. Aqueous Deficiency Dry Eyes

This condition is caused by reduced tear production due to impaired tear gland function or decreased tear volume. Factors include aging, certain diseases, medications, damage to tear glands from radiation or laser eye surgery can increase the risk of dry eyes.

2. Evaporative Dry Eyes

Occurs when tears evaporate too quickly, despite normal tear production. Causes include environmental factors such as wind, smoke, or dry air, infrequent blinking (e.g., during prolonged reading or computer use), and eyelid malpositions. An imbalance in tear composition due to blocked oil glands, eyelid infections, or skin disorders around the eyes can also contribute to the occurrence of dry eyes.

Risk Factor

Higher risk of developing dry eye disease is associated with:

• Age over 50 years, as tear production decreases with age.
• Certain diseases such as diabetes, rheumatoid arthritis, lupus, scleroderma, Sjogren's syndrome, thyroid hormone disorders, and vitamin A deficiency.
• Certain medications including antihistamines, decongestants, antidepressants, hypertension drugs, acne medications, Parkinson's drugs, and hormone replacement therapy.
• Hormonal changes due to pregnancy, birth control pills, or menopause.
• Wearing contact lenses.

Symptoms

The primary symptoms are dry eyes, and gritty sensation in the eyes. Additional symptoms include:

• Burning or itchiness
• Foreign body sensation
• Excessive tearing as a response to irritation
• Painful eyes
• Red eyes
• Sensitivity to sunlight
• Quick eye fatigue
• Blurred vision, worsening in low humidity and high temperatures

The severity of symptoms can vary. While often mild, untreated symptoms can lead to more severe symptoms. Dry eyes can cause visual impairment, eye inflammation, increased risk of bacterial infection, or corneal scarring.

Diagnosis

To diagnose dry eyes, an ophthalmologist will review your medical history, conduct a physical examination, and perform diagnostic tests if needed. The doctor will inquire about your symptoms and medical history.

A thorough examination of patients’ medical history includes inquiring the onset of symptoms, specific complaints, risk factors they may have, such as occupation and environment factors at play, and the presence of other diseases such as Graves' disease, Sjogren's syndrome, diabetes, and vascular diseases. Commonly used questionnaire instruments include the Ocular Surface Disease Index (OSDI), McMonnies Questionnaire, Women's Health Study Questionnaire, or Dry Eye-Related QoL Score (DEQ).

The physical examination typically includes a Schirmer test to measure tear volume. This test involves placing a special absorbent paper on the lower eyelid for 5 minutes. A result of less than 10 millimeters of wet paper indicates dry eyes.

Another diagnostic test, crucial for diagnosing dry eye, involves using fluorescein dye to measure Tear Film Break Up Time (TBUT). This test evaluates the stability of the tear film. The dye is applied to the eye, and the interval between the last blink and the appearance of a dark spot on the cornea is measured. A TBUT of less than 10 seconds suggests dry eyes.

Management

The treatments of dry eyes vary based on the underlying cause. Generally, it aims to alleviate symptoms and address the root cause. If the cause is identifiable, such as a specific disease or medication, treatments will target the disease or involve stopping the medication suspected causing dry eyes.

For mild dry eyes, using eye lubricants or artificial tears is effective. Artificial tears, available as drops, gels, or ointments, can be purchased over the counter and function as tear substitutes to moisturize the eyes. They are typically administered four times daily, or up to 10-12 times in severe cases.

If artificial tears do not alleviate symptoms, several therapeutic options are available:

• Medications: Antibiotics or immune system suppressants to reduce corneal inflammation, can be prescribed by a doctor.
• Tear-stimulating medications: Cholinergic drugs, also prescribed by a doctor.
• Autologous serum eye drops: Made from the patient's blood, these are used for severe dry eye cases unresponsive to other treatments.

Several procedures can be performed based on indications:

• Tear duct blocking: Silicone plugs are used to reduce tear evaporation, either temporarily or permanently.
• Special contact lenses: Designed to protect and moisturize the eye surface.
• Oil gland unblocking: Conducted with thermal pulsation, involving gentle eyelid massage with heat.
• Intense-pulsed light therapy: Light therapy followed by eyelid massage to alleviate symptoms.

Complications

Untreated dry eyes can lead to:

• Increased risk of eye infection due to insufficient tear supply and ocular surface damage.
• Damage to the eye surface, including corneal inflammation and potential visual impairment.
• Decreased quality of life, disrupting daily activities like reading or driving.

Prevention

Preventive measures include:

• Protecting eyes from hot, smoky, dusty, or windy conditions. Use a humidifier or air filter indoors.
• Avoiding eye makeup.
• Quitting smoking.
• Regulating time spent in front of computer screens.
• Using warm compresses and cleaning eyelids to remove dirt or oil.
• Maintaining eye hygiene.
• Consuming omega-3 fatty acids found in fish like mackerel, tuna, sardines, or salmon.

When to see a doctor?

If you experience symptoms indicating dry eyes, consult an ophthalmologist. The doctor will examine to diagnose dry eyes or rule out other conditions. Though dry eye disease is often mild and can be managed independently, professional treatment can accelerate healing.

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