Keeping Your Eyes Healthy with Tears

On days with heavy fine dust, exposure to air conditioning in summer, or dry air from heating in winter, your eyes may sting or feel dry, causing tears to flow. This is a natural defense mechanism where the cornea reacts sensitively to external irritants by producing tears for protection. It's also a common symptom of dry eye syndrome.

▲ Trends in the Number of Dry Eye Syndrome Patients Over the Past 5 Years, Source: Health Insurance Review and Assessment Service

According to statistics from the Health Insurance Review and Assessment Service, the number of patients treated for dry eye syndrome was 2.499 million in 2016, 2.616 million in 2017, 2.579 million in 2018, 2.679 million in 2019, and 2.438 million in 2020, averaging approximately 2.56 million annually. The primary causes are attributed to increased smartphone usage and the worsening of environmental factors such as fine dust.

▲ Introduction to Antibacterial Components in Tears, Source: Experimental Eye Research (2013 Study)

One key factor in maintaining eye health is tears. Beyond simply keeping the eyes moist, tears serve as a protective barrier. Understanding the protective functions of tears is essential for eye health. When dust or foreign substances enter the eyes, tears are naturally secreted to flush out these irritants and keep the eyes clean. In this process, tears act as a shield against external stimuli, serving as one of the eye's fundamental self-defense mechanisms.

1. Problems Caused by Insufficient Tears

When tears are lacking, the eyes can become dry, leading to blurred vision or fatigue. This occurs because the eye's surface does not receive adequate moisture. Tears are not just a simple liquid; they are critical in maintaining eye health. They deliver oxygen and nutrients to the cornea, making proper tear production essential for preserving vision and the overall condition of the eyes.

2. Structure and Function of the Tear Film

                                  ▲ Structure of the Tear Film

Tears consist of three primary layers: the mucus layer, the aqueous layer, and the lipid layer. Each layer plays a critical role in maintaining eye health and supporting its normal functions.

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1) Mucus Layer

The innermost layer, the mucus layer, enhances the adhesive properties of tears, allowing them to adhere effectively to the cornea.

• It helps remove foreign substances.
• Reduces friction between the eyelid and the cornea, enabling smooth eye movement.

This layer reduces dryness and ensures a comfortable, clear vision.

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2) Aqueous Layer

The middle layer, the aqueous layer, makes up the majority of the tear film and is essential for:

• Delivering oxygen and nutrients to the eye.
• Protecting the eye from external harmful agents, such as bacteria and dust, through its immune functions.

If this layer is insufficient, the eyes can easily become fatigued and more vulnerable to external infections.

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3) Lipid Layer

The outermost lipid layer acts as a protective barrier to prevent tear evaporation and keep the eyes from becoming dry.

• It helps maintain the balance of the tear film and ensures even distribution over the eye surface.

When the lipid layer is compromised, the risk of developing dry eye syndrome significantly increases.

3. Causes of Dry Eye Syndrome: Meibomian Gland Dysfunction

Dry eye syndrome is commonly thought to be caused by factors such as aging or chronic autoimmune diseases like Sjögren's syndrome. However, many modern individuals, even those who are not elderly, are exposed to environments that contribute to dry eyes.

As a result, complaints of dry eye syndrome are increasingly common among younger people. This condition is no longer limited to a specific age group but has become a widespread eye issue that can affect individuals of all ages.

▲ Checking Meibomian Gland Loss Using Meibography ⓐ No gland loss ⓑ Less than 33% gland loss ⓒ 33% to 66% gland loss ⓓ More than 66% gland loss

One of the main causes of dry eye syndrome is Meibomian Gland Dysfunction (MGD). Inside our eyelids, there are small glands called Meibomian glands, which secrete oils that form the lipid layer of the tear film, helping to protect the eyes.

However, when the function of these glands is disrupted, Meibomian Gland Dysfunction can occur. In this condition, the secreted oil can block the gland openings, causing inflammation. This prevents the proper formation of the tear film, which ultimately fails to protect the surface of the eye, leading to dryness and potentially causing dry eye syndrome.

In fact, approximately 80% of adults experience dry eye syndrome at least once in their lives. If left untreated, the tear film that protects the cornea will not function properly, which can lead to corneal damage, infection, and vision impairment. In severe cases, it can even lead to blindness. Therefore, if symptoms persist, it is essential to see a specialist immediately for treatment.

Tears have a significant impact on our eye health and vision. Particularly, when tears are insufficient or imbalanced, vision can become blurry, and the eyes may feel uncomfortable. Dry eye syndrome is a common issue for many people, but with proper management, clear vision can be restored more easily than expected. Since vision impairment can start from simple tear-related issues, it is crucial to pay attention to eye health regularly.

Fortunately, dry eye syndrome can be effectively managed with relatively simple treatments or procedures. By regularly checking the tear condition through eye exams and receiving necessary treatments, you can experience not only improved vision but also enhanced comfort for your eyes. With consistent care, you can maintain clear and bright vision.