Tears are not just for crying but for the maintenance of the eye

Sjögren’s syndrome Tears and dry eye disease

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Have you ever wondered why tears flow as soon as we start to cry or while cutting an onion?  Tears serve a crucial role beyond emotional expression, as they contribute to the maintenance and well-being of our eyes. While commonly associated with emotions, tears play a significant role in keeping the eyes moist and safeguarding them against bacteria, dust, dirt, and other irritants. 

Composition of tears:  Tears are not merely water droplets that form when we cry. Tears are a complex biological mixture containing electrolytes, metabolites, lipids, mucins, some small organic molecules, and proteins alongside water.  This intricate composition provides several benefits for our visuals overall health and maintenance. The proteins in tears help maintain the osmotic balance, metabolic transport, and defence from bacteria. 

Types of tears: Lacrimal glands above each eye produce tears and blinking helps in the spread of tears across the surface of the eye. Three types of tears are produced, as follows: 

• Basal tears:   They are constantly present, serving as a source of lubrication and nourishment for the eye while forming a protective barrier to the cornea. 

• Reflex tears: These tears are formed when harmful irritants like smoke, dust, or foreign bodies need to be washed off our eyes and contain antibodies. 
• Emotional tears:   It is formed in the cerebrum as an indication of emotional distress.  It contains more protein-based hormones that help reduce hormonal and chemical levels in the body and mind.  

Layers of tears 

Tears are not simply saline water but are more complex than we think.  Each tear is made up of three layers i.e., the oily layer on the outside, the watery layer in the middle, and the inner, mucus layer. These layers together are known as tear film. The tear films primary function is to keep our eyeballs surface clean, moist, and lubricated, protecting foreign bodies, and nutrition to the cornea. The fluid in tears holds significant value in assessing health and disease. It serves as a valuable source of biomarkers for objective analysis of ocular and systemic diseases.  

What happens when eyes could not produce tears? 

The lacrimal glands continuously produce tears, and ducts in the inner corners of our eyes drain off excess tears down into our noses. This is why we always get a runny nose while crying. But in certain conditions, the production of tears slows down, and this can lead to the development of dry eye disease (DED).  

International Dry Eye Workshop (DEW)II defined DED as a multifactorial disease of the ocular surface characterized by a loss of homeostasis of the tear film and accompanied by ocular symptoms, in which tear film instability and hyperosmolarity, ocular surface inflammation and damage, and neurosensory abnormalities play etiological roles. 

What are the causes? 

Individuals with DED may have adequate drainage, but they produce few or inferior-quality tears. Dry eye can occur if the tear gland does not produce adequate tears and occurs when the meibomian glands on the eye are not producing enough oils for the outer layer of the tear film. As a result, the watery layer of tear film evaporates quickly and in turn, the lacrimal glands try to make more watery tears to compensate. But these tears produced cannot coat the eyes properly as the oily layer would. Many factors can cause DED, and some are listed below: 

1. Age 
2. Problem in secretion glands. 
3. Hormonal changes in women after menopause or during pregnancy.
4. Side effects of medication.
5. Certain medical conditions like autoimmune diseases (Sjogrens syndrome, rheumatoid arthritis), blepharitis, thyroid problems, and diabetes.
6. Smoke, dry windy climates, air conditioning, and persistent screen time.
7. Using contact lenses.

What are the symptoms? 

The common symptoms include scratchy eyes, burning or stinging sensation, sensitivity to light, blurred vision, mucus formation, and watery eyes with excess tears flowing down. 

How is DED diagnosed?  

The diagnosis of DED is very often done based on the symptoms.  Ophthalmologists diagnose dry eye disease through medical history, eye exams, and tests like measuring tear productivity, special dyes, and evaluation of the tear film constituents. 

How to manage and treat DED?  

The management of dry eye diseases focuses on relieving symptoms, improving tear production, and protecting the ocular surface, as it may damage the tissue and scar the cornea if kept untreated. Here are some treatment options: 

1. Artificial tears or ointments. 
2. Punctal plugs to prevent tear drainage.
3. Eliminating dryness and dust.
4. Diet modification.
5. Evaluation of medications.
6. Increased blinking.
7. Treatment of associated medical problems.

Tears are not just a reflection of our emotions but also an essential part of maintaining healthy eyes. Their multifaceted composition and functions, including lubrication, protection against infections, nourishment, and healing, contribute significantly to the overall well-being of our eyes. DED is a persistent condition and understanding the causes, recognizing the symptoms, proper diagnosis, and treatment can help in managing the condition effectively.

 Tears are beneficial to the eye’s health, but they are also critical aspects of emotional and social communication. -Unknown 

Watch video about Eye and Rheumatology Series: Dry Eye Conditions: Click here

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