Functions of Tears
After blinking, a thin layer of tear fluid coats the surface of the eye and is retained there for some time. We refer to this as tear stability. Tears play a crucial part in preserving the eye's good functioning in addition to keeping the eye moist.
Preventing dryness
Tears shield the eye from irritation from the outside by coating the surface of the eye.
Supplying oxygen and nutrients to the eyes
Tears carry oxygen and nutrients to the surface cells of the eye because there are no blood veins there.
Preventing infection
Tears remove foreign objects that enter the eye. Moreover, tears include a compound called lysozyme that has an antibacterial effect and acts to stop microbial invasion and infection.
Healing damage to the surface of the eye
Tears have elements that can repair damage to the eye's surface.
Creating a smooth surface on the eye
Tears lubricate and smooth the surfaces of our eyes, allowing for proper light refraction and good vision.
Two-layer Structure of Tears
For the tears that protect our eyes to work properly, tear structure must be maintained. A lipid layer and an aqueous layer separate tears' outermost surfaces into two different layers.
Lipid Layer
The Meibomian glands on the corners of our eyelids secrete the lipid layer. By covering the outside, it stops tears from evaporating. Aging or inflammation-related decreases in Meibomian gland function can result in decreased oily material output, composition changes that give the oily substance a waxy appearance, and obstruction of the gland openings. If this takes place, tear stability falls and dry eye syndrome results. Meibomian gland dysfunction is the name for this type of anomaly, which is frequently observed in elderly persons.
Aqueous Layer
The majority of tears (95%) are made up of this layer, which also contains a variety of other materials, including proteins. It carries out the essential jobs tears do, like feeding the cornea with nutrition, shielding it from infection, and mending wounds. The lacrimal gland on the inside of the upper eyelid produces it. Moreover, mucus mucin, or secretory mucin, which is generated by the goblet cells on the surface of the eye, aids in evenly distributing tears. This mucin is crucial for the stability of tears, according to recent studies.
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