How Do Tears Work?
One of the most important components of the eye that our optometrist may assess is your tear film. This layer of fluid that is excreted in response to debris, emotions, or cutting onions has a variety of important functions such as keeping the eye lubricated and protecting it from harmful objects or bacteria.
A healthy tear film can prevent conditions such as dry eye disease, fluctuating blurry vision or permanent damage and scarring to the cornea, the front surface of the eye. Understanding the tears is more complicated than it may seem but a quick summary is provided below.
What Is in Tears?
Your tears have three major components: aqueous (water), mucous, and oils. Historically, the tears were considered to be divided into three distinct layers of the components mentioned but recent research has shown that the mucous and aqueous components are dispersed throughout the tears in a gradient.
The mucous or mucins help attach the tears to the eye and is thus most concentrated close to the front surface of the eye. The aqueous component keeps the eye moist, holds antibodies that help protect against bacteria, and stores electrolytes like salts. The oil component protects the tears from evaporating too quickly.
Where Are Tears Made?
The various components of the tears are made in different parts of the eye. The aqueous component is produced mainly by the lacrimal gland, a small gland located in the upper and outer corner of each eye.
Other smaller glands that produce aqueous are dispersed throughout the eyelid as well. The mucous component is produced by goblet cells that are located throughout the conjunctiva, the transparent layer that lines the front of the eye as well as the inner surface of the eyelid. The oil component is produced by the Meibomian glands that are long stringy glands located in the upper and lower eyelids.
Where Do Tears Drain?
Tears exit the eye through small openings in the inner corner of the eye. These are known as punctae and are located in the upper and lower eyelid of each eye. These openings connect to a passageway that ultimately drains out the nose and back of the throat.
How Do I Maintain a Healthy Tear Film?
It is often best to start with an assessment from our optometrist in order to identify which components of the tears need attention.
Often, the oil component is lacking in patients and thus tears evaporate faster than the norm. This could be due to the Meibomian glands not functioning properly, incomplete lid closure or infrequent blinking. This prevents the tears from being spread evenly across the eye surface.
In this case, our optometrist will often recommend omega-3 oil supplements, hot compresses, blinking exercises or an ointment to be used before bed to prevent the eye from drying out.
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