Hard-working tears

Have you ever wondered why we need tears? Aside from showing our emotions, these little wonders are needed daily to look after your eyes. We are going to examine why we need tears and what to be aware of to keep them flowing…

• Tears serve a protective function. They wash away debris that gathers on the surface of the eye, including bacteria and other micro-organisms, allergens, and irritating chemicals that can damage the cornea.
• Tears contain antibodies to help prevent infection.
• Tears carry nutrients to the cells on the surface of the cornea and remove corneal cells when they become damaged or die.
• Tears allow light to enter the eye undisturbed, which is necessary for clear vision. If debris collects on the corneal surface, or the surface is dry, it can affect how light enters the eye and result in blurry vision.

The front surface of the eye can be compared to the windshield of a car. Your eyelids are the windshield wipers, and the tears are like the windshield wiper fluid that washes away debris on the glass surface. Just as it would be difficult without windshield wipers or windshield wiper fluid for a driver to see through the windshield when dirt or debris collect on its surface, it is difficult to see if there are problems with the eyelids or tear production.

Tears are made up of oil, water, and mucous with some proteins mixed in for good measure. The conjunctiva (pinkish eyelid tissue that rests against the eyeball) produces mucins (glycosylated proteins) that help the tears flow across the surface of the eye. The largest component of the film is water, which is produced continuously by the lacrimal glands. Emotion, pain or harsh odours can trigger a reflex and create abundance of these watery tears. Hence, a strong onion or a hammer on the thumb will bring tears to your eyes. The final outermost component is a thin layer of oil that prevents the tears from drying up or evaporating too quickly as they move across the surface of the eye. The oily layer is produced by the meibomian glands, which are located in the eyelids.

Causes of dry eyes
The trick with tears is they need to have a proper balance of the three ingredients in order to bathe the surface of the eye and keep it comfortable and seeing clearly.

Medical conditions, medications, deficiencies in certain nutrients or vitamins, or injuries can inflame, block or impair the ability of your ocular system to produce each component properly or in the right amount. When evaluating a patient for dry eyes, the optometrist can assess whether there are abnormalities in any of the components of the tears. Dry eyes commonly result from abnormalities of the lipid or oil layer of the tear film so the eyelid is examined as well.

Not all dry eyes are dry!
Sometimes a symptom of dry eyes is too many tears that run uncontrolled, and irritate the delicate tissue around the eye. This is due to rapid evaporation of tears, which irritates the eye causing reflex tearing. Rapid evaporation of tears is often due to poor tear film quality.

How to maintain healthy tears
Proper eye health relies on the protection and maintenance of your eye surface so it is important to look after this tiny ingenious system. Recent studies have found that using a high quality Omega-3 dietary supplement is one of the best ways to manage dry eyes, providing relief along with other health benefits.

Your optometrist can help identify any issues affecting your tears and work with you to keep your tears flowing, eyes healthy and vision clear.

Photo ©iStockphoto.com/ Eric Hood

THE EYESITE: Ease computer eye strain
THE EYESITE: What the heck is a cataract?
THE EYESITE: Age-Related Macular Degeneration: How do you protect yourself?
THE EYESITE: A feast for the eyes… literally
THE EYESITE: Have you had your eyes checked lately?
THE EYESITE: Yoga and your eyes

THE EYESITE, is brought to you by ZoomerMedia Ltd. and IRIS, Canada’s largest eyecare provider and is dedicated to improving eyecare for all Canadians. From eye health and nutrition to vision technology, EYESITE is your source for reliable, informative and up–to-date information.