Dry Eye Syndrome

Dry eye syndrome occurs when you do not produce enough tears (problem with tear quantity) or when the composition of tears is abnormal and cannot adequately cover the surface of the eye (problem with tear quality).

The tear film is an essential part for ensuring the overall health of the ocular surface. It cleanses, lubricates and nourishes the surface of the eye as well as protects the eye against infection. Both the quality and quantity of the tears must be maintained within certain levels to ensure a healthy ocular surface essential for good vision.

Chronic dry eye can lead to damage of the eye's surface and an increased risk of eye infections. Left untreated, severe forms of dry eye may even affect your vision.

You may have dry eye syndrome if you are having:

• Redness, irritation, or light sensitivity of the eye
• Heaviness or tiredness of the eyelid
• Foreign body or sandy sensation in the eyes
• Watery eyes which may be due to reflex tearing. The tear properties may be altered in dry eye so that there is insufficient protection of the ocular surface, resulting in irritation and reflex tearing
• Transient blurring of vision
  
  

What causes dry eye syndrome?

Dry eyes are caused by a lack of adequate tears or abnormal composition of tears. Your tears are a complex mixture of three basic layers oil, water, and mucus. This mixture helps make the surface of your eyes smooth and clear, and helps protect your eyes from infection. Problems with any of these layers can cause dry eye syndrome.

The outer layer (oil layer) is produced by the meibomian glands that line the edge of the upper and lower eyelids. The water layer is produced by the lacrimal gland located under the orbital rim bone just below the eyebrow. The mucus layer is produced by microscopic goblet cells in the conjunctiva.

Illustration: The eye and tear production

For some people, the cause of dry eyes may be due to an imbalance in the composition of their tears, or they do not produce enough tears to keep their eyes comfortably lubricated. Age, eyelid problems, certain ocular and systemic diseases and medications, and other causes such as environmental factors and hormonal changes can also lead to dry eyes.

Dry eye syndrome is diagnosed by tests and procedures done in the eye clinic that assess tear stability and amount of tear production. Some patients are not aware that they have symptoms of dry eyes until they consult an ophthalmologist.

Common treatments of dry eye syndrome include lifestyle changes and the use of eye drops.

Lifestyle changes such as reduced contact lens wear, lowering the height of computer monitors, less exposure to air conditioning, and a balanced diet with sufficient Omega 3 lipid components can have a significant impact on the control of dry eyes.

In cases of dry eyes that do not have clinical damage to the ocular surface, it is considered safe for patients to attempt to control the condition using over-the-counter medications called lubricants. Your ophthalmologist will advise you whether you have any ocular and systemic diseases associated with dry eyes. He/she will also advise you on drugs that can aggravate dry eyes and what to do in those circumstances.

Severe dry eye can be treated using more sophisticated methods such as steroid eyedrops, punctual plugs or surgery to close the lids.