Dry eye syndrome

What is dry eye syndrome?

Tears are an important part of your eye health. They help to keep your eyes lubricated, protect them against infections, and clear away debris from the surface of your eyes. Dry eye syndrome (DES), or dry eye, can happen for a number of reasons, and is caused by a disruption in the quality or quantity of tears that the eyes produce.

Common causes

Dry eye is relatively common, with one study showing a prevalence of 21% in a Canadian cohort¹. 

Dry eye syndrome happens when your eyes stop making tears or don’t produce the ‘right’ tears needed to nourish and lubricate the eye. Tears are an important part of your eye health as they help to keep your eyes moisturized, protect them against infections, clear away any debris from the surface of your eyes and keep your vision clear.

A normal tear film is made up of three main layers:

• Mucin layer – which lines the surface of the eye (the cornea) and makes the tears stick to the eye 

• Aqueous (water) layer – this nourishes and protects the eye 

• Lipid (oily) layer – this sits on the outer surface of the tear film and prevents the tears from evaporating.

A breakdown in the production of any of these layers will lead to an imbalance in the tear film, which reduces the quality or quantity of tears. For example, if the lipid layer is reduced, the tears may evaporate too quickly as there is nothing to hold the aqueous layer in place. If there is a reduced aqueous layer, not enough tears are being produced.

Other common causes of dry eye include:

• Aging  

• Female gender; undergoing hormonal changes (such as menopause)  

• Use of certain medications  

• Low‑humidity environments  

• Contact lens wear  

• Decreased blinking (commonly associated with prolonged computer use)  

• Autoimmune diseases  

• Certain physical and functional eyelid conditions

Next steps

We want to help you see clearly and keep your eyes healthy for as long as possible. If your optometrist detects any signs of an eye condition during your comprehensive eye exam, they will determine an appropriate management plan that suits your needs.