WHAT IS DRY EYE?
Dry eye is a chronic condition where there are not enough tears to sufficiently lubricate and nourish the eye. The glands involved in tear production either fail to produce enough tears or produce tears of poor quality.
Tears play an important role in maintaining the health of the front ocular surface. Tears lubricate and moisten the cornea, and provide an interface for oxygen exchange. They remove and flush away bacteria and allergens, preventing the eye from infection. Tears are also necessary for clear vision, by creating an even and smooth optical surface.
WHAT MAKES UP TEARS?
The tear film is composed of 3 layers:
- Outer lipid layer: reduces surface evaporation of tears and acts as a smooth lubricating layer.
- Aqueous layer: nourishes and protects the cornea.
- Inner mucin layer: helps the tears adhere to the eye.