The tear film on the front surface of your eye is made up of three layers. Problems with each tear layer can play a role in dry eye.
- A watery layer, which is produced by the main tear gland, the lacrimal gland. The watery layer transports important things such as oxygen and electrolytes to the cornea(front of the eye). Insufficient production of the watery layer can result in dry eye.
- An oil layer, produced by oil glands in the eye lids. The openings of the oil glands are at the base of each eye lash along the lid margin. The oil layer coats the tears to reduce evaporation. Without a healthy oil layer the tears evaporate off the eye surface too quickly causing dry eye.
- A mucus layer provides natural lubrication for the tears against the eyes surface. If you aren't producing enough of the watery layer, or if the oil layer gets too thin, then the mucus layer dries up and your eyes feel dry and irritated.
Causes of dry eye
Causes of dry eye can be very complex. Some of the common underlying causes can include:
- Sjögren’s Syndrome
- Omega-3 deficiency
- Long term contact lens wear
- Throid eye disease
- LASIK or Laser eye surgery
Dry eye treatments usually involve improving the production of the oil layer, to help stabilise the tear film. Or drops to rehydrate the eye and replenish the natural tear film.