What is dry eye?

Dry eye is a complex disease of the tear glands and surface of the eye that causes ocular discomfort, blurred vision and tear film instability which can lead to ocular surface damage.

In recent years, cases of dry eye have significantly increased due to deteriorating living conditions (pollution, computer screens, air conditioning, etc.).

Nowadays, almost one in three adults is concerned !


1 - Evaporative Dry Eye : due to lipid tear deficiency (accounts for 80% of cases)

In this case, even if the lacrimal gland works normally, a poor or insufficient oil layer may lead to tears evaporating 4-16 times faster than normal.

The lipid layer may be disturbed for many reasons :

  • A Meibomian Gland Dysfunction (The glands may be blocked due to a thick meibum)
  • Wearing contact lenses
  • Diseases and allergies that affect your eyes
  • Not blinking frequently enough (computer use, television…)
  • Outdoor environment such as windy conditions and a low humidity.
  • Air conditioning (extended travel by airplanes or cars)

2 - Aqueous Dry Eye : due to decreased aqueous tear production

It occurs when the lacrimal gland does not produce enough of the water component to keep the eyes moist. The final conclusion is a dry ocular surface. It could result from some diseases, such as Sjogren’s syndrome, medications or Lacrimal Duct Obstruction.

Dry eye symptoms

Dry eye syndrome manifest as visible symptoms of discomfort.
  • Itchy eyes and aching sensations
  • Burning sensation and grittiness, as though there’s sand in your eyes
  • Photophobia (light sensitivity)
  • The feeling that the eyelids are glued together in the morning
  • Eye irritation especially due to the wind or near to cigarette smoke
  • Inability to tolerate wearing contact lenses


The tear film that covers the ocular surface is composed of 2 layers:

  • The lipid layer which prevents tears evaporation is produced by the Meibomian glands.

Unharmed lipid laye

Impaired lipid layer