What is lipid layer instability?

In nearly 60% of cases, dry eye is exclusively the consequence of an instability of the lipid layer2, a consequence of a lipid deficit in the tear film. This layer protects the tear film from environmental factors. Its function is to prevent premature evaporation of the tear film and to stabilize its aqueous phase.

In case of alteration of the lipid phase, the underlying aqueous layer evaporates prematurely, hence the appearance of dry eyes. An unstable aqueous phase can also cause lacrimation.

Symptoms typically associated with lipid phase instability
tearing
Burning sensation
Predominantly morning symptoms improving during the day