[Blepharitis component of dry eye syndrome]

This review contains a compilation of long-standing and more recent relevant information on chronic blepharitis, especially in the context of dry eye disease regarding epidemiology, symptoms, clinical findings and pathophysiology. Chronic blepharitis often represents the underlying cause of dry eye disease but remains undetected and untreated in many cases; however, it can be a result of (hypovolemic) dry eye disease and leads to sometimes severe corneal complications, which are illustrated by material from our own patient archives. Recent findings regarding the lipid composition in the tear film in correlation with that of Meibomian gland secretions and the hypothesis of a biofilm as the basis of chronic blepharitis as a theoretical, not yet proven addition to the previously known pathophysiological factors, are discussed.