Secretory system Pathology of the tear film: deficiency of the aqueous layer -keratoconjunctivitis sicca. deficiency of mucous or meibomian secretions instability of the tear film(compensatory excessive aqueous secretion -paradoxical watering).Secretory system • Pathology of the tear film: • deficiency of the aqueous layer - keratoconjunctivitis sicca. • deficiency of mucous or meibomian secretions - instability of the tear film (compensatory excessive aqueous secretion - paradoxical watering)