A medical symptom consisting of total or partial lack of tear secretion is called alacrimia or alácrima. There are two types of secretion of tears in humans: the basal, which maintains a thin permanent film on the cornea, preventing it from drying and opacifying, and reflects it, which can be chemical or emotional. Strictly it is considered to be a complete and congenital absence of tears (due to agenesis of the lachrymal glands or lack of nervous innervation). Secondary alacrimia can be a consequence of several diseases, one of which is Sjögren's syndrome. Bibliography
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