Dry eye is a disease of the ocular surface attributable to different disturbances of the natural function and protective mechanism of the external eye, leading to an unstable tear film during the open state. Despite the gain in knowledge of pathogenic factors of dry eye disease acquired in the past 20 years, there has been a lack of consensus on appropriate diagnostic criteria, classification of disease states, the aim of specific tests, the role of subjective symptoms and the interpretation of the results. A complete general and ocular examination has been performed, during the hospitalization in ophthalmological or internal disease departments, to all patients with lacrimal hiposecretion. The ocular examination consists in biomicroscopy, ophthalmoscopy, quantitative examination of lacrimal film (Schirmer I test, Jones test) and qualitative examination of lacrimal film (tear crystallization test, break-up time -BUT evaluation). Global test of quantitative estimation of lacrimal secretion, permits the measurement of total, basal, and reflex lacrimal glands secretion. The test has recorded low values in Sicca syndrome cases, revealing a correspondence between the results of the test and the appearance of corneal complications. We did not demonstrate an absolute relationship between the test results and clinical evolution; in some cases we considered that the poor general statement, and the association with severe general diseases, represented the most important factor in the evolution. Break-up time (BUT) is the most important and necessary test in determining the diagnostic of Sicca syndrome. The conjunctival impression reveals the modifications in epithelial cells and conjunctival goblet cells reveal cellular sufferance. The tear crystallization test also permits an easy and quick identification of the lacrimal film alterations existent in the Sicca syndrome. Break-up time is the most important test to diagnose Sicca syndrome and translates the mucinic layer integrity from the lacrimal film structure. It is correlated with the other quantitative or qualitative methods of lacrimal secretion.