[Studies relating to tear film stability (author's transl)]

Basic tear secretion (Schirmer test) and tear stability (fluorescein break-up time (BUT) were determined in 121 healthy subjects and related to age and goblet cell count. None of the eyes thus investigated had any inflammatory or degenerative changes of the lids, conjunctiva or cornea. A low goblet cell count was found in subjects with a short BUT but a short BUT was not uniformly correlated with a certain goblet cell count. There was no clear relation between goblet cell count and BUT or basic tear secretion. Basic tear secretion and BUT decrease continuously after the age of 50 to about half the values obtained in younger individuals. The generally held view that values of below 10 mm (Schirmer test) and below 10 s (BUT) are pathologic cannot be maintained without caution.