Tear ferning and other lacrimal tests in normal persons of different ages.

We investigated in normal persons of different ages ranging from 4 months to 85 years the frequency of different ferning types as well as the results of the Schirmer I test, break-up time and tear protein profile. With increasing age, ferning types of higher degree were significantly more frequent. Furthermore, a correlation was found between the ferning test and low Schirmer test values (p less than 0.05) as well as break-up time (p less than 0.1). No correlation exists between ferning the test and tear protein pattern. These results indicate that tear ferning is independent from single tear proteins but in correlation with secreted watery volume and plays some role in tear film stability. Furthermore, these normal values of ferning and protein pattern can be used as references for different ages.