Quantitative tear ferning. Clinical investigations.

The tears of 225 subjects were examined for several disorders of the eye by means of a newly developed method, the quantitative tear ferning test. Of the 225 subjects, 89 were normal controls, 24 were examined before and after cataract extraction, and 112 had some disease of the external part of the eye. Using the quantitative tear ferning test, it was shown that compared to normals, the ferning area was significantly decreased in cases of keratoconjunctivitis sicca, in primary and in secondary Sjögren's syndrome. This was also the case in infectious conjunctivitis and after cataract extraction, possibly due to exudation from the conjunctival vessels. In simple conjunctivitis, however, the ferning area was normal. The ferning method has a sensitivity and a specificity of the same order as the commonly used tests for Sjögren's syndrome (Schirmer I, BUT, rose bengale, lactoferrin).