Lysozyme concentration in tears of patients with sicca syndrome.

Fifty-three patients with sicca syndrome and 34 healthy controls had their tear lysozyme concentration examined. Lysozyme level was significantly decreased (P less than .0005) in all patients with low Schirmer test values as compared with healthy controls. Even in rheumatoid arthritis patients with normal Schirmer test results a low concentration of tear lysozyme was found. Tear lysozyme can be used to detect subclinical involvement of lacrimal glands in collagen diseases.