Lysozyme content of tears in normal subjects and in patients with external eye infections.

We studied the lysozyme content of tears in 267 subjects (521 eyes), including 241 healthy subjects, 7 patients (14 eyes) with bilateral blepharitis, 8 patients (12 eyes) with conjunctivitis, and 11 patients (16 eyes) with keratitis. The concentration of lysozyme in the tears rises with age between childhood and maturity. The highest values were seen in the age group of 21-40 years, and a decrease of lysozyme concentration occurred with an increase in age from 30-40 years. The mean lysozyme content of tears was 1,768 micrograms/ml in healthy subjects; no significant differences occurred between the sexes. Patients with blepharitis, conjunctivitis, and keratitis had normal mean lysozyme content of tears. The tears of patients with herpes simplex keratitis had low lysozyme values.