Method for Collection of Tear Fluid for Evaluation Its Antioxidant Properties

A technique of collection of the tear fluid with Schirmer strips for evaluation of the activity of the main antioxidant defense enzymes (superoxide dismutase, catalase, and glutathione peroxidase) in the tear fluid was proposed. The degree of extraction of the studied enzymes from the Schirmer strip is >85%. Cytometry showed that conjunctival and corneal cells can be transferred to the Schirmer strips during tear collection, which leads to sample contamination with intracellular fractions of the antioxidant enzymes. The approach proposed by us allows avoiding this contamination during tear fluid sampling. This technique makes it possible to increase the accuracy of determining the activity of antioxidant protection enzymes in the tear fluid and can be used for diagnostics of ocular surface pathologies in clinical practice.