Tear collection by absorbing polyurethane minisponges is highly advantageous in efficiency (recovery) and reproducibility (invariant electrophoretic polypeptide profiles). Tear donor comfort, simultaneous bilateral collection, and collections from several donors at once are additional major advantages of this collection method in studies involving single subjects and populations in health and disease.

The protein dye-binding assay we developed by using cellulose membranes or Schirmer strips is an efficient and convenient method for measuring tear protein concentration.