Decreased mucin concentrations in tear fluids of contact lens wearers

Characteristics of tear-film may be influenced by contact lens wear, because contact lenses present the habitual, direct rubbing action of the lids upon the covered ocular surface and may cause changes of tear-film. In the present paper, influence of contact lens on proteins in tear samples was studied using carbohydrates attached to the protein as a marker. We found that N-acetylneuraminic acid (Neu5Ac) was significantly decreased in tear samples of volunteers wearing contact lens (wearing, 86.1 ± 57.7 nmol/ml; normal, 190.2 ± 121.9 nmol/ml). Analysis by polyacrylamide gel electrophoresis demonstrated that the amounts of major proteins in tear fluids, such as lactoferrin and secretory immunoglobulin A were not changed upon wearing contact lenses. In contrast, cellulose acetate membrane electrophoresis revealed that mucin band in tear samples from contact lens wearers showed significant decrease as examined by lectin staining.