Carbohydrate deposits on the surfaces of worn extended-wear soft contact lenses.

Three different commercial extended-wear soft contact lenses worn continuously by patients for at least 28 days were stained with fluorescein isothiocyanate-labeled lectins. These lectins detected the presence of alpha-linked or beta-linked D-mannose, D-glucose, D-galactose, L-fucose, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, and N-acetyl neuraminic acid (sialic acid) on the surfaces of the contact lenses. These saccharides are bound to other sugars that likely account for an integral part of glycoprotein and/or glycolipid deposits on lens surfaces. These tear deposits may contribute to the chemical spoilage of the lens and, furthermore, may serve as specific receptors for pathogenic microorganisms commonly implicated in extended-wear soft contact lens-associated infectious keratitis.