Identification of proteins in contact lens surface deposits by immunofluorescence microscopy

Worn soft contact lenses from five asymptomatic subjects were examined by immunofluorescence microscopy for type of protein on the lens surface. Lysozyme was the predominant protein component identified by this technique. IgA was also identified in deposits on all five lenses, but the staining was less intense than that for lysozyme. Lactoferrin was identified on the surface of four lenses, one of which stained intensely for this protein and three less intensely. IgG was identified on two contact lenses; the staining was less intense than that for lysozyme. New, never-worn soft contact lenses did not stain for any of the proteins examined in this study. We conclude that several normal tear proteins are capable of contributing to surface deposits on soft contact lenses, and all worn soft contact lenses have protein adherent to their surface as a result of normal wear.