The efficacy of hydrophilic contact lens cleaning systems in removing protein deposits

New, never-worn, individual hydrophilic contact lenses were incubated in an artificial tear solution (containing lysozyme, albumin, lactoferrin, and glycoprotein) for 24 hours at 37 degrees C with constant stirring. These lenses were then cleaned following the manufacturer's instructions with one of six commercial cleaning systems: AOSEPT, CONSEPT, Oxysept, ReNu, Opti-Free and thermal disinfection in conjunction with the Allergan Enzymatic Contact Lens Cleaner. The protein remaining on each lens after cleaning was removed and then quantified by the Bio-Rad Protein Assay. High resolution gel electrophoresis was used to assess the individual protein profile patterns. We found that only one-third to one-half of the protein deposited on a lens is removed by the above cleaning systems. Of the proteins in the artificial tear solution only lysozyme is removed by cleaning, while lactoferrin, albumin, and glycoprotein tend to remain on the lens. Since many of the complications experienced by contact lens wearers are thought to be related to protein deposits on their lenses, our results suggest the need for more effective contact lens cleaning solutions.