Quantification of individual proteins in silicone hydrogel contact lens deposits

Purpose: The aim of this study was to quantify specifc proteins deposited on daily wear silicone hydrogel lenses used in combination with multipurpose disinfecting solutions (MPDSs) by applying multiple-reaction-monitoring mass spectrometry (MRM-MS). Methods: Balaflcon A or senoflcon A contact lenses used with different MPDSs on a daily wear schedule were collected. Each worn lens was extracted and then digested with trypsin. MRM-MS was applied to quantify the amounts of lysozyme, lactoferrin, lipocalin-1, proline-rich protein-4, and keratin-1 in the extracts. Results: The amount of protein extracted from the contact lenses was affected by the individual wearers, lens material, and type of care system used. Higher amounts of proteins were extracted from lenses after wear when they were used with an MPDS containing polyhexamethylene biguanide (PHMB) and poloxamer 407 compared with MPDSs containing polyquaternium-1 (PQ-1)/alexidine dihydrochloride with Tetronic 904 or PQ-1/ PHMB with poloxamine and sulfobetaine (p<0.05). There was a correlation between the amount of lipocalin-1 or keratin-1 extracted from lenses and symptoms of ocular dryness. Conclusions: The MRM-MS technique is a promising approach that could be used to reveal associations of individual proteins deposited on lenses with performance of contact lenses during wear.