Lipid deposition on silicone hydrogel lenses, part I: quantification of oleic Acid, oleic Acid methyl ester, and cholesterol.
PURPOSE: To investigate the sorption of oleic acid, oleic acid methyl ester, and cholesterol on currently marketed silicone hydrogel contact lenses. METHODS: Two liquid chromatography methods were developed and used to analyze lens extracts from continuous-wear and daily-wear modalities from asymptomatic silicone hydrogel contact lens wearers. RESULTS: Of the three probed compounds, cholesterol is the most prevalently sorbed, at levels ranging from below the limit of quantitation (<1.50 microg per lens) to approximately 37.0 microg per lens. Oleic acid and oleic acid methyl ester were found to exist at levels below the limit of quantitation (<1.50 microg per lens). In general, there appears to be no significant difference between the amounts of cholesterol sorbed on the continuous-wear PureVision and daily-wear PureVision lenses evaluated. CONCLUSIONS: The quantities of lipid sorbed to continuous-wear PureVision lenses are significantly different from those previously reported by other authors in a similarly conducted experiment. This difference suggests that any hypothesis of silicone hydrogel lenses based on these previous lipid data should be reconsidered.