25062129
OBJECTIVE	The purpose of the study was to measure contact lens lipid spoliation of silicone hydrogel PureVision ( balafilcon A ) and hydrogel Acuvue 2 ( etafilcon A ) contact lenses worn for 10 hours single use ( DD ) and 7 days of extended wear ( EW ) .
METHODS	Two similar study populations ( DD , n = 55 ; EW , n = 53 ) , were enrolled at four study sites .
METHODS	In each population , a bilateral , randomized , crossover ( lens material ) , subject-masked experimental design was followed .
METHODS	Worn contact lenses were analyzed for lipid uptake using high-performance liquid chromatography by two laboratories : Alcon Laboratories ( right lens total uptake ) and OTG Research & Consultancy ( left lens total uptake and individual lipid classes ) .
RESULTS	Lipid uptake was different for the two materials : total lipid ( p < 0.007 ) , cholesterol esters ( p < 0.001 ) , cholesterol ( p < 0.001 EW only ) , and triglycerides/phospholipids ( p < 0.001 ) were higher for balafilcon A , whereas fatty acid ( p < 0.0025 EW only ) was higher for etafilcon A.
RESULTS	The ratio of the extracted lipids was also different : higher percentages of triglycerides/phospholipids ( p < 0.001 ) and cholesterol ( p < 0.001 EW only ) for balafilcon A and higher percentages of fatty acids/di - and monoglycerides ( p < 0.014 ) for etafilcon A.
CONCLUSIONS	Total lipid uptake was highly material dependent .
CONCLUSIONS	Both laboratories measured a greater uptake of lipids by the silicone hydrogel than the hydrogel material , a difference that was evident after only 10 hours of DD .
CONCLUSIONS	Total lipid uptake was greater after 7 days of EW compared with 10 hours of DD .
CONCLUSIONS	Of interest for contact lens spoliation and its avoidance was the differential lipid uptake profile , indicating material selectivity .
CONCLUSIONS	Whereas greater differentiation between materials was possible after 7 days of EW for each material , the lipid uptake profile was similar for DD and EW , indicating a greater material effect than a wear modality effect .

