In vivo dehydration of silicone hydrogel contact lenses

Purpose. To benchmark the performance of new-generation silicone hydrogel contact lenses in terms of their in vivo hydration characteristics and to highlight the possible clinical ramifications of any changes observed. Methods. Thirteen subjects (four men and nine women with a mean age of 24.8 ± 5.0 years) wore a silicone hydrogel lens (PureVision, Bausch & Lomb, Rochester, NY) in one eye and a conventional hydrogel lens (ACUVUE 2, Johnson & Johnson Vision Care, Jacksonville, FL) in the other eye for 4 weeks on an extended-wear basis. A gravimetric method was used to determine lens water content and dehydration during the intended lifespan of the lenses. Results. For the PureVision lens, the water content was 38.3% ± 0.9%, 35.2% ± 1.1%, and 35.3% ± 1.7% at baseline and after 2 and 4 weeks of wear, respectively (F=28.4, P