Abstract
s / Contact Lens & Anterior Eye 38 (2015) e13–e46 e21 Results: Relative rates of bulk dehydration (RBD) were calculated as available water lost per minute and plotted against time to provide a rate profile of lens water loss behaviour. Profiles were observed to be characteristic of the hydrophilic monomers in the polymer. In the early stages of water loss polyHEMA and HEMA-PC materials showed higher relative rates of dehydrationwith steeper profiles than did HEMA-NVP hydrogels. Peak rates for polymacon, omafilcon A and hilafilcon B were 0.50±0.08 RBD, 0.34±0.02 RBD and 0.27±0.01 RBD respectively (±SD). Conclusions: Although lenses of similar water contents behave similarly in terms of long-term cumulative water loss, the dynamics of water loss behaviour are material-specific. Some materials have relatively flat initial profiles whereas others have steep initial water loss-probably related to water binding characteristics of the polymer. It is logical to expect that flatter loss profiles would be associated with less dehydration during lens handling and insertion, which is the subject of ongoing exploration. Thomas Minchington, B.Sc. Biomedical Science, is a PhD student in the Biomaterials Research Unit at Aston University. He is currently researching the improvement of comfort in silicone and conventional hydrogel materials through the use of bound or sustained release additives. http://dx.doi.org/10.1016/j.clae.2014.11.021
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call