PURPOSE. To examine the spoilation profiles of two extended wear contact lens materials. METHOD. The spoilation profiles of Focus Night & DayÔ and PurevisionÔ lenses worn for 30 nights or for four 6-night periods continuously, were assessed using fluorescence spectrophotofluorimetry and ultra violet spectroscopy. Information was obtained on surface and lipid deposition on the front and back of the lens, as well as total protein uptake. Extracted lipids were analysed by high performance liquid chromatography. Absorption into the contact lens matrix was also assessed using plasma emission and monitoring.
RESULTS. The two extended wear materials showed no significant difference in surface deposited protein. There was a measureable difference in absorbtion of protein into the lens matrix, however. Additionally, the level of surface lipid deposition showed a significant material dependence and the two lens types behaved quite differently from each other in this respect. These patterns of deposition were not found to vary significantly between the two wear patterns examined.
CONCLUSIONS. The differences in lens chemistry and surface treatment did not lead to differences in the pattern or level of surface deposition of protein betweeen the two extended wear lenses. In all other respects the spoilation behaviour of the two lens types did differ, however. The most significant difference was observed in the response of the lens materials to lipid and there was an observable difference in the tendency of protein to penetrate the lens matrices. Individual patients consistently showed left to right eye variability in addition to front and back surface deposition variability. Lipid profiles were much more patient dependent than protein deposition, but still driven by material/surface considerations.