The fluid content of hydrophilic contact lenses on the eye.
Hydroflex m, Hydroflex 72 and Sauflon PW lenses were tested (declared fluid content 38.4%, 72% and 79%, respectively). At room temperature in vitro the mean fluid content of Hydroflex m and Sauflon PW was significantly higher than declared (P less than 0.002), but this might be due to insufficient blotting of the lens surface. The mean fluid content of Hydroflex 72 was about 2.5% lower than declared (P less than 0.002). During wear the fluid content of Hydroflex m did not differ significantly from the in vitro recordings at room temperature, while the fluid content of worn Hydroflex 72 and Sauflon PW was about 2% lower than in vitro (P less than 0.002). This difference was mainly due to the greater temperature susceptibility of these lens materials. Apart from a slight decrease during the first few h after insertion (P less than 0.05), the fluid content of the lenses was not significantly influenced by the duration of wear. The mean contact lens surface temperature during wear was 30.7 degrees C.
D002986:Clinical Trials as Topic; D003263:Contact Lenses, Hydrophilic; D006801:Humans; D006863:Hydrogen-Ion Concentration; D011312:Pressure; D013696:Temperature; D013997:Time Factors; D014835:Volatilization