Water-dissolved-oxygen permeability coefficients of hydrogel contact lenses and boundary layer effects

摘要: Oxygen permeability coefficients were determined for five types of commercial hydrogel contact lenses. For each type, the lenses used diverse thicknesses, and measurements done in distilled water physiologic salt solution, both at room temperature 37°C. The following tested: a hydroxyethyl methacrylate copolymer uncertain composition (Flexsol) about 31-34% hydration (observed DS = 1.3-2.3 X 104 μl (STP)-cm/cm2-h-mm Hg); cross-linked poly(hydroxyethyl methacrylate) (Soflens) 38-40% (DS 2.7-3.7 x 10-4, same units); glyceryl methyl methacrylates (CSI) 40.5-43.6% 2.4-3.8 with vinylpyrrolidone (HydroCurve I) 41-45% 2.06-4.65 (Sauflon) two hydrations, one 67-72% 9.5-17 units), other 77-81% 25-31 units). apparent oxygen increased lens thickness. This was interpreted as being caused by boundary layer resistances. hydrogels found to be dependent on content rather than chemical hydrogel. remain 37°C 23°C, due decrease rise temperature.