In this study, the oxygen permeabilities and diffusion rates of several soft contact lenses were measured and compared. The hydrophilic contact lenses used in this experiment were composed ,of four different types, 27, 32, 48 and 70 per cent of water content, respectively.
Oxygen permeability rates were determined by using oxygen diffusion apparatus composed of two chamber diffusion system under a partial pressure gradient of approximately 5 : 1. Serial samples of 1 ml were removed from the each chamber at 30 minutes interval and the Po2 in the samples was measured on a blood gas analyser.
The oxygen flow rates of four different soft contact lenses varied from 99.8?1/cm2/hr to 292. 1 1/cm2/hr, depending upon their water contents. .
The permeability characteristics was affected by the state of hydration of lens and the comparison of the oxygen flow rates showed that even the least permeable soft contact lens in this study was able to meet the corneal oxygen requirement.
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