Average Thickness of a Hydrogel Lens for Gas Transmissibility Calculations

Several attempts have been made to calculate the average thickness of hydrogel lenses for the purpose of calculation of oxygen transmissibility. The deficiencies of these equations are discussed and a new equation is given. Results of average thickness calculations with variation in different parameters are presented. These results indicate that the effect of thickness variation in higher powered lenses has been seriously underestimated. The parameters which cause a major difference in the average thickness compared to the center thickness are power, chord radius, and water content.