Should Manufacturer Take The Oxygen Permeation Properties Into Consideration When Changing The Center Thickness Of Soft Contact Lenses?

Yes. The oxygen permeation properties of soft contact lenses include two indexes: oxygen permeability Dk and oxygen transmissibility Dk/t, and the latter is directly related to the thickness of the lens. Therefore, when changing the center thickness of the lens, the manufacturer should consider the effect of the change in thickness on properties of the lens to note whether the change in thickness has led to changed nominal value of the oxygen transmissibility Dk/t. If it is necessary to modify such nominal value, the administrative counterpart should submit corresponding test report as supporting data, as well as the basis for determining such nominal value of oxygen transmissibility Dk/t. Meanwhile, the relevant risk analysis should be conducted and verification data should be provided as needed.