US Patent 11427685 Method for making silicone hydrogel contact lenses

The invention provides a method for making silicone hydrogel contact lenses. The method of the invention is characterized by using an organic solvent as a processing-aid tool for controlling lens diameter without significantly affecting lens equilibrium water content during cast-molding of soft contact lenses from a polymerizable composition. By adjusting the weight percentage of the organic solvent in a polymerizable composition for making SiHy contact lenses, one can adjust lens diameter of produced SiHy lenses to meet target without affecting adversely the lens properties.