Toric contact lens with axis offset compensation and method of manufacturing same

摘要

A contact lens and a method and apparatus for manufacturing a contact lens having areas of different thickness, the contact lens being compensated for differential shrinkage during the manufacturing process. The angular offset of the cylinder axis due to differential shrinkage is compensated for by introducing an equal and opposite offset during the manufacturing process. The axis offset caused by a particular manufacturing process is experimentally determined, i.e., for each intended cylinder axis, the corresponding offset (in terms of degrees of rotation) is determined. The lens compensation is implemented by adjusting the manufacturing process so that upon curing the lens corresponds to the desired, prescribed lens, without any axis offset.