A progressive multifocal contact lens suitable for compensating presbyopia where the power of the optical zone vaires in part with respect to the base dioptric power

摘要

A progressive multifocal contact lens is suitable for compensating presbyopia. The contact is characterized in that the power of the optical zone varies in part with respect to the base dioptric power between the centre of the lens and the periphery of the optical zone according to a progression presenting: a peak at the centre, from which there departs a first tract that rapidly descends to the base dioptric power and along which the lens functions for near vision, an intermediate second tract substantially parallel to the abscissa at the value of the base dioptric power and along which the lens functions for far vision and a peripheral third tract consisting of a progressively rising first part and of a second part parallel to the abscissa. The two parts correspond to the powers at which the lens functions progressively for intermediate distances in the first part and in a constant manner for near vision in the second part.