Power glass for correcting presbyopia, has middle part with varying refraction power, where glass belongs to series of glasses having common spherical refraction power and different base curves

摘要

The glass (10) has front and back surfaces comprising a long distance vision part and a near vision part, and middle part having refraction power that varies between the refraction power of the long distance part and the near vision part. The glass is taken randomly from a series of glasses that have a common spherical refraction power that is more than or equal to one and different base curves.