PROGRESSIVE MULTIFOCAL LENS FOR SPECTACLES

摘要

PROBLEM TO BE SOLVED: To provide a progressive multifocal lens for spectacles which has wide near sight and intermediate visual field region at an admission rate of refracting power of >=2.5 and has a uniform distribution of spherical surface values and cylinder values. SOLUTION: This lens has a far sight visual field region (VL), the near sight visual field region (VP), the intermediate visual field region, a progressive main meridian passing these three regions and a mounting center (CM). The far sight visual field region includes an angle sector of 110 deg. in central angle of which the apex exists at the mounting center. The spherical surface value and cylinder value thereon are <=0.50 dioptry. The region of the lens extending to the center of the intermediate visual field region on the reference point of the near sight visual field region is limited to <=0.30 dioptry. The maximum fluctuation rate of the cylinder value to both ends of the meridian restricted to <=10% of the admission rate of the refracting power of the lens is 20 mm.