| 摘要 |
PROBLEM TO BE SOLVED: To provide a multi-focal intraocular lens suitable for distant vision irrespective of the size of the pupil diameter, and also to provide a method for designing the multi-focal intraocular lens. SOLUTION: The multi-focal intraocular lens includes an optical section having a base curve for keeping a part of incident light collected at a predetermined distance focus by means of refractive power, a diffraction region which includes a plurality of diffraction gratings formed in a concentric manner on the whole surface of the lens surface forming the base curve of the optical section and keeps a part of the incident light collected at a predetermined near focus by diffraction of the plurality of diffraction gratings each of which has a step height determined by phase difference, and a holding section for fixing the optical section within the eye of a subject. In the intraocular lens, the step heights of all the diffraction gratings formed in the diffraction region are identical and the phase difference is set between 0.2 and 0.45 to distribute more incident light to the distance focus than to the near focus. COPYRIGHT: (C)2011,JPO&INPIT |
