اپتیک عدسی داخل چشمی چند کانونی تفرقی

The diffractive multifocal IOL provides simultaneous bifocal imaging by utilizing both diffractive and refractive optics. In both distant and near vision, there is a clear highly focused image on the retina. The second image is highly defocused, providing only faint background illumination. A small amount of the light goes to the higher orders of diffraction which are not perceptible by eyes. The bright spot produced by a zone plate is so intense that the plate acts much like a converging lens. There are also fainter images corresponding to focal lengths f/3, f/5, f/7, ...