(under subclass 168) Subject matter wherein multiple lens elements of different refractive indices have their adjacent surfaces joined together to provide a unitary multifocal lens that has, for example, a long vision and a reading section.
(1) Note. The modification here comprises for example a major glass member having a shallow countersink and a relatively thin segment fused therein, a thin reading segment fused to a major glass surface, or the lens members may be held in place by usual frame pieces. The countersinks and segments may be of different dimensions and shapes.
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168, for multifocal lenses may from a single piece of glass; and 171, for multiple element lenses with three or more foci.