摘要 |
A method is disclosed for constructing a glass mould, and particularly the primary glass mould member, for use in casting multifocal, ophthalmic lenses from organic polymers. The method comprises pressing a glass segment (60) with a cavity (62), removing the base portion (66) of the segment to form a perforation, mounting the perforated segment (70) in a counter-sink (84) on a second glass body (82), and fusing the assembly to form a blank for finishing. For trifocal lenses, a composite, perforated segment (120) is formed and sealed in a counter-sink (132) to form a blank. |