Contact lens cast moulding.

摘要

Contact lens is cast by polymerising a monomer in a cavity between a male mould and a female mould. When the moulds are opened, the lens remains supported on the surface. Cover is sealed onto the flange to form a package. Lens is cast with the male mould (12) facing downwards and female mould, which has an annular wall and flange similar to the wall and flange (22), is fitted piston-like with the male mould. Cavity is sealed properly and that the moulds retract to take up shrinkage when the lens is polymerised in a pressure vessel at, e.g. 0.2-1 bar. Surface is flame polished to ensure that the lens remains attached to the male mould when the moulds separate. Male mould is then inverted to face upwards and form an open container. Saline fluid is poured into the container to hydrate and ease the lens from the mould. Finally a removable lid is applied to the flange.