Method and apparatus for tinting hydrogel soft contact lens

摘要

The apparatus comprises a base 12 supporting a mandrel 13 having a curved upper surface 14, a support member 16 adapted to be attached to the base, a screen stencil mask 20 for support by the support member, the support member 16 including a central blocking member 17 for covering and engaging the effective central area of the screen mask, and a peripheral blocking member 19 for engaging the mask in an annulus around the central blocking member. An opening between the blocking members allows liquid 25 to be introduced onto the screen mask when supported on the support. The screen mask in the annulus has a stencil pattern to be marked on the substrate. Biasing means 15 are shown. An opaque coating is applied to an iris area of a contact lens using barium chloride followed by aqueous sulphuric acid.