Gasket for casting lenses

A lense casting cell comprising the combination of:

• an annular resilient gasket having a radially inwardly directed generally T-shaped cross-sectional configuration, the inner most side of which provides a wall of a casting cavity within said cell;
• a pair of mold halves, one positioned against each of opposite sides of said gasket in adjoining relationship with said wall of said cavity, and.
• said gasket having an approximately intermediately disposed external slot extending about a major position of the circumference of said gasket and extending radially inwardly toward said wall of said casting cavity for enhancing the flexibility of said gasket in the functional area thereof adjacent to said wall.