Toric lens manufacture

A method of cast moulding toric contact lenses in which each lens has a ballast and a toric central zone having a cylindrical axis, the cylindrical axis having an axis of orientation at a desired rotational angle with respect to the axis of the ballast, said method comprising the steps of:

• providing sets of male and female mould halves (31, 32) wherein the surface of one mould half of each set defines said cylindrical axis and the surface of the other mould half of each set defines said ballast axis, introducing a flowable polymerisable composition into the female mould halves and closing the associated male mould halves fully into the female mould halves and curing the polymerisable composition to form toric contact lenses;
• characterised by loosely assembling the sets of mould halves each in a relative position corresponding to the rotational angle of the majority of lenses to be moulded
• transporting the loosely assembled sets of mould halves to a filling station (10, 11), where the flowable polymerisable composition is introduced to the female mould halves, under conditions in which the mould halves of each set are free to move relatively to each other in a rotational sense and the sets are subjected to a deliberate joggling action to ensure the mould halves of the sets assume relative orientations approximately corresponding to a guassion distribution curve during said transport or while being held prior to entry into the filling station and
• sorting the lenses into groups of lenses having the same or similar rotational angles.