Patent ID: 8999209
Filing Date: 2015-04-07
Classification: B29D,G01M

Abstract:
1. A method of measuring an axis angle of a tonic contact lens including a posterior tonic central zone having a cylindrical axis, and an anterior lens surface forming a ballast that has an axis of orientation offset from the cylindrical axis at a selected rotational angle, the method comprising: (a) providing anterior and posterior mold sections including respective anterior and posterior mold cavity defining surfaces, wherein the posterior mold cavity defining surface includes a tonic central zone and the anterior mold cavity defining surface is shaped to provide the ballast, the mold sections being alignable at multiple rotational positions; (b) providing a detectable feature on each of the anterior and posterior mold sections at a predetermined angular location with respect to the tonic and ballast axes thereof, respectively; (c) charging the anterior mold section with a predetermined quantity of a polymerizable lens-forming monomer mixture; (d) rotating the detectable feature of the posterior mold section to a predetermined position relative to the detectable feature of the anterior mold section, wherein the detectable feature of the anterior mold section is a zero reference, and wherein the step of rotating the detectable feature of the posterior mold section is carried out after charging the anterior mold section with the predetermined quantity of the polymerizable lens-forming monomer mixture; (e) assembling the anterior and posterior mold sections while maintaining the corresponding rotational position; and (f) measuring the axis angle between the detectable feature of the posterior mold section relative to the detectable feature of the anterior mold section, wherein the step of measuring the axis angle is carried out prior to curing of the polymerizable lens-forming monomer mixture.