Patent ID: 6197227
Filing Date: 2001-03-06
Classification: B29D,Y10S

Abstract:
A method for molding toric contact lenses having opposite anterior and posterior optical surfaces, said toric lenses further including a toric axis and a ballast axis formed on said opposite optical surfaces thereof, respectively, including automatically and selectively establishing any one of a plurality of predetermined axial offsets, between 0 degrees and 180 degrees, between said toric axis and said ballast axis of said lenses, said method comprising the steps of:a) providing anterior and posterior mold sections having anterior and posterior mold surfaces, respectively, said toric axis formed on one of said anterior and posterior molding surfaces, and said ballast axis formed on the other of said anterior and posterior mold surfaces, said anterior and posterior mold surfaces forming said anterior and posterior optical surfaces of said lenses, respectively;b) providing a detectable feature on each of said anterior and posterior mold sections at a predetermined angular location with respect to said toric and ballast axes thereof, respectively;c) providing a toric axis alignment tool having bottom and top sections and including means for detecting and locating said detectable features on each of said anterior and posterior mold sections at known angular positions upon engaging said anterior and posterior mold sections with said bottom and top sections of said axis alignment tool, respectively, and simultaneously rotating said anterior and posterior mold sections relative to said toric axis alignment tool;d) releasing said anterior and posterior mold sections from said axis alignment tool while maintaining said known angular positions of said anterior and posterior mold sections;e) rotating at least one of said anterior and posterior mold sections to establish said predetermined axial offset between said toric axis and said ballast axis;f) charging said anterior mold section with a predetermined quantity of liquid lens material;g) capping said posterior mold section on said anterior mold section with a predetermined clamping pressure, thereby forming a mold chamber between said anterior and posterior mold surfaces; andh) curing said liquid lens material in said mold chamber, thereby forming said toric lens having said toric and ballast axes formed on said opposite optical surfaces thereof at said predetermined axial offset.