Patent ID: 7650250

Claim:
A method for determining whether a lens manufacturing process is in control, the method comprising the steps of: (a) providing from a lens manufacturer to an independent testing laboratory a first plurality of lenses, (b) having the independent testing laboratory determine the mean fracture height of the first plurality of lenses using an impact resistance testing device to establish a baseline fracture height; (c) providing from the lens manufacturer to the independent testing laboratory a second plurality of lenses, the second plurality containing fewer lenses than the first plurality; (d) having the independent testing laboratory determine the mean fracture height of the second plurality of lenses using an impact resistance testing device; (e) calculating the difference between the baseline fracture height and the mean fracture height of the second plurality of lenses; and (f) determining that the lens manufacturing process is in control if the difference is below a threshold value and not in control if the difference is above or equal to the threshold value, wherein the first plurality consists of about 50 to about 60 lenses, and the second plurality consists of about 10 to about 15 lenses.