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US 6,183,083 B2Granted
Contact lens comprising a violet tint
AssigneeWesley-Jessen Corporation
InventorGerardo J. Ocampo
Life of this patent
Estimating the term…
Abstract
Adding a small quantity of a violet colorant to a contact lens material provides a clear contact lens that has no apparent undesirable yellow tint, such as caused by a UV-absorbing compound. Further, the violet colorant can also be used with a colored lens, in the absence of the handling tint, to mask any undesirable yellow tint, such as that produced by a UV-absorbing compound. The violet colorant will not unacceptably alter the modifying color of the colored lens.
Claims6
A colored contact lens comprising:
- (a) a pattern of modifying color elements on a surface of the lens over a region of the lens that substantially covers the iris;
- (b) a UV absorbing compound present in an amount at least about 0.9 wt % dry basis that would be sufficient to cause a noticeable yellow tint in a conventional clear contact lens;
- and
- (c) an amount of violet colorant between 0.0001 wt % and 0.01 wt % dry basis sufficient to mask the yellow tint, but less than an amount of violet colorant necessary to interfere with the modifying color and cause a darker appearance to the lens conventionally associated with violet colorants, whereby the modified color of the wearer's eye as observed by an ordinary wearer is cosmetically indistinguishable from a similar lens not having the UV absorbing compound and violet colorant.
1 more element
A method of making UV-absorbing contact lenses comprising the steps of:
- a) adding a UV-absorbing compound to a contact lens formulation in an amount at least about 0.9 wt % dry basis sufficient to absorb UV light and cause a yellow tint;
- b) titrating the contact lens formulation containing the UV-absorbing compound and determining the amount of violet colorant to be added;
- c) adding violet colorant to the formulation in an amount between about 0.0001 wt % and 0.01 wt % dry basis sufficient to mask the yellow tint caused by the presence of the UV-absorbing compound;
- and
- d) polymerizing the formulation and forming the polymer into contact lenses.
2 more elements
Dependencies are inferred from the claim text.