Soft toric contact lens

• US 4,508,436 A
• Filed: 09/28/1981
• Issued: 04/02/1985
• Est. Priority Date: 09/28/1981
• Status: Expired due to Fees

• Current Assignee: Vistakon, Inc. (Johnson & Johnson)
• Original Assignee: Frontier Contact Lenses of Florida Incorporated
• Inventors: Sitterle, George
• Primary Examiner(s): Corbin, John K.
• Assistant Examiner(s): Sugarman, Scott J.
• Application Number:
  US06/306,438
• Time in Patent Office: 1,282 Days
• Field of Search: 351/160 H, 351/160 R, 351/161
• US Class Current: 351/160.00H
• CPC Class Codes: G02C 7/04 Contact lenses for the eyes disinfection or sterilisation of contact lenses A61L12/00
• CPC Class Codes: G02C 7/048 Means for stabilising the orientation of lenses in the eye

Abstract

A soft toric contact lens having spherocylindrical power for correcting astigmatism in humans and utilizing a prism ballast as a means of maintaining correct axial orientation. The degree of prism is greater than 1.0 diopter, and the peripheral outer surface of the lens is tapered off to a relatively thin edge of constant thickness over a substantial portion of the ballast area.

Claims

1. A soft toric contact lens of spherocylindrical power having a concave inner surface, a convex outer surface, a horizontal axis and a vertical axis;

said outer surface having a central optical zone and a peripheral lenticular zone;

said lens including a prism ballast in the vertical axis, the degree of prism being greater than about 1.0 diopter;

the outer surface of said lens having a smoothly beveled, tapered-off region in the lenticular zone in the area of maximum ballast, the edge of said lens having a substantially uniform thickness in said tapered-off region.

2. The soft contact lens of claim 1 wherein said tapered off region is crescent-shaped.

3. The soft contact lens of claim 1 wherein said concave inner surface is spherical and said convex outer surface is toric.

4. The soft contact lens of claim 1 wherein the orientation of said spherocylindrical power is in the vertical axis, and said tapered-off region is crescent-shaped and symmetrical about said vertical axis.

5. The soft contact lens of claim 1 wherein the orientation of said spherocylindrical power is at an angle to the vertical axis, and said tapered-off region is crescent-shaped and nonsymmetrical about said vertical axis.

6. The soft contact lens of claim 1 wherein the degree of prism is about 1.5 diopters.

7. The soft contact lens of claim 1 wherein said tapered-off region extends radially at least about 50 percent into said lenticular zone.

8. The soft contact lens of claim 1 wherein said tapered-off region extends radially from about 50 percent to about 75 percent into said lenticular zone.