WO2000058774A1

WO2000058774A1 - Contact lenses

Info

Publication number: WO2000058774A1
Application number: PCT/US2000/005075
Authority: WO
Inventors: Timothy Clutterbuck
Original assignee: Johnson & Johnson Vision Care, Inc.
Priority date: 1999-03-26
Filing date: 2000-02-25
Publication date: 2000-10-05
Also published as: AR026114A1; AU3709800A

Abstract

The invention provides contact lenses that have a back edge designed so that the peripheral portion of the edge does not rest on the wearer's cornea.

Description

CONTACT LENSES

Field of the Invention

The invention relates to contact lenses. In particular, the invention relates to contact lenses that have a back edge designed so that the flat portion of the edge does not rest on the wearer's cornea.

Background of the Invention

The use of contact lenses for cosmetics and the correction of visual acuity is well known. Two major categories of contact lenses in use are the hard lens and the flexible, soft contact lens.

Contact lenses are subject to debris accumulation while in use. Debris removal, in part, is facilitated if the lens moves easily on the eye because such movement allows tear fluid to remove debris from under the lens. However, the design of the back surface edges of a conventional contact lens is flat, hindering movement of the lens on the eye. Additionally, the back surface edge of the lens may form a sharp edge that impinges on the conjuctival membrane, indenting and roughening the membrane. Thus, a need exists for a back surface design that permits tear movement, debris removal, and that does not impinge on the conjunctival membrane.

Brief Description of the Drawings

FIG. 1 is a magnified, cross-sectional view of a portion of the lens of the invention.

Detailed Description of the Invention and Preferred Embodiments

The invention provides contact lenses and methods for producing contact lenses, in which the back surface of the lens is designed so as to permit movement of the lens and tear flow between the lens' back, or concave, surface and the cornea.

Further, the back surface edge of the lens does not impinge on the conjunctival membrane.

In one embodiment, the invention provides a contact lens comprising, consisting essentially of, and consisting of a concave surface comprising, consisting essentially of, and consisting of a fillet and an edge flat. By "fillet" is meant a rounded junction between the back curve of the concave surface and the edge flat that is tangential to the back curve and edge flat. By "edge flat" is meant a flattened area connecting the back with the front surface of the lens.

It is a discovery of the invention that by the use of a fillet, the edge flat of the lens is lifted off of the cornea. Referring to Fig. 1, a portion of the lens of the invention is shown. Back surface 1 incorporates fillet 2 and edge flat 3 at its periphery to produce a rounded edge. Tear fluid easily enters underneath edge flat 3 and acts as a lubricant freeing the lens edge from the corneal surface and facilitating movement of the lens on the eye. Also, the shape of fillet 2 is such that is will not irritate the eye's surface. The use of an edge flat 3 also truncates the lens edge, eliminating any sharpness from the lens edge.

The back and front curves of the contact lenses of the invention may be of any configuration desired. For example, the surfaces may have any one or more of spheric, aspheric, bifocal, multifocal, multifocal-toric, prismatic, cylindric corrections, and combinations thereof. These corrections may be on either or both the convex or concave surface.

The fillet is rounded and has a radius of curvature of about 25 to about 500, preferably about 25 to about 250, more preferably about 50 to about 100 μm. The length of the fillet is about 15 to about 350, preferably about 15 to 100, more preferably about 20 to 50 μm. The edge flat length is about 10 to about 250, preferably about 10 to 125 μm, more preferably about 15 to 50 μm.

Contact lenses useful in the invention are soft lenses made of any material suitable for producing such lenses. The lenses of the invention may have any of a variety of corrective optical characteristics incorporated onto the surfaces. For example, the lens of the invention is a toric soft contact lens, meaning that the contact has a cylindrical optical surface, or power, to correct for the wearer's astigmatism.

The concave surfaces of the lenses of the invention may be formed by any convenient means. For example, an optical cutting tool with a numerically controlled lathe may be used to form a metallic optical tool incorporating the off- axis bevel of the invention. The tool is then used to make convex surface molds that are then used, in conjunction with concave surface molds, to form the lens of the invention using a suitable liquid resin placed between the molds followed by compression and curing of the resin.

It will be understood by those of ordinary skill in the art that various other changes of the details of the invention described may be made. Such changes are intended to be included within the scope of the invention claimed.

Claims

What is claimed is:

1. A contact lens comprising a concave surface and a convex surface, the concave surface comprising a fillet and an edge flat.

2. The lens of claim 1, wherein the fillet and edge flat are at the periphery of the concave surface.

3. The lens of claim 1, wherein the contact lens is a soft contact lens.

4. The lens of claim 1, wherein the fillet radius of curvature is about 25 to about 500 μm and the fillet length is about 15 to about 350 μm.

5. The lens of claim 4, wherein the edge fiat length is about 10 to about 250 μm.

6. The lens of claim 1, wherein either or both the concave and convex surface have configuration selected from the group consisting of spheric, aspheric, bifocal, multifocal, multifocal-toric, prismatic, cylindric corrections, and combinations thereof.

7. The lens of claim 4, wherein either or both the concave and convex surface have configuration selected from the group consisting of spheric, aspheric, bifocal, multifocal, multifocal-toric, prismatic, cylindric corrections, and combinations thereof.

8. The lens of claim 5, wherein either or both the concave and convex surface have configuration selected from the group consisting of spheric, aspheric, bifocal, multifocal, multifocal-toric, prismatic, cylindric corrections, and combinations thereof.