Optics: eye examining – vision testing and correcting – Spectacles and eyeglasses – Ophthalmic lenses or blanks
Reexamination Certificate
2000-08-15
2002-09-24
Schwartz, Jordan M. (Department: 2873)
Optics: eye examining, vision testing and correcting
Spectacles and eyeglasses
Ophthalmic lenses or blanks
C351S16000R, C351S177000
Reexamination Certificate
active
06454409
ABSTRACT:
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 conjunctiva. The lenses of the invention exhibit good lens handling as well as excellent on-eye comfort and movement.
BACKGROUND OF THE INVENTION
The use of contact lenses for cosmetic effect and the correction of visual acuity is well known. One disadvantage of contact lenses is that they 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 most conventional contact lenses is flat, hindering movement of the lens on the eye. Additionally, the back surface edge of these conventional lenses may form a sharp edge that impinges on the conjuctival membrane, indenting and roughening the membrane.
One lens design, disclosed in U.S. application Ser. No. 09/277,464 incorporated herein in its entirety by reference, permits tear movement, debris removal, and does not impinge on the conjunctival membrane. Such a lens design, an edge-off-eye design, is depicted in
FIG. 1
in a magnified, cross-sectional view that incorporates a fillet and 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.
Referring to
FIG. 1
, back surface
1
incorporates fillet
2
and edge flat
3
at its periphery to produce an edge-off-eye lens edge. This edge design permits lifting of the edge apex off of the ocular surface 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.
Although the edge-off-eye design represents an improvement compared to conventional lens designs, problems with conjunctival indentations, and less than desirable on-eye movement can occur with edge-off-eye lenses. Thus, a need exists for an improved edge-off-eye lens.
REFERENCES:
patent: 4165158 (1979-08-01), Travnicek
patent: 4239353 (1980-12-01), Koller
patent: 4463148 (1984-07-01), Hofer et al.
patent: 4561737 (1985-12-01), Bourset et al.
patent: 5069542 (1991-12-01), Hofer et al.
patent: 5452031 (1995-09-01), Ducharme
patent: 5483304 (1996-01-01), Porat
Merriam Webster's Colleguate Dictionary (10th ed 1997), p. 109.
Harodl A. Stein, Bernard J. Slatt, and Raymond M. Stein, Ophthalmic Terminology:Speller and Vocabulary Builder (3d ed 1992), p. 103.
Graeme Young, Soft Lens Fitting Reassessed, Spectrum 1992 pp. 56, 57, 60, 61.
Malcolm M. Bibby & Alan Tomlinson, A Model to Explain the Effect of Soft Lens Design Specifications on Movement, American Journal of Optometry & Physiological Optics, Apr. 1983, vol. 60, No. 4, pp. 287-291.
Nathan Efron and Jan Veys, Defects in Disposable Contact Lenses Can Comprise Ocular Integrity, International Contact Lens Clinic, Jan. Feb. 1992, vol. 19 No. 1&2, pp. 8-18.
Graeme Young et al., Influence of Softcontact Lens Design on Clinical Performance, Optometry & Vision Science, vol. 70, No. 5, pp. 394-403, 1993.
Mark J. Roseman, Effects of Base Curve on the Fit of Thin, Mid-Water Contact Lenses, International Contact Lens Clinic, vol. 20, May/Jun. 1993, pp. 95-101.
Gerald E. Lowther et al., Critical Base Curve and Diameter Interval in the Fitting of Spherical Soft Contact Lenses, American Journal of Optometry & Physiological Optics, May 1981, vol. 58, No. 5, pp. 355-360.
Malcolm M. Bibby, Sagittal Depth Considerations in the Selection of the Base Curve Radius of a Soft Contact Lens, American Journal of Optometry & Physiological Optics , Jul. 1979, vol. 56, No. 7, pp. 407-413.
Armitage Brian S.
Clutterbuck Timothy A.
Lorenz Kathrine Osborn
Orr Susan B.
Gianneschi Lois
Johnson & Johnson Vision Care Inc.
Schwartz Jordan M.
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