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US 5,309,187 AGranted
High magnification ophthalmic lens
AssigneeOcular Instruments, Inc.
InventorsJanet L. Crossman, Phillip J. Erickson, Gregory L. Heacock, Martin A. Mainster
Life of this patent
Estimating the term…
Abstract
An ophthalmic lens having two elements, a contact lens and an entry lens. The lens produces a magnified aerial image of the fundus of the eye, and can also be used for laser delivery to the fundus. The lens is particularly useful because it provides high magnification and detail of the fundus as well as excellent steroscopic field.
Claims19
A magnifying ophthalmic lens for observing the fundus of the eye and for delivering laser energy thereto comprising:
- a contact lens having a posterior surface and an anterior surface, said posterior surface having a curvature compatible with the anterior surface of a cornea, the anterior surface of the contact lens having a predetermined curvature wherein the indices of refraction of said contact lens can range from 1.47 to 1.85, and the axial thickness of the contact lens (T.sub.C) can range from 1 mm to 12 mm, and
- an entry lens positioned anterior to the contact lens, the entry lens being aspheric, the surfaces of the entry lens being defined by the formula:
- ##EQU3## wherein C=(1/R),
- E=b+1, and
- K.sup.2 =X.sup.2 +Y.sup.2,
- wherein for the anterior surface of the lens,
- R.sub.2EL ranges from 20 mm to 90 mm and
- b.sub.2EL ranges from 7.0 to -4.0, and
- wherein for the posterior surface of said lens,
- R.sub.1EL ranges from 10 mm to 50 mm, and
- b.sub.1EL ranges from 0 to -4.0,
- said entry lens having a thickness (T.sub.EL) ranging from 6 mm to 14 mm, wherein said entry lens has an index of refraction ranging from 1.47 to 1.85, the optical axes of the contact lens and the aspheric lens being substantially coincident, the entry lens collecting the light rays emerging from the contact lens and producing an aerial image anterior to the entry lens, the contact lens and the entry lens element being positioned relative to each other and having their curvatures chosen such that light rays originating on the fundus of the eye are magnified in the aerial image produced by the entry lens, at a magnification greater than 1.0.times..
9 more elements
An ophthalmic lens for viewing the fundus comprising:
- (a) a contact lens having a posterior surface with a curvature compatible with the cornea of an eye and being positionable in mutually opposing contact relationship with said cornea, and an entry lens, said lenses being aligned along their respective optical axes, said lenses being constructed when said contact lens is in contact with the cornea to gather light rays from the fundus and focus them in a magnified aerial image anterior to said entry lens, the magnification being in the range of 1.0.times. to 1.5.times..
An othalmic lens for viewing the fundus comprising:
- (a) a contact lens having a curvature compatible with the cornea of an eye and being positionalbe in mutually opposing contact relationship with said cornea, and an entry lens, said lenses being aligned along their respective optical axes, said lenses being constructed when said contact lens is in contact with the cornea to gather light rays from the fundus and focus them in a magnified aerial image anterior to said entry lens, said lens being constructed so that the aerial image is formed less than 55 mm from the anterior surface of the cornea when said contact lens is in contact with the cornea, the magnification being in the range of 1.0.times. to 1.5.times..
An ophthalmic lens for viewing the fundus comprising:
- (a) a contact lens having a curvature compatible with the cornea of an eye and being positionable in mutually opposing contact relationship with said cornea, and an entry lens, said lenses being aligned along their respective optical axes, said lenses being constructed when said contact lens is in contact with the cornea to gather light rays from the fundus and focus them in a magnified aerial image anterior to said entry lens, the magnification being in the range of 1.1.times. to 1.5.times., and having a binocular field of view on the order of.+-.37.5.degree. and a stereoscopic field of view on the order of.+-.21.5.degree., measured from the optical axes.
Dependencies are inferred from the claim text.