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1. WO1991006240 - SYSTEME DE LENTILLES DE CONTACT DIAGNOSTIQUES POUR OPHTALMOSCOPIE INDIRECTE

Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

[ EN ]

WHAT IS CLAIMED IS:

1. An indirect ophthalmoscopy contact lens used to observe the fundus of the eye comprising,
a holding means to support and position a
plurality of lenses relative to one another,
said plurality of lenses including a contact lens element having a concave posterior surface and convex anterior surface, whereinat least said anterior surface is an aspheric surface of revolution, and
at least one anterior lens element having first and second convex surfaces wherein said first and second convex surfaces are surfaces of revolution,
said contact element and at least one anterior element being positioned relative to one another and acting in conjunction with one another to refract light rays from a biomicroscope illumination system to form a sharply defined and distortion free image of the
biomicroscope light source aperture onto the fundus of an examined eye and to collect light rays emerging from the fundus of the eye and refracting said emerging light rays to form an aerial image of the fundus anterior to said at least one anterior element with said image being
substantially free of optical aberrations.
2. The indirect ophthalmoscopy contact lens of claim 1 wherein,
said concave posterior surface of said contact element is an aspheric surface of revolution which is substantially the shape of the anterior surface of the cornea of the eye to which the contact element is
applied.
3. The indirect ophthalmoscopy contact lens of claim 2 wherein,
said aspheric posterior surface of said contact element has a continuous and progressive reduction in curvature peripheralward with a peripheral slope equal to or less than that of an average cornea at an equivalent dismeter thereby minimizing localized peripheral lens bearing during translational movement of said contact element on the cornea.
4. The indirect ophthalmoscopy contact lens of claim 1 wherein,
said anterior surface of said contact element has an apical radius of curvature in the range from 3.5mm to 9.0mm and has a diameter in the range from 6.0mm to
16. Omm.
5. The indirect ophthalmoscopy contact lens of claim 1 wherein,
said anterior surface of said contact element has an apical eccentricity in the range from 0.05 to 1.4.
6. The indirect ophthalmoscopy contact lens of claim 1 wherein,
said first and second convex surfaces of said at least one anterior lens element are aspheric surfaces of revolution having an apical radius of curvature in the range from 5.0mm to 70.0mm and an apical eccentricity in the range from 0.7 to 4.0 eccentricity units.
7. The indirect ophthalmoscopy contact lens of claim 6 wherein,
the apical radius of curvature for each of the first and second convex surfaces of said at least one anterior lens element form a reciprocal relationship with each other ranging from 0.588 to 1.7 times the apical radius of curvature, of the opposite surface of said anterior lens element.
8. The indirect ophthalmoscopy contact lens of claim 1 wherein,
said aspheric surface of revolution of said contact element minimizes excess peripheral power and optical aberrations generated due to the positive refractive power of said contact element.

9. The indirect ophthalmoscopy contact lens of claim 1 wherein.

said aspheric convex surfaces of revolution of said contact element and of said anterior element are defined by the polynomial expressed as follows:
Y= (2rx + (e2-l)x2)1/2 + AxF + BxG + CxH
where r is the apical radius of curvature, e is the apical eccentricity, x is the distance from the apex of the surface along its axis of revolution, and A, B and C are constant co-efficients, and F, G and H are constant exponents wherein the values of apical radius, apical eccentricity, the co-efficients and exponents for the aspheric surfaces of said contact element and said anterior element are chosen to produce an image of the fundus of the eye free of field curvature, lateral astigmatism, and optical distortion.

10. The indirect ophthalmoscopy contact lens of claim 9 wherein,
said convex anterior surface of said contact element has an apical radius of curvature, r, in the range from 3.5mm to 9.0mm, an apical eccentricity, e, in the range from 0.05 to 1.4, coefficients A, B and C range from -10 to 10 and exponents F,G and H range from 0.5 to 10 wherein based upon the total refractive power of said contact element, these values will satisfy optical correction at the center and periphery of said contact element.

11. The indirect ophthalmoscopy contact lens of claim 9 wherein,
said concave posterior surface of said contact element is an aspheric surface of revolution defined by said polynomial and having an apical radius of curvature, r, in the range from about 6.5mm to 9.0mm, an apical eccentricity, e, in the range from 0.0 to 1.2,
coefficients A, B and C in the range from -10 to 10 and exponents F, G and H in the range from 0.5 to 10 wherein r, e, A, B, C, F, G, and H are chosen to cause said posterior surface to substantially conform to the shape of the anterior surface of the cornea of the eye to which said contact element is to be applied and to eliminate localized peripheral lens bearing during translational movement on said cornea.

12. The indirect ophthalmoscopy contact lens of claim 10 wherein,
said first and second convex surfaces of said anterior element have apical radius of curvatures, r, in the range from 5.0mm to 70.0mm, apical eccentricity, e, in the range from 0.7 to 4.0, coefficients A, B and C in the range from -10 to 10, and exponents F, G and H in the range from 0.5 to 10 wherein the generated surfaces are designed tc provide optimum fundus image forming
qualities in conjunction with said contact element having a positive refractive power as well as projecting a clear and aberration free image of a biomicroscope light source aperture on the fundus of the eye.

13. A device for observing the fundus of the eye under applied illumination comprising,
a contact lens element having a convex anterior surface and a concave posterior surface, said anterior surface being an aspheric surface of revolution,
an antericr lens element positioned relative to said contact lens element and along the same optical axis, having first and second convex surfaces being aspheric surfaces of revolu n,
a holding means supporting said contact and anterior lens elements relative to one another, wherein light rays projected from a light source are converged through the device onto the fundus of the eye and emerge from the fundus to be refracted by the device to form an image of the fundus substantially free of optical aberrations.

14. The device of claim 13 wherein,
said posterior surface of said contact lens element is an aspheric surface of revolution.

15. The device of claim 14 wherein,
said contact and anterior lens elements have positive refractive power yielding significant light converging properties and producing an extremely wide field of view of the fundus of the eye.

16. An indirect ophthalmoscopy contact lens, comprising,
a contact lens element having a convex anterior surface and a concave posterior surface,
an anterior lens element positioned relative to said contact lens element, having first and second convex surfaces being aspheric surfaces of revolution defined by the polynomial expressed as follows:
Y = (2rx + (e2-l) x ) 1 2 + AxF + BxG + CxH
where r is the apical radius of curvature, e is the apical eccentricity, x is the distance from the apex of the surface along its axis of revolution, and A, B and C are constant coefficients, and F, G and H are constant exponents wherein the values of r, e. A, B, C, E, F and G are chosen to produce an image of the fundus of the free of field curvature, lateral astigmatism, and optical aberrations, and a holding means supporting said contact and anterior lens elements relative to one another along the same optical axis.

17. The indirect ophthalmoscopy contact lens device of claim 16, wherein,
said first and second convex surfaces of said anterior element have apical radius of curvatures, r, in the range from 5.0mm to 70.0mm, apical eccentricity, e, in the range from 0.7 to 4.0, coefficients A, B and C in the range from 10, and exponents F, G and H in the range from 0.5 to 10 wherein the generated surfaces are
designed to provide optimum fundus image forming
qualities in conjunction with said contact element as well as projecting a clear and aberration free image of a biomicroscope light source aperture on the fundus of the eye.

18. The indirect ophthalmoscopy contact lens device of claim 16, wherein,
said contact element has positive refractive power and has at least its convex anterior surface being an aspheric surface of revolution, having a continuous and progressive reduction in curvature peripheralward wherein said aspheric surface of said contact element is defined by said polynomial.

19. The indirect ophthalmoscopy contact lens device of claim 18, wherein,
said convex anterior surface of said contact element has an apical radius of curvature, r, in the range from 3.5mm to 9.0mm, an apical eccentricity, e, in the range from 0.05 to 1.4, coefficients A, B and C range from -10 to 10 and exponents F, G and H range from 0.5 to 10 wherein these values are chosen to satisfy optical correction at the center and periphery of said contact element.

20. The indirect ophthalmoscopy contact lens device of claim 16, wherein,
said concave posterior surface of said contact element is an aspheric surface of revolution which has a continuous and progressive reduction in curvature
peripheralward with a peripheral slope equal to or less than that of an averaged cornea at an equivalent diameter thereby minimizing localized peripheral lens bearing during translational movement of said contact element on the cornea.