US4439025A — Variable circular dual image corneal radius measu…

Claim 1

Independent Claim 130 words

An instrument for measuring the radius of curvature of a cornea of an eye comprising: a housing; means mounted within said housing for projecting a reference image on the cornea along an axis perpendicular to said cornea, said reference image comprising substantially a circle having a diameter; a rod of refractile transparent material disposed within said housing and mounted along said axis for optically forming two images substantially identical to said reference image; means for varying the diameter of said reference image and said two images substantially identical to said reference image, such that said images form a predetermined image pattern; and means for measuring the diameter of said reference image when said predetermined image pattern is formed to provide an indication of the radius of curvature of the cornea.

Claim 2

Dependent Claim 130 words

An instrument for measuring the radius of curvature of a cornea of an eye comprising: a housing; means mounted within said housing for projecting a reference image on the cornea along an axis perpendicular to said cornea, said reference image comprising substantially a circle having a diameter; a rod of refractile transparent material disposed within said housing and mounted along said axis for optically forming two images substantially identical to said reference image; means for varying the diameter of said reference image and said two images substantially identical to said reference image, such that said images form a predetermined image pattern; and means for measuring the diameter of said reference image when said predetermined image pattern is formed to provide an indication of the radius of curvature of the cornea.

Claim 3

Dependent Claim 18 words

The instrument of claim 1 wherein said circle is composed of a plurality of discontinuous dots of light.

Claim 4

Dependent Claim 96 words

The instrument of claim 1 wherein said means for projecting a reference image on the cornea includes: a first plate being generally opaque and having a plurality of linear radial non-opaque segments disposed thereon; a second plate being generally opaque and having a plurality of curvilinear radial non-opaque segments disposed thereon; and said first and second plates being disposed adjacent one another, such that portions of said plurality of linear radial non-opaque segments and portions of said plurality of curvilinear radial non-opaque segments overlap, said overlapping portions thereby forming substantially a circle of discontinuous non-opaque segments.

Claim 5

Dependent Claim 52 words

The instrument of claim 3 wherein said means for varying the diameter of said reference image includes: means for rotating said second plate with respect to said first plate, such that said overlapping portions of non-opaque segments of said first and second plates are radially displaced as said second plate is rotated.

Claim 6

Dependent Claim 36 words

The instrument of claim 1 and further including: means for rotating said rod of refractile transparent material to thereby rotate said images to measure the radius of curvature along a plurality of meridians of the cornea.

Claim 7

Dependent Claim 163 words

In an optical instrument employing a microscope adapted to bring into focus the cornea of a patient's eye to provide a reference distance in connection with the measurement of the radius of curvature of the cornea, the combination which comprises: means for projecting a reference image on the cornea of the eye disposed in a plane perpendicular to the optical axis of the eye and of the microscope; a rod of refractile transparent material mounted in the field of view of the microscope with a diagonal of the cross-section thereof common to the optical axis of the microscope for optically forming two images substantially identical to said reference image as viewed through said rod; means for varying the size of said images, such that said images form a predetermined image pattern; and means for measuring the diameter of said reference image when said predetermined image pattern is formed to provide an indication of the radius of curvature of the cornea of the eye.

Claim 8

Dependent Claim 163 words

In an optical instrument employing a microscope adapted to bring into focus the cornea of a patient's eye to provide a reference distance in connection with the measurement of the radius of curvature of the cornea, the combination which comprises: means for projecting a reference image on the cornea of the eye disposed in a plane perpendicular to the optical axis of the eye and of the microscope; a rod of refractile transparent material mounted in the field of view of the microscope with a diagonal of the cross-section thereof common to the optical axis of the microscope for optically forming two images substantially identical to said reference image as viewed through said rod; means for varying the size of said images, such that said images form a predetermined image pattern; and means for measuring the diameter of said reference image when said predetermined image pattern is formed to provide an indication of the radius of curvature of the cornea of the eye.

Claim 9

Dependent Claim 30 words

The combination of claim 6 wherein said means for projecting a reference image comprises means for generating a substantially circular image having a diameter and being composed of discontinuous dots.

Claim 10

Dependent Claim 26 words

The combination of claim 7 wherein said means for varying the size of said images includes means for varying the diameter of said substantially circular image.

Claim 11

Dependent Claim 97 words

The combination of claim 8 wherein said means for generating said substantially circular image includes: a light source; a first plate being generally opaque and having a plurality of linear radial non-opaque segments disposed thereon; a second plate disposed adjacent said light source and being generally opaque and having a plurality of curvilinear radial non-opaque segments disposed thereon; said first and second plates being disposed adjacent one another, such that portions of the opaque area occlude the passage of light from said light source to the cornea, the unoccluded portions projecting said discontinuous dots onto the cornea.

Claim 12

Dependent Claim 59 words

The combination of claim 9 wherein said means for varying the diameter of said substantially circular image includes: means for rotating said second plate with respect to said first plate, such that said unoccluded portions of said non-opaque segments of said first and said second plates are radially displaced relative to each other as said second plate is rotated.

Claim 13

Dependent Claim 29 words

The combination of claim 9 wherein said light source comprises: a circular ring lying in a plane perpendicular to the optical axis of the eye and of the microscope.

Claim 14

Dependent Claim 27 words

The combination of claim 6 and further including: means for moving said rod of refractile material into and out of the field of view of the microscope.

Claim 15

Dependent Claim 13 words

The combination of claim 6 wherein said rod is square in cross-sectional shape.

Claim 16

Dependent Claim 124 words

A Keratometer comprising: a housing; means mounted within said housing for projecting a reference circle having a diameter and comprising discontinuous dots of light onto a cornea for reflection of a generally circular image from the cornea along an axis perpendicular to said cornea; a rod of refractile transparent material disposed within said housing and mounted along said axis for receiving said reflection from said cornea to optically form two image circles substantially identical to said reference circle of discontinuous dots when viewed through said rod; means for varying the diameter of said circles, such that said reference circle is disposed tangent to said image circles along a line; and means for measuring the diameter of said circles when aligned tangent to one another.

Claim 17

Dependent Claim 124 words

A Keratometer comprising: a housing; means mounted within said housing for projecting a reference circle having a diameter and comprising discontinuous dots of light onto a cornea for reflection of a generally circular image from the cornea along an axis perpendicular to said cornea; a rod of refractile transparent material disposed within said housing and mounted along said axis for receiving said reflection from said cornea to optically form two image circles substantially identical to said reference circle of discontinuous dots when viewed through said rod; means for varying the diameter of said circles, such that said reference circle is disposed tangent to said image circles along a line; and means for measuring the diameter of said circles when aligned tangent to one another.

Claim 18

Dependent Claim 101 words

The Keratometer of claim 14 wherein said means mounted within said housing for projecting a reference circle includes: a light source; a first plate being generally opaque and having a plurality of linear radial non-opaque segments disposed thereon; a second plate disposed adjacent said light source and being generally opaque and having a plurality of curvilinear radial non-opaque segments disposed thereon; and said first and second plates being disposed adjacent one another, such that portions of the opaque area occlude the passage of light from said light source to the cornea, the unoccluded portions projecting said discontinuous dots onto the cornea.

Claim 19

Dependent Claim 52 words

The Keratometer of claim 15 wherein said means for varying the diameter of said circles includes: means for rotating said second plate with respect to said first plate, such that said unoccluded portions of said non-opaque segments of said first and second plates are radially displaced as said second plate is rotated.

Claim 20

Independent Claim 135 words

A method for the measurement of the curvature of the cornea of an eye comprising the steps of: establishing an object pattern comprising a reference circle having a diameter and being composed of discontinuous dots positioned for reflection from the cornea; projecting the reference circle onto the surface of the cornea; viewing the reflection of the reference circle through a refractile transparent rod at a reference position where a medial diagonal of the rod is located at the line of sight of the pattern to thereby optically form two images of the reference circle viewed through the rod; varying the diameter of the reference circle and the diameter of the image circles, such that the image circles lie tangent to the reference circle; and measuring the diameter of the reference circle in the tangent position.

Claim 21

Independent Claim 135 words

A method for the measurement of the curvature of the cornea of an eye comprising the steps of: establishing an object pattern comprising a reference circle having a diameter and being composed of discontinuous dots positioned for reflection from the cornea; projecting the reference circle onto the surface of the cornea; viewing the reflection of the reference circle through a refractile transparent rod at a reference position where a medial diagonal of the rod is located at the line of sight of the pattern to thereby optically form two images of the reference circle viewed through the rod; varying the diameter of the reference circle and the diameter of the image circles, such that the image circles lie tangent to the reference circle; and measuring the diameter of the reference circle in the tangent position.

Claim 22

Dependent Claim 45 words

The method of claim 17 wherein the step of establishing an object pattern includes: projecting a light source through a first opaque plate having a plurality of linear radial non-opaque segments and a second substantially opaque plate having a plurality of curvilinear radial non-opaque segments.

Claim 23

Dependent Claim 21 words

The method of claim 18 wherein the step of varying the diameter of the reference circle includes rotating the second plate.

Claim 24

Dependent Claim 27 words

The method of claim 17 and further including the step of rotating the rod for measuring the curvature of the cornea at varying meridians of the eye.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1987-03-27	1987-09-26	1988-03-27	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1991-03-27	1991-09-26	1992-03-27	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1995-03-27	1995-09-26	1996-03-27	$7700.00	Window Closed / Lapsed

Variable circular dual image corneal radius measurement instrument

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