Method and apparatus for measuring properties of the eye using a virtual image
First Claim
1. An apparatus for evaluating the shape of a cornea, said apparatus comprising:
- a structured light source for generating a diagnostic pattern;
an imaging system;
an optical system for projecting a virtual image of said diagnostic pattern to and at a distance in front of said cornea, and capturing a reflection of said virtual image off said cornea, and for redirecting said reflection onto said imaging system; and
processing means for determining the shape of said cornea by comparing said reflected image detected by said imaging system with stored reference information.
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Abstract
A technique for evaluating the topography of a cornea, which utilizes a virtual image of a keratoscope pattern. The topography system includes a structured light source to create the keratoscope pattern or another diagnostic pattern, an optical assembly to focus the created pattern upon the cornea, and for capturing the image reflected off the patient'"'"'s eye and directing the reflected image towards an imaging system for processing. Light emitted by the light source is preferably not in the visible range, to minimize discomfort to the patient. Since the topography is evaluated with a projected virtual image, there is no nose or brow shadow, thereby alowing better corneal coverage. The optical system includes an aperture stop which is preferably conjugate with a point behind the corneal surface approximating the center of a normal cornea. Thus, wide angle capture is achieved as reflected rays reaching the imaging system appear as if they originated at the center of the cornea. A pupil detection mechanism is disclosed which is performed independently of the diagnostic pattern illumination, thereby facilitating pupil detection. In an alternate embodiment, the diagnostic pattern is generated using a variable light pattern generator, which provides flexibility in selecting target images to achieve various diagnostic abilities. The disclosed topography system can be reconfigured to serve as a visual field measuring device, or a perimeter.
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Citations
21 Claims
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1. An apparatus for evaluating the shape of a cornea, said apparatus comprising:
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a structured light source for generating a diagnostic pattern; an imaging system; an optical system for projecting a virtual image of said diagnostic pattern to and at a distance in front of said cornea, and capturing a reflection of said virtual image off said cornea, and for redirecting said reflection onto said imaging system; and processing means for determining the shape of said cornea by comparing said reflected image detected by said imaging system with stored reference information. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A corneal measuring device including a measuring stimulus, an optical system consisting of optical elements, and an imaging device, wherein a virtual image of the measuring stimulus is projected by the optical elements to and at a distance in front of a cornea, wherein light from the virtual image of the measuring stimulus reflects off said cornea and is captured by said imaging device, and wherein the reflected light is analyzed to determine the shape of the cornea.
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15. A method for evaluating the shape of a cornea, said method comprising the steps of:
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generating a diagnostic pattern; projecting a virtual image of said diagnostic pattern to and at a distance in front of said cornea; capturing a reflection of said virtual image off said cornea; directing said reflection onto an imaging system; and determining the shape of said cornea by comparing said reflected image detected by said imaging system with stored reference information. - View Dependent Claims (16, 17, 18, 19)
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20. An apparatus for evaluating the shape of a cornea, said apparatus comprising:
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a monochromatic structured light source for generating a diagnostic pattern; an imaging system; an optical system for projecting a virtual image of said diagnostic pattern to and at a distance in front of said cornea, and capturing a reflection of said diagnostic pattern off said cornea, and for redirecting said reflection onto said imaging system; and processing means for determining the shape of said cornea by comparing said reflected pattern detected by said imaging system with stored information.
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21. An apparatus for evaluating the shape of a cornea of a patient'"'"'s eye, said apparatus comprising:
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a structured light source for generating a diagnostic pattern; an optical system for projecting a virtual image of the diagnostic pattern to and at a distance in front of said cornea, and then for capturing a reflection of said diagnostic pattern off said cornea, and redirecting said reflection onto an imaging system, said optical system including polarizing means for both polarizing the light from said structured light source and attenuating light scattering off the iris of said eye; and processing means for determining the shape of said cornea by comparing said reflected pattern detected by said imaging system with stored information.
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Specification