Method and apparatus for measuring and correcting metamorphopsia
First Claim
1. An apparatus for evaluating metamorphopsia in a subject, the apparatus comprising:
- a display that displays a line pattern suitable for detecting metamorphopsia as a distortion in the line pattern;
a visual fixation target associated with the line pattern; and
an input device that selectively deforms portions of the line pattern that appear distorted to the subject, to provide a deformed pattern that neutralizes the distortion perceived by the subject.
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Accused Products
Abstract
A method and apparatus are provided for the evaluation and measurement of metamorphopsia. The apparatus includes a pattern generator that displays a deformable pattern, such as an Amsler grid, on a computer monitor. The rectilinear grid includes substantially parallel and equally spaced lines that intersect at vertices. An input device, such as a mouse, is used by a patient or technician to detect areas of the pattern where the cursor is not visible to the subject, so that areas of scotoma can be marked. The input device is also used to adjust the positions of the vertices, and distort the grid, until the grid appears substantially rectilinear to the subject. The deformations of the pattern are then recorded, and can be retrieved for comparison to subsequent test results so that changes in visual field deficits or metamorphopsia can be sensitively detected, and even corrected by a lens that distorts images in the same pattern. The present invention provides a very sensitive test for metamorphopsia that detects early retinal changes at a time when therapeutic intervention may be more helpful. The test can also be conveniently used at home, for example on a personal computer, so that the subject can be tested frequently and easily. The results of the test are mathematical maps or functions (image distortion as a function of image location) that can be used to provide therapeutic correction of metamorphopsia.
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Citations
28 Claims
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1. An apparatus for evaluating metamorphopsia in a subject, the apparatus comprising:
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a display that displays a line pattern suitable for detecting metamorphopsia as a distortion in the line pattern; a visual fixation target associated with the line pattern; and an input device that selectively deforms portions of the line pattern that appear distorted to the subject, to provide a deformed pattern that neutralizes the distortion perceived by the subject. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of evaluating metamorphopsia comprising:
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displaying a regular pattern of substantially equally spaced lines that intersect at multiple vertices, wherein the pattern is suitable for detecting metamorphopsia in a subject as a distortion in the pattern; selectively deforming the pattern to substantially neutralize the distortion perceived by the subject by moving one or more of the vertices. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method of measuring metamorphopsia in a subject, comprising:
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providing a deformable grid pattern comprising an intersecting series of orthogonal, substantially equally spaced lines that intersect at a plurality of vertices to form a grid, and a central fixation marker in the grid pattern for establishing visual fixation; moving a cursor throughout the grid pattern, while the subject maintains visual fixation on the fixation marker, and marking one or more areas of scotoma in the pattern where the cursor is not visible to the subject; deforming the grid pattern by displacing one or more of the vertices to neutralize the distortion until the deformable grid pattern appears substantially regular to the subject, whereby a deformed grid pattern is formed; and storing the deformed grid pattern and marked areas of scotoma in the pattern where the cursor is not visible to the subject.
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26. An computer system for measuring metamorphopsia in a subject, comprising:
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a pattern generator for generating a deformable grid pattern on a display screen, the pattern having a fixation target and substantially equally spaced, orthogonal lines that intersect at a plurality of vertices; a cursor that is movable throughout the pattern; an input device that marks areas of the pattern where the cursor is not visible to the subject, and displaces one or more vertices of the intersecting lines from an original vertex position, in response to input from the subject, thereby forming a deformed grid pattern which neutralizes the metamorphopsia seen by the subject; and a memory device that stores the areas of the pattern where the cursor is not visible to the subject, and records displacements of the vertices from the original position. - View Dependent Claims (27, 28)
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Specification