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Method for acquiring human corneal topography

A cornea and topography technology, used in eye testing equipment, medical science, diagnosis, etc., to solve problems such as sensitivity and resolution limitations

Active Publication Date: 2020-04-10
SICHUAN UNIV
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Problems solved by technology

This method can increase sensitivity by reducing the spatial period of the grating or increasing the projection angle of the grating, but like the Moiré deflection method, sensitivity and resolution may be limited by diffraction effects

Method used

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  • Method for acquiring human corneal topography
  • Method for acquiring human corneal topography
  • Method for acquiring human corneal topography

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Embodiment Construction

[0040] The present invention will be described in more detail below in conjunction with the accompanying drawings and specific embodiments. It is necessary to point out that the following examples are only used for further description of the present invention, and cannot be interpreted as limiting the protection scope of the present invention, and those skilled in the art make some non-essential improvements to the present invention according to the above-mentioned content of the present invention And adjustments still belong to the protection scope of the present invention.

[0041] attached figure 1 A group of concentric rings are displayed on the middle LCD display. The center of the concentric rings on the display is on the same optical axis as the camera pinhole and the cornea apex, and the display and the cornea are perpendicular to the platform and parallel to each other. attached figure 2 Shown is the principle diagram of the present invention, point O is the cornea...

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Abstract

The invention provides a method for acquiring human corneal topography by using a trigonometric function, recursion and other mathematical methods. According to the method, concentric rings need to bedisplayed by an LCD display device, a cornea performs reflection and a camera performs receiving; and the x, y coordinates Xs, Ys of pixels on the LCD display device, the x, y coordinates Xc, Yc of the CCD, the x, y coordinates Xm, Ym of the human cornea as well as a distance from the midpoint of the display device and the pinhole of the camera to the vertex of the human cornea are known. According to a geometrical relationship of all the elements and assumption of forming of the cornea by a plurality of adjacent arcs, a curvature radius and a z coordinate of a first circular ring are obtained and then recursion is conducted in sequence to calculate the curvature radius and the z coordinate of the whole cornea, so that the terrain of the human cornea is obtained. According to the method,the accuracy of the human corneal topography is improved.

Description

technical field [0001] The invention relates to a method of assuming that the cornea is composed of many arcs, using trigonometric functions, recursion and other mathematical methods to obtain the equivalent value of the radius of curvature of the cornea, thereby obtaining the topography of the human cornea. Background technique [0002] Corneal topography can intuitively see the surface shape, radius of curvature, and diopter of the human cornea. Through this information, doctors can accurately and quickly judge the patient's condition and treat it. At present, the more popular detection methods in the world: Placido disk measurement method, interferometry method, Moiré deflection measurement method, grating stereo imaging measurement method, projected Moiré fringe measurement method, Fourier transform profilometry, and the use of slit lamp measurement . Most of the current medical corneal topographs use the Placido disc method. [0003] The following three techniques, pl...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): A61B3/107
CPCA61B3/107
Inventor 李大海刘肖萧张新伟刘春玲赖恒洪铁鑫黄永志邓欢
Owner SICHUAN UNIV
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