Measuring visual acuity of a client

A technology of user vision and acuity, which is applied in the direction of eye testing equipment, applications, medical science, etc., can solve problems such as not considering the similarity of different symbols, and achieve the effect of reducing uncertainty

Active Publication Date: 2019-05-03
MEDICONTUR MEDICAL ENG
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The problem with this related technique is that it also does not take into account the similarity of different symbols

Method used

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  • Measuring visual acuity of a client
  • Measuring visual acuity of a client
  • Measuring visual acuity of a client

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Experimental program
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Embodiment Construction

[0026] Similarity quantification between symbols can be performed on the basis of correlation calculations. This measure is called "optotype correlation" (OC). The term "optotype" represents symbols, characters or numbers in the prior art. The OC must not depend on how the user views the symbol; rather, it should compare the symbol in its original form to avoid user-specific artefacts. Also, the OC value is not affected by the size of the symbol, only the shape of the symbol should be considered in its definition. For this purpose, a precomputation of OC is performed on an undistorted, high-resolution, black-and-white image of a symbol (eg, on an image of capital letters of the English alphabet, where the image is represented as a two-dimensional matrix). A mathematical function developed specifically for image comparison is called Pearson correlation, which characterizes the similarity of two images by a single scalar value ρ(p,q) according to the following formula:

[002...

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Abstract

The invention provides a method, a system and a device for measuring visual acuity of a client in clinical visual acuity measurements. In accordance with the implementation, the system comprises a display device (41), an input device (42) and a computing device (43). The display device (41) is capable of displaying sets of symbols in different size to the client. The input device (42) is capable of receiving responses of the client indicative to the identity of the symbols, and the computing device (43) is capable of a) registering (S431) values to the responses belonging to pre-calculated values of similarity of the symbols, b) calculating (S432) a rate of recognition value for each symbol size, and c) determining (S433) the measured visual acuity from the rate of recognition values.

Description

technical field [0001] The present invention generally relates to clinical visual acuity measurement. In particular, but not by way of limitation, the invention is directed to a method, system and apparatus for improving the measurement of visual acuity of a user. Background technique [0002] Visual acuity is the most important ophthalmic quantity describing the perceptual resolution ability of the human eye. Its measurement is based on symbol (letters, numbers or any type of character) recognition. However, recognition depends not only on the optical properties of the eye, but also on cognitive and motor abilities. Due to this complexity, visual acuity values ​​are influenced by mental state, fatigue, and environmental factors. In clinical practice, visual acuity charts or eye charts are used to perform routine measurements. The task of the user is to correctly recognize the symbol, whose size decreases line by line. According to the "line assignment" scoring method, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): A61B3/032A61B3/00
CPCA61B3/032A61B3/0025A61B3/0058
Inventor G.埃戴C.富莱普
Owner MEDICONTUR MEDICAL ENG
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