# US 2019/0167091 A1 · Measuring visual acuity of a client > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0167091 A1 - Document ID: US20190167091A1 - Status: Published application - Kind: A1 - Application number: 16/321,293 - Filed: 2016-07-29 - Published: 2019-06-06 - Earliest claimed: 2016-07-29 - Assignees: Medicontur Medical Engineering Ltd. - Applicants: Medicontur Medical Engineering Ltd. - Inventors: Gabor ERDEI; Csilla FULEP - Web page: https://patentgrep.com/patent/US20190167091A1 ## CPC - A61B 3/0025: {characterised by electronic signal processing, e.g. eye models} - A61B 3/0058: {for multiple images} - A61B 3/032: Devices for presenting test symbols or characters, e.g. test chart projectors (A61B3/036 takes precedence) - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract In clinical visual acuity measurements a method a system and a device for measuring visual acuity of a client is provided. 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. ## Claims ### Claim at position 1 1: A method for measuring visual acuity of a client, said method comprising the steps of on a display device (41), displaying (S411) sets of symbols in different size to the client, in an input device (42), receiving (S421) responses of the client indicative to the identity of the symbols, in a computing device (43), a) registering (S431) values to the responses belonging to pre-calculated values of similarity of the symbols, which pre-calculated values of similarities are correlation values calculated for pairs of symbols of a given symbol size, b) calculating (S432) a value of rate of recognition, RR, for each symbol size, each being an average of the registered values for a given symbol size, c) determining (S433) the measured visual acuity from the RR values. ### Claim at position 2 (depends on 1) 2: The method of claim 1, in which the symbols are characters, letters or optotypes of different size. ### Claim at position 3 (depends on 1) 3: The method of claim 1, in which responses are voice or tactile reactions about the identity of the symbols entered to the input device (42). ### Claim at position 4 (depends on 1) 4: The method of claim 1, in which the pre-calculated values of similarities are correlation values calculated for pairs of symbols. ### Claim at position 5 (depends on 4) 5: The method of claim 4, in which correlation values are optotype correlations, OC, and calculated by OC ≡ ρ - ρ _ 1 - ρ _ , where, ρ is the Pearson's correlation distribution of all symbols, and ρ indicates the expected value of the Pearson's correlation distribution without the unity values. ### Claim at position 6 (depends on 1) 6: The method of claim 1, in which RR is calculated as the average of the registered values for each symbol size. ### Claim at position 7 (depends on 1) 7: The method of claim 1, in which determining the measured visual acuity from the RR values comprises calculating a function fitting to the RR values of each symbol size and defining visual acuity belonging to a RR threshold, RR0. ### Claim at position 8 (depends on 7) 8: The method of claim 7, in which the function fitting to the RR values is a Super-Gaussian (SG) function. ### Claim at position 9 9: A system for measuring visual acuity of a client, comprising a display device (41), an input device (42) and a computing device (43), wherein 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 values to the responses belonging to pre-calculated values of similarity of the symbols, b) calculating a value of rate of recognition, RR, for each symbol size, and c) determining the measured visual acuity from the RR values. ### Claim at position 10 (depends on 9) 10: The system of claim 9, in which the computing device (43) is capable of controlling the display device for generating the images of the symbols. ### Claim at position 11 (depends on 9) 11: The system of claim 9, in which the display device (41) is a screen displaying the images of symbols projected by a projector. ### Claim at position 12 (depends on 9) 12: The system of claim 9, in which the display device (41) is a monitor that is comprised in or connected to the computing device. ### Claim at position 13 (depends on 9) 13: The system of claim 9, in which the input device (42) includes a voice recognition module (421) or a tactile reaction recognition module (422) that are operative to receive responses of the client indicative to the identity of the symbols. ### Claim at position 14 14: A computing device (43) receiving information from an input device (42) for computing visual acuity of a client, said computing device (43) comprising a processor (431) and a storage (432), said storage (432) containing instructions executable by said processor (431) whereby said computing device (43) is operative to a) register values to the responses belonging to pre-calculated values of similarity of the symbols, b) calculate a value of rate of recognition, RR, for each symbol size, c) determine the measured visual acuity from the RR values. ### Claim at position 15 (depends on 14) 15: The computing device (43) of claim 14, in which the computing device (43) is operative to calculate RR as the average of the registered values for each symbol size. ### Claim at position 16 (depends on 14) 16: The computing device (43) of claim 14, in which the computing device (43) is operative to determine the measured visual acuity from the RR values comprises by calculating a function fitting to the RR values of each symbol size and defining visual acuity belonging to a RR threshold, RR0. ### Claim at position 17 (depends on 1) 17: A computer program comprising instructions which, when executed by at least one processor of a computing device, causes the computing device to carry out the method of claim 1. ### Claim at position 18 (depends on 16) 18: A storage (432) containing the computer program of claim 16, comprising at least a registration part (4321), a calculation part (4322) and a determination part (4323).