Astigmatic Optotype Alignment for Faster Visual Acuity Testing
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Solution Overview
Problem
Existing methods for determining visual acuity in individuals with astigmatic visual defects are lengthy, time-consuming, and prone to errors due to the need for active feedback and cumbersome optical cylinder corrections, which often prevent accurate acuity assessment, especially in cases of significant cylinder defects.
Innovation Solution
A method that determines visual acuity by selecting a preferential direction aligned with the cylinder axis or rotated by 90°, applying optical spherical corrections, and using adapted visual signs with directional features parallel to this direction to assess acuity without requiring optical cylinder corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical cylinder correction is applied to compensate for astigmatic visual defect, then visual acuity can be accurately determined, but the process becomes lengthy, time-consuming and cumbersome
Solution Approach 1:
The patent extracts and removes the optical cylinder correction component from the visual acuity determination process. Instead of using traditional cylinder lenses to compensate for astigmatism, the method uses specially designed astigmatic optotypes that inherently account for the astigmatic defect, eliminating the need for time-consuming cylinder correction trials while maintaining measurement accuracy
Solution Approach 2:
The patent applies preliminary action by pre-calculating and pre-configuring the astigmatic optotypes based on the subject's known astigmatic parameters (cylinder power and axis) before the visual acuity test begins. This allows the test to proceed directly with appropriately adapted visual signs without requiring real-time optical corrections during the examination
2Measurement precision
If optical cylinder correction is held up in front of trial frame or phoropter, then astigmatic visual defect can be compensated, but device combination becomes cumbersome and requires additional space
Solution Approach 1:
The patent removes the external optical cylinder correction apparatus from the device combination. By encoding astigmatic compensation directly into the visual signs themselves, the system eliminates the need for separate cylinder lenses, trial frames, or phoropters, thereby simplifying the overall device configuration and reducing spatial requirements
Solution Approach 2:
The patent merges the astigmatic correction function with the visual acuity test target. The astigmatic optotypes combine the functions of both the test stimulus and the correction mechanism into a single integrated element, eliminating the need for multiple separate devices and their complex combinations
3Measurement precision
If active feedback from test person is used for visual acuity determination, then acuity can be measured, but the process becomes error-prone and time-consuming
Solution Approach 1:
The patent implements self-service by designing the astigmatic optotypes to automatically adapt to the subject's astigmatic condition without requiring active participation in correction trials. The visual signs self-adjust based on pre-input astigmatic parameters, reducing the subject's role to simple observation and response, thereby minimizing human error and increasing measurement reliability
Data Source
AI summary
A method for determining acuity-of-vision characteristics of a test person with a astigmatic visual defect, including: providing visual defect data for the test person, wherein the visual defect data includes a cylinder axis or axial position of a required optical cylinder correction; selecting a preferential direction such that this preferential direction either corresponds to the cylinder axis which is assigned to the optical cylinder correction, is rotated by 90° to this cylinder axis, or is derived from wavefront data using a point spread function; applying an optical power in the selected preferential direction; displaying an adapted visual sign, which has a directional feature, wherein the adapted visual sign is displayed aligned such that its directional feature is parallel to the preferential direction; and determining acuity-of-vision characteristics of the test person for the selected preferential direction, taking into account a dimension of the directional feature and the applied optical power.