Statistical Autorefractor Using Empirical Scaling for Subjective Refraction
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Solution Overview
Problem
Conventional methods for determining a refractive prescription using wavefront sensors often result in discrepancies between autorefraction and subjective refraction measurements, leading to inefficiencies in optometrist workflows, as they do not accurately correlate with final subjective refraction results.
Innovation Solution
The method involves using wavefront sensor measurements to determine Zernike coefficients, which are then scaled based on predetermined data from a large set of eyes to provide a starting prescription for subjective refraction, thereby improving correlation with subjective refraction results by adjusting scaling coefficients to minimize differences between estimated and subjectively determined corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If model-based techniques are used to calculate Rx from wavefront errors, then the calculation process is automated and objective, but the calculated Rx does not correlate well with subjective refraction results
Solution Approach 1:
The patent transforms the Rx calculation by changing the parameters used: instead of relying solely on theoretical optical models, it uses empirically-derived scaling factors applied to Zernike coefficients that have been optimized to match subjective refraction outcomes. This parameter transformation bridges the gap between objective measurement and subjective perception.
Solution Approach 2:
The patent incorporates feedback by using a large dataset of paired objective measurements and subjective refraction results to derive scaling relationships. This feedback loop allows the system to learn from actual clinical outcomes and adjust the calculation parameters accordingly, improving correlation with subjective results.
2Device complexity
If conventional model-based wavefront calculations are used, then the method is simple and direct, but the results show significant variations from subjective refraction
Solution Approach 1:
The patent introduces an intermediary layer between the raw wavefront measurements and the final Rx calculation. This intermediary consists of empirically-determined scaling factors that mediate the relationship between objective measurements and subjective outcomes, improving reliability without significantly complicating the overall process.
3Measurement precision
If scaling coefficients are adjusted to match subjective refraction data, then correlation with subjective results improves, but the method requires large datasets and complex optimization
Solution Approach 1:
The patent performs preliminary action by pre-calculating the optimal scaling factors using a large dataset before actual clinical use. This preprocessing step creates a lookup table or stored optimization results that can be quickly applied during routine examinations, reducing the computational burden during actual use while maintaining high correlation with subjective refraction.
Data Source
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AI summary
Methods for determining a prescription (Rx) for a person include providing aberrometric data characterizing wavefront errors of the persons eye, the aberrometric data being obtained using an wavefront sensor and comprising one or more coefficients characterizing the wavefront errors; determining a starting Rx for the persons eye based on the one or more coefficients and on predetermined information relating aberrometric data and subjective refraction data for a plurality of peoples eyes; and reporting the starting Rx to an eye care professional.