Optical Feature Rounding in Ophthalmic Lenses for Faster Subjective Testing
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Solution Overview
Problem
Existing methods for determining optical features of ophthalmic lenses for vision correction are inefficient, leading to extended examination times and potential subject impatience or fatigue, and do not account for standard lens values, resulting in inaccurate or imprecise prescriptions.
Innovation Solution
A system and method that uses an optical device and computer to perform a subjective test, adjusting test values and increments based on personal features and test results to determine a rounded optical feature value compatible with standard lens manufacturing values, reducing the number of trials and ensuring clear subject understanding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If small increments between successive trials are used to determine accurate optical feature values, then measurement precision is improved, but examination time increases and subject patience decreases
Solution Approach 1:
The system performs preliminary actions by using objective measurement data (autorefractor, retinoscopy) to establish an initial test value before the subjective trial sequence begins. This preliminary positioning allows the subjective test to start closer to the final prescription value, reducing the number of incremental trials needed and thereby shortening examination time while maintaining accuracy.
Solution Approach 2:
The system implements feedback by continuously adjusting the test value based on subject responses to each trial comparison. The computer controls the optical device to present two different optical situations and records the subject's preference, using this feedback to increment or decrement the test value systematically until the optimal value is determined, balancing precision with efficient convergence.
2Measurement precision
If small increments between successive trials are used, then measurement precision is improved, but subject understanding and clear perception of differences deteriorates
Solution Approach 1:
The system dynamically adjusts the increment size between trials based on the phase of testing. Larger increments are used when farther from the target value to maintain subject engagement and clear perception, while smaller increments are applied as the test converges toward the optimal value, ensuring both subject understanding and measurement precision throughout the process.
3Measurement precision
If standard values of optical features are not considered during testing, then measurement precision is improved, but adaptability to commercially available lenses deteriorates
Solution Approach 1:
The system performs preliminary identification of the closest standard value to the precisely determined optimal value. This preliminary action allows the system to then guide the subjective test toward this standard value, ensuring that the final prescription is both accurate and compatible with commercially available lenses without sacrificing measurement precision.
Solution Approach 2:
The system changes the target parameter from the exact optimal value to the nearest standard value available for manufacturing. This parameter change ensures adaptability to commercially available lenses while maintaining clinical accuracy, as the test is adjusted to converge on a value that can be actually implemented in lens production.
4Loss of time
If the test is shortened to maintain subject patience, then examination time is reduced, but measurement precision deteriorates
Solution Approach 1:
The system uses preliminary objective measurements to establish a starting test value close to the expected optimal value. This preliminary positioning reduces the number of trials needed to reach the final prescription, shortening examination time while maintaining measurement precision by starting the subjective test already near the target.
Solution Approach 2:
The system implements a modified trial sequence that can skip certain intermediate steps or reduce the number of trials when the subject's responses clearly indicate convergence toward the optimal value. This allows the test to be shortened when appropriate without sacrificing precision, as the systematic feedback mechanism ensures accurate determination even with fewer trials.
Data Source
AI summary
A system for determining a rounded value of an optical feature of an ophthalmic lens including determining a first test value and a first variation increment, performing a first trial of said subjective test wherein two first different optical situations are determined based on at least the first test value, determining a second test value based on the first test value, on the first variation increment and on the result of the first trial, performing a second trial of said subjective test wherein two second different optical situations are determined based on at least the second test value, determining an intermediary value based on the result of the first trial and on the result of the second trial, and determining said rounded value by rounding said intermediary value to a reference value, said rounding modifying the dioptric correction of said ophthalmic lens by less than a predetermined basic dioptric value.