Optical Measurement System with Adaptive Fixation Target Brightness
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Solution Overview
Problem
Existing optical measurement systems face challenges in simultaneously drawing the eye into its farthest possible refractive state while maintaining a large pupil size, as the brightness level of the fixation target needs to be compromised between being too bright for older subjects and too dim for younger subjects, leading to inadequate measurement results.
Innovation Solution
An optical measurement system that adjusts the brightness level of the fixation target based on the subject's age category, using a camera to determine the pupil diameter and automatically setting the brightness to either 0.5 cd/m² for older subjects or 2.0 cd/m² for younger subjects to ensure accurate refractive state measurement and large pupil diameter, thereby qualifying candidates for eye surgery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the fixation target brightness is increased to ensure the eye reaches its farthest refractive state for younger subjects, then the refractive measurement accuracy is improved, but the pupil diameter decreases
Solution Approach 1:
The system dynamically adjusts the fixation target brightness level based on the subject's age category. For younger subjects (below 40 years), the brightness is set to a first level (2.0 cd/m²) to ensure the eye reaches its farthest refractive state. For older subjects (40 years and above), the brightness is set to a second level (0.5 cd/m²) to maintain adequate pupil diameter. This dynamic adjustment resolves the contradiction by adapting the brightness parameter to the specific physiological characteristics of different age groups.
Solution Approach 2:
The invention changes the brightness parameter of the fixation target based on the subject's age category. By establishing different brightness thresholds (2.0 cd/m² for younger subjects, 0.5 cd/m² for older subjects), the system optimizes the balance between achieving farthest refractive state and maintaining adequate pupil diameter for each age group, thereby resolving the measurement contradiction.
2Length of moving object
If the fixation target brightness is decreased to maintain large pupil size for older subjects, then the pupil diameter is improved, but the refractive state measurement accuracy deteriorates
Solution Approach 1:
The system dynamically adjusts the fixation target brightness level based on the subject's age category. For younger subjects (below 40 years), the brightness is set to a first level (2.0 cd/m²) to ensure the eye reaches its farthest refractive state. For older subjects (40 years and above), the brightness is set to a second level (0.5 cd/m²) to maintain adequate pupil diameter. This dynamic adjustment resolves the contradiction by adapting the brightness parameter to the specific physiological characteristics of different age groups.
Solution Approach 2:
The invention changes the brightness parameter of the fixation target based on the subject's age category. By establishing different brightness thresholds (2.0 cd/m² for younger subjects, 0.5 cd/m² for older subjects), the system optimizes the balance between achieving farthest refractive state and maintaining adequate pupil diameter for each age group, thereby resolving the measurement contradiction.
3Device complexity
If a single fixed brightness level is used for the fixation target, then the device complexity is reduced, but the adaptability to different age groups deteriorates
Solution Approach 1:
The system dynamically adjusts the fixation target brightness level based on the subject's age category. For younger subjects (below 40 years), the brightness is set to a first level (2.0 cd/m²) to ensure the eye reaches its farthest refractive state. For older subjects (40 years and above), the brightness is set to a second level (0.5 cd/m²) to maintain adequate pupil diameter. This dynamic adjustment resolves the contradiction by adapting the brightness parameter to the specific physiological characteristics of different age groups.
Solution Approach 2:
The invention changes the brightness parameter of the fixation target based on the subject's age category. By establishing different brightness thresholds (2.0 cd/m² for younger subjects, 0.5 cd/m² for older subjects), the system optimizes the balance between achieving farthest refractive state and maintaining adequate pupil diameter for each age group, thereby resolving the measurement contradiction.
Data Source
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AI summary
The invention relates to a method for measuring a characteristic of an eye of a subject, the method comprising: providing a fixation target for a subject to view; ascertaining a diameter of a pupil of the eye of the subject while the subject views the fixation target; adjusting a brightness level of the fixation target to a selected brightness level corresponding to the ascertained diameter of the pupil of the eye; and objectively measuring at least one characteristic of the eye of the subject while the subject views the fixation target at the selected brightness level.