IOL-Specific Wavefront Measurement for Reliable Dioptric Power
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Solution Overview
Problem
Conventional methods for calculating dioptric power in eyes with implanted intraocular lenses (IOLs) lack reliability due to the uniform approach, which does not account for the specific type of IOL, leading to inconsistent and less accurate results.
Innovation Solution
An ophthalmic apparatus that measures wavefront aberration using a Hartmann image and adjusts its measurement method based on the type of IOL, including monofocal, multifocal refractive, multifocal diffractive, and extended depth of focus types, by determining the focal point distance and calculating dioptric power using Zernike polynomial approximation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a uniform method is used to calculate dioptric power for all eyes with IOLs, then the measurement process is simple and consistent, but the reliability and accuracy of the dioptric power calculation deteriorates due to not accounting for specific IOL types
Solution Approach 1:
The measurement system dynamically adapts its calculation method based on the detected IOL type. The controller automatically selects different arithmetic processing methods (e.g., different Zernike polynomial approximation approaches) depending on whether the IOL is monofocal, multifocal refractive, multifocal diffractive, or extended depth of focus, making the system flexible and adaptive rather than static and uniform
Solution Approach 2:
The system changes the calculation parameters and arithmetic processing methods based on the IOL type. By detecting which type of IOL is implanted, the system modifies the dioptric power calculation parameters to match the specific optical characteristics of that IOL type, thereby improving measurement accuracy without requiring manual intervention
2Measurement precision
If the measurement method is tailored to specific IOL types, then the accuracy of dioptric power determination is improved, but the complexity of the measurement system increases due to multiple measurement approaches
Solution Approach 1:
The system performs preliminary detection of the IOL type before executing the dioptric power measurement. By identifying the IOL type in advance (through transillumination imaging or database comparison), the system can pre-select the appropriate calculation method, ensuring measurement accuracy while automating the complexity management rather than requiring real-time complex decision-making during measurement
Solution Approach 2:
The system incorporates feedback mechanisms where the detected IOL type information feeds back into the measurement process to automatically adjust the calculation method. This closed-loop approach ensures that the most appropriate arithmetic processing method is selected based on the actual IOL characteristics, improving precision while maintaining systematic control over the increased complexity
3Reliability
If a single arithmetic processing method is used for all IOL types, then the calculation process is efficient and quick, but the consistency and reliability of results deteriorates across different IOL types
Solution Approach 1:
The calculation process dynamically adjusts its arithmetic processing method based on the IOL type detection results. Rather than using a static single method for all cases, the system automatically transitions between different calculation approaches (such as varying Zernike polynomial orders or approximation techniques) to match the specific optical properties of each IOL type, ensuring consistent and reliable results across diverse lens types
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Improves the reliability of dioptric power calculation by tailoring the measurement method to the specific type of IOL, resulting in more accurate and precise dioptric power determination for eyes with implanted lenses.
Implementation Method 1
measure wavefront aberration of an eye to be examined wearing an intraocular lens to acquire a Hartmann image
Implementation Method 2
measurement optical system including a focusing lens
Data Source
AI summary
An ophthalmic apparatus includes a measurement optical system, an acquisition unit, a controller, and a calculator. The measurement optical system includes a focusing lens, and is configured to measure wavefront aberration of an eye to be examined wearing an intraocular lens to acquire a Hartmann image. The acquisition unit is configured to acquire intraocular lens information representing at least an optical characteristics of the intraocular lens. The controller is configured to move the focusing lens to a position corresponding to a focal point distance of the intraocular lens determined based on the intraocular lens information and to cause the measurement optical system to acquire the Hartmann image. The calculator is configured to calculate a dioptric power of the eye to be examined based on the Hartmann image using an arithmetic processing method corresponding to the intraocular lens information.