Refractive Assessment Tool Using Lenslet Array and Digital Pre-warping
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Solution Overview
Problem
There is a need for a low-cost, accurate tool to assess refractive disorders, particularly in developing countries where optometrists are scarce and patients cannot afford them, to determine spherical power, cylindrical power, and cylindrical axis for corrective eyeglass prescriptions.
Innovation Solution
A process and apparatus using an electronic visual display with an array of lenslets or pinholes to display patterns that allow users to align images, determining refractive parameters by controlling the display to change patterns based on user input, and using interactive software to measure refractive errors without physically moving optical elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional refraction assessment methods are used, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex mechanical optical systems with a computational approach using a camera, display screen, and processor. Instead of using sophisticated optical benches and manual measurement devices, the system uses digital image processing and coordinate transformation algorithms to assess refractive parameters, thereby reducing mechanical complexity while maintaining measurement capability
Solution Approach 2:
The patent creates a virtual copy of the optical measurement process through software simulation. By mapping real-world coordinates to image coordinates through mathematical transformations, the system replicates the function of complex optical measurement equipment using computational models, reducing the need for expensive physical optical components
2Measurement precision
If sophisticated optical equipment is used, then measurement precision is improved, but ease of operation deteriorates
Solution Approach 1:
The patent enables the system to automatically perform measurements and calculations without requiring skilled operators. The processor automatically captures images, performs coordinate transformations, calculates refractive parameters, and generates results, making the system self-sufficient and easy to operate for users without specialized training in optometry
Solution Approach 2:
The patent creates a multi-functional device that can assess various refractive parameters (sphere, cylinder, axis) using a single integrated system. The same camera-display-processor combination handles multiple measurement tasks, replacing the need for multiple specialized instruments and making the system accessible to a broader range of users
3Measurement precision
If traditional diagnostic tools are used, then measurement precision is improved, but cost increases
Solution Approach 1:
The patent uses inexpensive, readily available consumer electronics components (camera, display screen, processor) instead of expensive specialized optical equipment. These standard components can be manufactured at low cost and integrated into affordable diagnostic devices, making precise refraction assessment accessible in resource-limited settings
Solution Approach 2:
The patent changes the fundamental approach from optical parameter measurement to digital image coordinate analysis. By transforming the measurement domain from physical optics to digital image processing, the system achieves comparable precision using much cheaper computational methods rather than expensive optical hardware
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
This method provides an affordable and accurate means to assess refractive disorders, including myopia, hyperopia, and astigmatism, by aligning patterns to determine refractive parameters, improving accessibility in resource-limited areas and reducing the need for expensive diagnostic equipment.
Implementation Method 1
an array of lenslets or pinholes, positioned so that light from the electronic visual display passes through the array and reaches the optical system
Data Source
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AI summary
In exemplary implementations, this invention is a tool for subjective assessment of the visual acuity of a human eye. A microlens or pinhole array is placed over a high- resolution display. The eye is brought very near to the device. Patterns are displayed on the screen under some of the lenslets or pinholes. Using interactive software, a user causes the patterns that the eye sees to appear to be aligned. The software allows the user to move the apparent position of the patterns. This apparent motion is achieved by pre- warping the position and angle of the ray-bundles exiting the lenslet display. As the user aligns the apparent position of the patterns, the amount of pre-warping varies. The amount of pre-warping required in order for the user to see what appears to be a single, aligned pattern indicates the lens aberration of the eye.