Single Lens Subjective Refraction via Orthogonal Power Variation
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Solution Overview
Problem
Existing methods for subjective refraction, such as those using phoropters, are bulky and require trained experts, limiting accessibility, especially in areas without ready access to such equipment.
Innovation Solution
A single lens with varying mean power in one direction and cylindrical power in an orthogonal direction, allowing for subjective refraction by semi-skilled individuals or self-refraction, using a hand-held optical element with zones and axis orientations to identify the correct prescription.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a phoropter is used for subjective refraction, then measurement precision is improved, but device complexity and portability worsen
Solution Approach 1:
The patent extracts only the essential functional elements from the complex phoropter system. Instead of using a complete phoropter with multiple lens arrays and adjustment mechanisms, the invention uses a single lens element that integrates the core refraction testing capability, thereby simplifying the device while maintaining measurement precision for subjective refraction
Solution Approach 2:
The single lens element is designed to perform multiple functions that were previously distributed across separate phoropter components. It provides both spherical and cylindrical power adjustments, enables subjective refraction testing, and can be used with various target charts, making the simplified device universally capable of performing refraction measurements
2Measurement precision
If a phoropter is used for subjective refraction, then measurement precision is improved, but ease of operation worsens
Solution Approach 1:
The patent removes the complex adjustment mechanisms and training requirements associated with phoropters. The simplified single-lens design eliminates the need for trained experts to operate the device, allowing semi-skilled individuals to perform subjective refraction with ease while maintaining accurate measurements
Solution Approach 2:
The device is designed to be self-contained and easy to use without requiring specialized training. The single lens element with its integrated power ranges allows users to independently perform refraction testing by simply presenting the lens to the patient's eye and observing through the lens, making the operation as simple as holding up a single optical element
3Measurement precision
If a phoropter is used for subjective refraction, then measurement precision is improved, but portability worsens
Solution Approach 1:
The patent extracts only the essential optical element from the bulky phoropter system. By using a single lens element instead of a complete phoropter apparatus, the invention dramatically reduces the weight and size of the device, making it highly portable while preserving the ability to perform accurate subjective refraction measurements
Solution Approach 2:
The invention transitions from a three-dimensional complex phoropter structure to a two-dimensional single-lens element. This dimensional simplification reduces the device's physical footprint and weight, enabling portability in remote areas while maintaining full refraction testing capability through the optimized optical design of the single lens
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
Enables lightweight, inexpensive, and portable subjective refraction, facilitating access in areas lacking phoropters, allowing for accurate prescription determination without the need for trained professionals.
Implementation Method 1
A spherical correction (referred to also simply as 'sphere') corrects refractive error of the eye with a single convergent or divergent refractive power in all meridians. A cylindrical power ('cyl') corrects astigmatic refractive error of the eye by adding or subtracting power cylindrically in a meridian specified by the prescribed axis.
Data Source
Figure 1A~1B
Figure 2~3B
Figure 4A~4B
AI summary
An article for performing a subjective refraction includes a lens having a mean power that varies across the lens in a first direction and a cylindrical power that varies across the lens in a second direction, orthogonal to the first direction, wherein the mean power varies by four diopters or more and the cylindrical power varies by four diopters or more.