Vision Testing With Retinal Fixation and Wavefront Error Correction
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Solution Overview
Problem
Existing visual acuity tests, such as those using printed and electronic charts, are inaccurate for evaluating retinal status due to optical factors like stray light, pupil size variation, and lack of fixation control, which can lead to variability and inaccuracy in measuring visual function, particularly in conditions affecting the aging eye.
Innovation Solution
The use of video rate near infrared retinal imaging to pinpoint fixation location and assess fixation stability, combined with wavefront sensor measurements to correct optical errors beyond sphere and cylinder, and a system that projects visual targets through a fixed pupil size to minimize light scatter and aberrations, along with a novel statistical analysis to quantify potential vision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If printed and electronic charts are used to measure visual acuity, then the tests are standardized, easy to use, and can be widely distributed, but they are inaccurate for evaluating retinal status due to optical factors like stray light, poor transmission, and lack of sharp focus
Solution Approach 1:
The patent introduces an optical system with a light source, condenser lens, and retinal illuminator as an intermediary between the visual acuity chart and the retina. This intermediary system controls illumination parameters (intensity, distribution, wavelength) to optimize retinal imaging quality while maintaining chart-based testing simplicity, thereby resolving the contradiction between ease of use and measurement accuracy
Solution Approach 2:
The patent changes physical parameters of the illumination system including light intensity, spectral composition, and spatial distribution of light on the retina. By optimizing these parameters, the system achieves sharp focus and minimizes stray light effects, improving measurement accuracy without requiring complex testing procedures
2Measurement precision
If pinhole is provided to minimize the angle over which light can enter the eye, then optical degradation is reduced, but light transmission to the retina is further reduced
Solution Approach 1:
The patent changes the wavelength parameter of the illumination light to near-infrared range, which penetrates the optical media more effectively and reduces scattering. This allows for larger effective pupil aperture without the same degree of optical degradation, thereby maintaining both image quality and light transmission levels
Solution Approach 2:
The patent replaces the mechanical pinhole aperture with an optical filtering and illumination control system. Instead of physically blocking light paths, the system uses wavelength-selective illumination and optical conditioning to achieve similar optical degradation reduction while preserving light transmission
3Measurement precision
If wavefront sensor measurements and adaptive optics are used to correct optical errors, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent implements partial adaptive optics correction, focusing on correcting only the most significant optical aberrations (lower-order aberrations) rather than attempting to correct all higher-order aberrations. This partial correction approach achieves substantial improvement in measurement accuracy while keeping the system complexity manageable
Solution Approach 2:
The patent segments the optical correction function into separate components: wavefront sensing as one module and adaptive optics correction as another. This segmentation allows for independent optimization of each component and simplifies the overall system architecture, making the complex functionality more manageable and maintainable
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 approach provides accurate and efficient measurement of visual function by minimizing optical errors, improving fixation stability, and quantifying potential vision, thereby enhancing treatment decisions for retinal diseases.
Implementation Method 1
video rate near infrared retinal imaging to pinpoint fixation location and assess fixation stability
Implementation Method 2
near infrared retinal imaging
Implementation Method 3
wavefront sensor measurements to correct optical errors beyond sphere and cylinder
Implementation Method 4
projects visual targets through a fixed pupil size to minimize light scatter and aberrations
Implementation Method 5
minimize the angle over which light can enter the eye and the cross section of the pupil that can transmit light
Implementation Method 6
optical factors such as stray light, poor transmission, and lack of sharp focus
Data Source
AI summary
Methods, systems, and devices to improve the assessment of visual function and overcoming limitations of current methods to identify the visual function that potentially could be reached by a given eye. Multiple eye tests including visual stimuli plus optical measurement components, and methods to combine the results, identify and quantify sources of decreased vision resulting from optical sources, such as a lens and cornea as distinguished from retinal sources. By identifying potentially correctable optical sources of decreased vision, and overcoming physiological limitations such as size of the eye's pupil, the visual benefits of treatment such as by cataract or corneal surgery are distinguished from retinal pathology that requires medical intervention. The devices and methods provide metrics that include an expected value of the visual function and sources of variability including both optical and neural components, to guide treatment and improve clinical trials.