Non-Mydriatic Fundus Imaging via Variable Focus Lens
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Solution Overview
Problem
Current diabetic retinopathy screening methods require pharmacological pupil dilation, which can be painful and inconvenient, and struggle with effective imaging in low-light environments, limiting the ability to capture clear fundus images without mydriatic drugs.
Innovation Solution
A non-mydriatic fundus imaging system that uses a variable focus lens and near-infrared illumination to capture images at multiple diopter ranges, allowing for pupil position alignment and depth of field focus without autofocusing, enabling rapid image capture and reducing patient discomfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pharmacological pupil dilation is used for fundus imaging, then image quality is improved, but patient comfort deteriorates and procedural complexity increases
Solution Approach 1:
The patent removes the requirement for pharmacological pupil dilation from the imaging process. By using a variable focus lens system that captures images at multiple diopter ranges, the system achieves clear fundus images without needing to dilate the pupil, thereby eliminating the associated patient discomfort and procedural complexity while maintaining diagnostic image quality
Solution Approach 2:
The patent changes the imaging parameter from fixed-focus to variable focus across multiple diopter ranges. By capturing images at different focus settings (e.g., -3D to +3D in 1D increments), the system ensures that at least one image will be in focus regardless of the patient's natural pupil state, eliminating the need for pharmacological dilation while maintaining image quality
2Ease of operation
If non-mydriatic fundus imaging is performed in low-light environments, then patient comfort is improved, but image capture reliability deteriorates
Solution Approach 1:
The patent performs preliminary actions by capturing a series of images at multiple diopter ranges before selecting the final diagnostic image. This preliminary multi-focus capture ensures that regardless of lighting conditions or pupil state, at least one image will be properly focused and suitable for diagnosis, thereby maintaining reliability without requiring mydriatics
Solution Approach 2:
The system uses feedback by evaluating multiple captured images at different diopter settings to determine which image is in focus. The processor analyzes the captured images and selects the appropriate focused image for diagnosis, ensuring reliable image capture even in low-light non-mydriatic conditions where pupil position may be unpredictable
3Reliability
If multiple images are captured at different diopter ranges, then focus reliability is improved, but productivity deteriorates
Solution Approach 1:
The patent employs a dynamic variable focus lens system that can rapidly adjust between different diopter ranges. This dynamic focusing capability allows the system to capture multiple images at different focus settings quickly, maintaining focus reliability while minimizing the time penalty through automated, rapid lens adjustment rather than manual focusing
Solution Approach 2:
The system maintains continuous useful action by capturing images continuously across the diopter range without interruption. Rather than pausing between captures or requiring manual intervention, the automated system sequentially captures images at predetermined diopter increments, ensuring focus reliability through multiple captures while maintaining productivity through continuous automated operation
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 clear and efficient fundus imaging without mydriatic drugs, facilitating the diagnosis and monitoring of diabetic retinopathy and other eye diseases in low-light conditions, while minimizing patient discomfort and procedural complexity.
Implementation Method 1
a variable focus lens and near-infrared illumination to capture images at multiple diopter ranges, allowing for pupil position alignment and depth of field focus without autofocusing
Implementation Method 2
a variable focus lens and near-infrared illumination to capture images at multiple diopter ranges
Data Source
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AI summary
Apparatus and methods of non-mydriatic fundus imaging are disclosed. Fundus imaging apparatus include an infrared light unit configured to illuminate during a fundus scan. Based on fundus scanning, a first focus position is determined. Fundus images are then captured starting at the first focus position. Focus of the fundus imaging apparatus is adjusted to a plurality of sequential diopters and images captured at each adjustment.