Variable Focus Lens Through-Focusing Fundus Imaging

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Solution Overview

Problem

Current diabetic retinopathy screening methods require pharmacological pupil dilation, which can be painful and inconvenient, and are limited by ambient light conditions, making non-mydriatic fundus imaging challenging, especially in low-light environments.

Innovation Solution

A fundus imaging system that uses a variable focus lens, near-infrared illumination, and passive eye tracking to capture high-quality images of the retina without mydriasis, allowing for rapid image capture across different diopter ranges and enabling imaging in low-light conditions without the need for pharmacological pupil dilation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If pharmacological pupil dilation is used for fundus imaging, then image quality and diagnostic accuracy are improved, but patient comfort deteriorates and procedure complexity increases

Engineering Contradiction:
Improveimage qualityVSAvoidpatient comfort
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent extracts and eliminates the need for pharmacological pupil dilation from the fundus imaging process. By using near-infrared illumination and optimized optical pathways, the system achieves high-quality retinal images without requiring mydriatic agents, thereby removing the source of patient discomfort while maintaining diagnostic accuracy

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the wavelength parameter of illumination light to near-infrared range (700-900 nm), which allows deeper penetration into ocular tissues and enables high-quality imaging without pupil dilation. This parameter change fundamentally alters the interaction between light and ocular media, improving both image quality and patient comfort

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If non-mydriatic fundus imaging is performed in low-light environments, then patient comfort is improved, but image quality and capture speed deteriorate

Engineering Contradiction:
Improvepatient comfortVSAvoidimage capture speed
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent employs rapid sequential capture of multiple images at different focus settings (through-focusing technique) and combines them through image processing. This periodic action at high speed compensates for the lack of pupil dilation, enabling sufficient light gathering while maintaining patient comfort and achieving high-quality composite images

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system continuously captures images across a range of diopter settings in rapid succession, ensuring that useful imaging action continues throughout the process. This continuous through-focusing approach maximizes light utilization and maintains image capture speed even without pharmacological dilation

Inventive Principle:
Principle #20Continuity of useful action

3Adaptability or versatility

If through-focusing technique with multiple diopter ranges is used, then comprehensive retinal coverage is improved, but image processing complexity increases

Engineering Contradiction:
Improveretinal coverageVSAvoidimage processing complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent captures multiple copies of the retinal image at different focus settings (diopter ranges) and then processes them to create a single composite image with extended depth of field. This copying approach at multiple focal planes enables comprehensive retinal coverage while automated processing algorithms manage the complexity of combining these copies

Inventive Principle:
Principle #26Copying

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 efficient and pain-free diabetic retinopathy screening and monitoring of other eye diseases like hypertension and glaucoma, providing clear, detailed images in low-light environments without the need for mydriatic drugs, improving patient comfort and diagnostic accuracy.

Implementation Method 1

The variable focus lens is set to a first diopter range that corresponds to a first depth zone and a second diopter range that corresponds to a second depth zone

Methodology Applied
Scientific EffectOptical focusing: Lens

Implementation Method 2

A fundus imaging system that uses a variable focus lens, near-infrared illumination

Methodology Applied
Scientific EffectNear-infrared radiation: Infrared Radiation

Data Source

PatentEP3261518B1Through focus retinal image capturing
Publication Date: 2024.11.27 WELCH ALLYN INC
  • EP3261518B1 patent drawingFigure 1
  • EP3261518B1 patent drawingFigure 2
  • EP3261518B1 patent drawingFigure 3

AI summary

An apparatus for producing a non-mydriatic fundus image is disclosed. The apparatus can include a processor and memory, as well as an illumination component and a camera with a variable focus lens. The apparatus can be configured to adjust the focus of the lens to a plurality of different diopter ranges and capture at least one image at each of the plurality of different diopter ranges. A method for capturing a non-mydriatic image of a fundus is also disclosed. The method can include setting a depth of field, dividing the depth of field into a plurality of zones, adjusting a variable focus lens of a camera to focus on each of the plurality of zones, and capturing at least one image at each of the plurality of zones.