Portable Retinal Imaging With Annular Illumination and Liquid Focusing
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Solution Overview
Problem
Existing fundus imaging systems for neonatal subjects are cumbersome, heavy, inefficient, difficult to maneuver, and produce images with distortion and low contrast, particularly when performing fundus fluorescein angiography due to the absence of a crystalline lens in premature babies.
Innovation Solution
A compact, lightweight imaging system using a molded light guide with alternating LEDs for annular light, a planar annular filter, and a motor-controlled green barrier filter, combined with a liquid lens and imaging optics to achieve high-contrast angiographic images and reduce distortion, capable of performing both fundus fluorescein angiography and photography without manual adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If conventional fundus imaging systems are used for neonatal subjects, then imaging function is provided, but the systems are cumbersome, heavy, and difficult to maneuver
Solution Approach 1:
The imaging system is divided into separate functional modules: a portable imaging unit with contact lens assembly, a separate computing device for image processing, and optional handheld stabilizing devices. This segmentation allows the main imaging component to be lightweight and easy to maneuver while distributing other functions to separate components.
Solution Approach 2:
A handheld stabilizing device acts as an intermediary between the operator and the imaging system, providing mechanical stabilization without adding significant weight to the imaging unit itself. The stabilizing device mediates between the need for steady imaging and the requirement for portability.
2Use of energy by moving object
If conventional imaging systems are used, then imaging is possible, but energy efficiency is poor
Solution Approach 1:
The imaging system uses flash-based illumination rather than continuous lighting, providing light only during the brief moment when images are captured. This periodic action dramatically reduces energy consumption compared to continuous illumination while maintaining sufficient operational duration through efficient use of power during imaging intervals.
3Manufacturing precision
If standard imaging optics are used, then imaging is achieved, but image distortion is high
Solution Approach 1:
The contact lens assembly uses asymmetric optical elements and non-standard lens configurations to correct for the unique optical characteristics of neonatal eyes, which differ significantly from adult eyes. This asymmetric design addresses distortion specific to the smaller, developing eye geometry without requiring complex multi-element systems.
Solution Approach 2:
The optical system parameters (focal length, aperture, lens curvature) are specifically optimized for neonatal eye dimensions and optical properties rather than using standard adult eye parameters. This parameter adjustment reduces distortion by matching the optical design to the actual physiological characteristics of the target subject.
4Adaptability or versatility
If the system is designed for neonatal use only, then specialized imaging is achieved, but versatility is reduced
Solution Approach 1:
The imaging system incorporates adjustable optical parameters and interchangeable components that allow it to adapt to different subject types (neonates, infants, adults). The contact lens assembly and optical system can be reconfigured for different eye sizes and optical characteristics, enabling a single system to serve multiple patient populations without requiring complete redesign.
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
The system provides high-contrast, low-distortion images suitable for both premature and full-term subjects, enhancing diagnostic accuracy and ease of use by reducing weight, energy consumption, and operational complexity.
Implementation Method 1
The fundus is then illuminated with a blue light. This blue light reacts with the dye in the blood in the blood vessels in the retina and emit green light.
Implementation Method 2
The system employs a moulded light guide to form an annular light source
Implementation Method 3
The system further employs a green barrier filter in the path of the light from the eye for filtering subject before it reaches the reaching an image sensor that captures an image.
Data Source
AI summary
Preterm babies have a high risk of retinopathy. Doctors conduct fundus fluorescein angiography to determine the state of the blood vessels in their retinas. Disclosed is a system (100) for conducting fundus fluorescein angiography configured for light weight, small size, and providing a sharp, high contrast angiograph. The disclosed system uses a moulded annular light source, blue and white LEDs (120) for providing the illumination, an planar annular emission filter (125) for filtering the blue light, and imaging optics (130) configured for reducing aberration. The imaging optics (130) comprises a mechanical iris (136) to control the amount of light reaching an image sensor (150), a tuneable liquid lens (141) for focusing the image, a green barrier filter (146) that may be removed from the path of the light—for conducting fundus photography. The white LEDs and the mechanical iris (136) may be used for conducting fundus photography.