Slit Lamp Eye Imaging Device for Undilated Pupil Retinal Analysis
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Solution Overview
Problem
Current ophthalmic imaging devices are expensive, difficult to align, and produce poor image quality, especially when imaging through undilated or small pupils, limiting their adoption in general ophthalmology and optometry due to issues with reflections and artifacts.
Innovation Solution
A slit lamp-mounted eye imaging device with a converging light illumination system, aperture stops, and digital camera subsystem that allows wide field and magnified retinal imaging through undilated or dilated pupils, using off-axis illumination and image processing to eliminate artifacts and glare, and auto-sensing pupil size for optimal image capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional fundus cameras or slit lamp imaging systems are used, then retinal imaging can be performed, but the devices are expensive, difficult to align, and produce poor image quality with artifacts and reflections
Solution Approach 1:
The device separates the illumination system from the imaging path, using a beam splitter to combine them. The illumination source is positioned off-axis and directed through the beam splitter to illuminate the retina without blocking the imaging path, allowing independent optimization of illumination and imaging components
Solution Approach 2:
A beam splitter serves as an intermediary element that allows illumination light to reach the retina while simultaneously allowing reflected light from the retina to reach the camera. This intermediary component resolves the conflict between needing strong illumination and maintaining clear imaging path
2Area of stationary object
If annulus illumination is used in fundus cameras, then wide field illumination is achieved, but larger pupil size is required and alignment to patient's pupil becomes difficult
Solution Approach 1:
The illumination source is positioned off-axis rather than symmetrically on the optical axis. This asymmetric positioning allows the illumination beam to enter the eye at an angle, enabling wide field illumination while maintaining compatibility with smaller, undilated pupils and simplifying alignment procedures
Solution Approach 2:
The illumination is delivered in a converging conical beam rather than as a planar annulus. This three-dimensional conical illumination pattern allows wide angular coverage of the retina while the physical footprint of the illumination aperture remains small, enabling undilated pupil imaging
3Device complexity
If point source illumination is used, then device complexity is reduced, but field of view is severely limited and optical artifacts are present
Solution Approach 1:
The system uses a static point source illumination that creates dynamic illumination patterns across the retina through the patient's eye movements and fixation changes. This allows a simple point source to effectively illuminate and image a wide field of view without requiring complex scanning mechanisms
4Adaptability or versatility
If scanning laser systems are used, then specialized diagnostic functionality is provided, but the systems are expensive and do not offer color imaging modes
Solution Approach 1:
The device uses a single broadband illuminator that can provide multiple wavelengths for different imaging modes (color fundus, red-free, infrared) without requiring separate laser sources for each modality. This universal illumination approach enables cost-effective multi-functional imaging capability
Solution Approach 2:
The system achieves different imaging modalities by changing the spectral parameters of the illumination source rather than using different laser systems. By selecting appropriate wavelength bands from a broadband source, the device provides multiple diagnostic functions including color imaging, red-free imaging, and infrared imaging at lower cost
5Area of stationary object
If pharmacological dilation is used to improve retinal examination, then pupil size increases for better imaging, but it is not always possible or convenient for patients
Solution Approach 1:
The device is designed to automatically adapt to the patient's natural pupil size through auto-sensing capabilities. The system self-adjusts illumination aperture and imaging parameters based on the detected pupil diameter, eliminating the need for pharmacological dilation while maintaining optimal image quality
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 device provides high-quality, artifact-free retinal images through small pupils, increasing accessibility and usability in clinical settings while reducing costs and complexity, enabling wider field views without the need for pharmacological dilation.
Implementation Method 1
The converging light illumination system may be made up of one or more light sources, or a single shifting or rotating light source, such as an LED
Implementation Method 2
Aperture stops, position of optics, and/or off-axis illumination blocks unwanted reflections or glare from being formed in the retinal image
Implementation Method 3
The device provides entry of light rays into the eye, wide field retinal illumination, reduced glare, and elimination of artifacts and ghost reflections
Data Source
AI summary
A slit lamp mounted eye imaging device for viewing wide field and/or magnified views of the retina or the anterior segment through an undilated or dilated pupil. The apparatus images posterior and anterior segments of the eye, and sections/focal planes in between and contains an illumination system that uses one or more LEDs, shifting optical elements, and/or aperture stops where the light can be delivered into the optical system on optical axis or off axis from center of optical system and return imaging path from the retina, thereby creating artifacts in different locations on retina. Image processing is employed to detect and eliminate artifacts from images. The device is well suited for retinal imaging through an undilated pupil, non-pharmacologically dilated, or a pupil as small as 2 mm. Two or more images with reflection artifacts can be created and subsequently recombined through image processing into a composite artifact-free image.