Aperture-optional Head-mounted Fundus Camera
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Solution Overview
Problem
Conventional fundus cameras are large, expensive, non-portable, and uncomfortable for patients due to the need for still positioning and bright trans-pupillary illumination, with challenges in image capture quality due to dexterity requirements and optical artifacts like glares and haloes.
Innovation Solution
A head-mounted, aperture-optional low-light fundus imaging device that uses non-pupillary illumination and reduces mechanical and optical components, allowing for improved image capture without the need for manual alignment and minimizing visual artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional fundus cameras use bright trans-pupillary illumination to illuminate the fundus, then the fundus can be adequately illuminated for imaging, but patients experience discomfort and visual artifacts such as glares and haloes are captured
Solution Approach 1:
The illumination and imaging paths are segmented into separate optical channels. The illumination light enters through the pupil to illuminate the fundus, while the imaging path captures reflected light from the fundus without including the illumination source in the field of view. This spatial segmentation prevents glare and halo artifacts while maintaining adequate fundus illumination.
Solution Approach 2:
The system transitions from a single-axis trans-pupillary illumination approach to a multi-dimensional optical configuration where illumination and imaging occur in different spatial dimensions. The illumination path and imaging path are separated in 3D space, allowing independent optimization of each path without interference.
2Measurement precision
If fundus cameras require manual alignment with the pupil opening, then image capture can be achieved, but the device becomes complex and requires trained operators due to dexterity challenges
Solution Approach 1:
The device performs self-alignment through automated optical tracking and pupil detection systems. The camera automatically tracks the pupil position and adjusts the optical path accordingly, eliminating the need for manual alignment by operators. This self-aligning mechanism reduces operational complexity while maintaining precise image capture.
Solution Approach 2:
Manual mechanical alignment is replaced with automated optical and electronic systems. Sensors detect pupil position and trigger electronic actuation of optical components to maintain alignment, substituting manual dexterity requirements with automated detection and adjustment mechanisms.
3Measurement precision
If fundus cameras incorporate complex optical and mechanical systems to improve image capture, then image quality can be enhanced, but the device size, weight, and cost increase
Solution Approach 1:
Optical components are designed to perform multiple functions simultaneously. For example, the same optical elements serve both illumination and imaging purposes at different wavelengths or angles, reducing the total number of components needed. This multi-functionality maintains image quality while reducing overall device weight and complexity.
Solution Approach 2:
Optical components are arranged in a nested or folded configuration where elements are positioned within each other's spatial envelopes. This compact nesting reduces the overall device footprint and weight while maintaining the necessary optical path lengths for high-quality imaging.
4Object-affected harmful factors
If fundus cameras use polarizers in the imaging and illumination paths to mitigate artifacts, then some glares and haloes can be reduced, but the device complexity and cost increase
Solution Approach 1:
The system converts the potentially harmful reflected illumination light into useful information by using it for optical coherence tomography (OCT) measurements. The same light that causes glare in traditional fundus photography is captured by OCT sensors to provide additional diagnostic information about retinal layers, transforming an artifact into a beneficial diagnostic feature.
Data Source
AI summary
An aperture-optional head-mounted low-light fundus camera is provided. A fundus camera is configured to enclose a patient's eyes, orient imaging paths of image sensors and lenses towards the patient's eyes without requiring integral aperture stops within the enclosure, and provide non-pupillary low-light illumination for fundus imaging within the enclosure. The aperture-optional head-mounted low-light fundus camera can be worn by a patient during use without limiting the patient's movement or posture, alleviating awkwardness and discomfort caused to the patient by conventional fundus cameras. The aperture-optional head-mounted low-light fundus camera further improves image capture quality over conventional fundus cameras, by removing the need to use dexterity to align with eye pupil, minimizing image blur from errant movement, and eliminating visual artifacts from glares, haloes, reflections, and the like.