Self-Aligning Fundus Camera with Dedicated Alignment Target
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Solution Overview
Problem
Conventional fundus cameras are limited by size, cost, and complexity, requiring trained operators and pupil dilation for accurate alignment, which restricts the availability and effectiveness of wide-field fundus imaging for retinal disease screening and monitoring.
Innovation Solution
A self-aligning fundus camera system with an alignment target and fixation target, using concentric illuminated shapes to guide users for precise self-alignment, reducing the need for operators and enabling wide-field, non-mydriatic imaging by combining illumination, imaging, and alignment paths, and incorporating eye tracking mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional fundus cameras use complex optical designs to avoid corneal and iris reflections, then imaging quality is improved, but device complexity and alignment difficulty increase
Solution Approach 1:
The patent extracts the alignment function into a separate, dedicated alignment target that projects alignment markers visible to the user. This separates the alignment path from the imaging path, allowing the imaging optics to focus solely on capturing high-quality fundus images without the complexity of integrated alignment mechanisms.
Solution Approach 2:
The alignment target acts as an intermediary element between the user and the imaging system. It provides visual feedback through alignment markers that guide the user to properly position their eye, mediating the alignment process without requiring complex optical designs in the main imaging path.
2Measurement precision
If conventional fundus cameras require trained operators for alignment, then alignment precision is improved, but ease of operation deteriorates
Solution Approach 1:
The system enables self-alignment by providing the user with direct visual feedback through alignment markers projected by the alignment target. The user can independently adjust their eye position to center the markers without requiring a trained operator, making the system self-serviceable and significantly improving ease of operation.
Solution Approach 2:
The alignment target provides real-time visual feedback to the user through alignment markers. When the user's eye is properly positioned, the markers appear centered and clear; when misaligned, the markers shift or become distorted. This immediate feedback loop enables users to self-correct their positioning, eliminating the need for operator intervention.
3Ease of operation
If separate fixation path with pinhole masks is used for self-imaging, then ease of operation is improved, but imaging field-of-view and imaging yield deteriorate
Solution Approach 1:
The system segments the optical path into distinct alignment and imaging functions. The alignment target handles only the alignment function with pinhole masks, while the main imaging optics are optimized separately for wide-field fundus imaging. This segmentation allows each subsystem to be optimized for its specific function without compromising the other.
Solution Approach 2:
The patent merges the alignment target output with the main imaging path at a strategic point where the alignment markers can be viewed by the user without interfering with the fundus imaging process. This combining allows both functions to coexist, enabling the system to provide both self-alignment capability and wide-field imaging.
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 compact, cost-effective, and user-friendly wide-field fundus imaging, reducing background noise and corneal/iris reflections, allowing for self-imaging of the retina without trained operators, suitable for screening and monitoring of retinal diseases.
Implementation Method 1
an alignment target configured to output an alignment image through the eyepiece to a user's eye
Implementation Method 2
illuminate the retina with illumination light and to capture reflected light from the retina with the image sensor
Data Source
AI summary
A fundus camera and method of operating the fundus camera are described. The fundus camera includes an image sensor, an eyepiece lens, an illumination source, and an alignment target. The image sensor captures image light of a retina within an eye. The eyepiece lens is disposed to pass the image light of the retina to the image sensor. The illumination source is disposed to direct illumination light onto the retina through the eyepiece lens. The illumination source is further disposed around a first aperture through which the image light of the retina passes from the eyepiece lens to the image sensor. The alignment target is coupled to output an alignment image through the eyepiece lens to the eye and disposed around a second aperture through which the image light of the retina is passed to the image sensor and the illumination light is passed to the eyepiece lens.