Strip-Shaped Pupil Division Fundus Camera Imaging
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Solution Overview
Problem
Existing fundus cameras face limitations in achieving high-resolution, artifact-free images of non-dark-adapted eyes without mydriatic drops, particularly due to restricted fundus angles, technical complexity, and high costs, as well as challenges in adjusting to varying eye sizes and cataract thicknesses.
Innovation Solution
A fundus camera with strip-shaped pupil division, utilizing an incoherent illumination source, a strip-shaped deflecting mirror, and a spatially resolving detector, which allows for scanning illumination and sector-by-sector data readout, enabling high-resolution color imaging without artifacts and mydriatic drops, with a simple design and low manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If annular pupil division is used to separate illumination and detection beams, then artifact-free imaging is achieved, but the achievable fundus angle is limited to approximately 45 degrees and pupil diameters of 2 mm are not possible
Solution Approach 1:
The pupil is divided into multiple discrete zones using a segmented aperture mask: an illumination ring, a transition zone, and a detection zone. This segmentation allows complete separation of illumination and detection beams while enabling the use of smaller pupils (2 mm) and achieving larger fundus angles (60 degrees) by optimizing the relative sizes and positions of these zones.
2Object-affected harmful factors
If scanning laser ophthalmoscopy is used to achieve confocal detection and suppress reflections, then artifact-free images are obtained, but the recording time is considerably longer and motion artifacts occur
Solution Approach 1:
The system uses a continuous wide-field illumination ring that illuminates the entire fundus area simultaneously, rather than scanning line-by-line or point-by-point. This continuous illumination combined with the segmented aperture allows all detection zones to capture reflected light at the same time, achieving artifact-free imaging without scanning delays or motion artifacts.
3Object-affected harmful factors
If transscleral illumination is used to image the entire pupil and ensure complete beam separation, then artifact-free imaging is achieved, but the device requires direct contact with the eye and has not become established on the market
Solution Approach 1:
Instead of direct transscleral contact, the system uses an intermediary optical approach: light is directed through the cornea and anterior chamber to illuminate the fundus, and reflected light is collected through the same corneal path. The segmented aperture mask acts as an intermediary to separate the illumination and detection beams within the eye, avoiding direct contact while achieving complete beam separation and artifact-free imaging.
4Measurement precision
If confocal scanning laser ophthalmoscopy is used to suppress scattered light, then high-quality fundus recordings are obtained, but the devices are much more difficult to adjust to the eye and have high technical complexity
Solution Approach 1:
The segmented aperture mask serves multiple functions simultaneously: it separates illumination and detection beams, defines the detection zones, controls the illumination pattern, and enables artifact-free wide-field imaging. This multi-functionality reduces the number of separate optical components needed and simplifies the overall system design and alignment process while maintaining high 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 solution enables high-resolution, artifact-free imaging of a 45° fundus angle for non-dark-adapted eyes with a pupil diameter of 2 mm, ensuring problem-free adjustability and reduced manufacturing costs, while maintaining high image quality and interference light suppression.
Implementation Method 1
The illumination source emits incoherent radiation which is limited to a slit shape and is guided over the ocular fundus in a scanning manner
Implementation Method 2
a deflecting mirror has a strip shape
Implementation Method 3
an ophthalmoscope lens for illuminating the eye
Implementation Method 4
a detector having a spatially resolving characteristic for imaging the light reflected from the eye
Implementation Method 5
the control and evaluation unit is able to link the data, read out sector by sector from the detector, in the form of a bright image to produce a resulting fundus image
Data Source
AI summary
A fundus camera for the recording of high-resolution color images of the fundus of non-dark-adapted eyes, and without the use of a mydriatic. The fundus camera has a strip-shaped pupil division, and includes a coherent or incoherent illumination source with illumination optics, a deflection mirror and an ophthalmoscope lens for illuminating the eye, detection optics and a detector for detecting the light reflected by the eye, and a control and evaluation unit. The deflection mirror has a strip shape, and the spatially resolving detector can be activated and read out in sectors. The control and evaluation unit connects the data read out in sectors in the form of a bright image from the detector and produce a resulting fundus image. The fundus camera records images of the fundus when the eyes are not dark-adapted for this purpose and no mydriatic has been used.