Eye Measuring Apparatus Sequential Light Point Activation
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Solution Overview
Problem
Existing eye measuring apparatuses face challenges in accurately determining corneal thickness due to the need to focus on multiple planes, assumptions about corneal symmetries leading to inaccuracies, and the requirement for sequential image capture which can introduce uncertainty due to eye displacement.
Innovation Solution
The apparatus employs a stimulator with multiple light points to illuminate the cornea, a camera system to capture reflected images, and a computational unit to analyze the posterior surface of the cornea by selectively activating different subsets of light points and combining corresponding reflected images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If all stimulator light points are activated simultaneously to illuminate the cornea, then the illumination level is high enough to capture clear reflected images, but background reflections from iris, cataract, and other structures increase significantly, reducing the clarity of posterior surface reflections
Solution Approach 1:
The stimulator light points are divided into multiple subsets that are activated sequentially rather than simultaneously. Each subset contains a specific number and arrangement of light points that are activated in separate time intervals, allowing the camera to capture reflected images from different illumination patterns. This segmentation reduces background reflections while maintaining sufficient illumination for clear image capture.
Solution Approach 2:
The stimulator light points are activated in periodic cycles, with different subsets being activated in sequential time intervals. Each activation cycle illuminates a specific subset of light points, and the camera captures reflected images during each interval. This periodic activation pattern allows the system to accumulate multiple images with varying illumination levels and angles, improving the signal-to-noise ratio for posterior surface reflections while minimizing background interference.
2Illumination intensity
If multiple images are captured sequentially to determine corneal thickness, then different illumination levels can be used for anterior and posterior surfaces, but eye displacement between captures introduces uncertainty in position alignment
Solution Approach 1:
The system uses feedback from reflected images of known stimulator light point positions to detect and correct eye displacement. By comparing the positions of reflected light points across multiple images, the system can calculate the degree of eye movement and apply corrective transformations to align images before processing, thereby maintaining measurement precision despite sequential capture.
Solution Approach 2:
The system captures multiple copies of the corneal surface from different illumination angles and time points. Instead of requiring a single perfect image, the system accumulates multiple image copies that are then processed together. These multiple copies provide redundant information that can be used to compensate for displacement and improve the accuracy of corneal thickness determination.
3Shape
If a Placido ring illuminator is used to illuminate the cornea, then the anterior surface can be imaged, but assumptions about corneal symmetries are required which may not be present in reality, introducing inaccuracies
Solution Approach 1:
The system uses multiple stimulator light points arranged in asymmetric patterns rather than symmetric ring structures. By activating different subsets of light points in various arrangements, the system can illuminate and capture images of the corneal surface without requiring symmetry assumptions. The multiple asymmetric illumination patterns provide sufficient geometric information to reconstruct the corneal shape accurately regardless of its actual symmetry properties.
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
This approach allows for improved analysis of the posterior surface of the cornea by reducing background reflections and enhancing illumination levels, resulting in more accurate determination of corneal thickness and other eye characteristics.
Implementation Method 1
a stimulator comprising multiple stimulator light points for projecting a plurality of light rays onto a surface of the cornea of an eye; a camera system for capturing reflected images of the stimulator light points
Data Source
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AI summary
The present invention relates to an eye measuring apparatus, comprising: a stimulator comprising multiple stimulator light points for projecting a plurality of light rays onto a surface of the cornea of an eye; a camera system for capturing reflected images of the stimulator light points; and a computational unit arranged to analyse the posterior surface of the cornea and/or to obtain a characteristic of the eye on the basis of the reflected images. The control unit is arranged to activate subsequently different subsets of the multiple stimulator light points. The control units is further arranged to carry out the following steps: selecting, for each of the different subsets of the multiple stimulator light points, at least one reflected image that corresponds with activation of the respective subset of the multiple stimulator light points, and combining the selected reflected images with each other to analyse the posterior surface of the cornea and/or to obtain the characteristic of the eye.