Model Eye Retinal Cup for Widefield Imaging Calibration
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Solution Overview
Problem
Conventional model eyes for fundus cameras lack sufficient features for accurate characterization and calibration, particularly in addressing distortion and magnification issues in widefield and ultra widefield imaging, and do not adequately represent diverse eye conditions.
Innovation Solution
A model eye system with a retinal cup featuring resolution targets, field of view rings, color calibration dots, and platform regions of varying heights to evaluate spatial resolution, depth of field, autofocus, and simulate emmetropic, myopic, and hyperopic eyes, using geometric transformations to correct optical distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional model eyes with simple painted patterns or photorealistic fundus are used, then the device complexity is reduced, but the measurement precision and characterization accuracy are insufficient
Solution Approach 1:
The model eye is divided into multiple functional regions with specific features: resolution targets for spatial frequency measurement, color calibration dots for color accuracy, field of view rings for FOV characterization, and platform regions at different heights for depth of field and autofocus testing. Each segment serves a specific measurement purpose, enabling comprehensive characterization without requiring an overly complex overall structure.
Solution Approach 2:
The model eye integrates multiple measurement capabilities into a single device that can characterize various aspects of fundus camera performance including spatial resolution, color accuracy, field of view, depth of field, and autofocus. This multi-functional design eliminates the need for multiple separate calibration devices while maintaining high measurement precision across all parameters.
2Adaptability or versatility
If existing model eyes are used, then the manufacturing cost is reduced, but they do not adequately represent diverse eye conditions and optical distortions
Solution Approach 1:
The model eye incorporates features at specific locations that correspond to different retinal regions and optical conditions. Platform regions at varying heights simulate different focal planes and depth of field characteristics, while resolution targets positioned at specific locations test spatial resolution across the field of view. This localized quality variation enables accurate representation of diverse eye conditions and optical distortions.
Solution Approach 2:
The model eye uses geometric transformations and varying physical parameters (such as platform heights, dot sizes, and color combinations) to simulate different optical conditions including emmetropic, myopic, and hyperopic states. By changing these parameters, the single model eye can represent multiple eye conditions without requiring multiple separate models, maintaining both versatility and manufacturing precision.
3Area of stationary object
If widefield and ultra widefield imaging is used, then the field of view is improved, but distortion and magnification errors increase in peripheral areas
Solution Approach 1:
The model eye uses three-dimensional platform regions at different heights to characterize depth of field and focus performance across the wide field of view. This adds a vertical dimension to the measurement, enabling assessment of optical performance in peripheral areas that would otherwise be difficult to evaluate. The 3D structure allows measurement of distortion and magnification effects across the entire field without sacrificing precision.
Data Source
AI summary
A model eye for evaluating a retinal imaging system includes a retinal cup and a resolution target. The retinal cup includes an interior surface having a bowl-like shape to represent a fundus of a human eye. The resolution target is disposed on the interior surface for assessing a spatial resolution of the retinal imaging system. The resolution target includes light and dark contrasting regions with straight edges separating the light and dark contrasting regions. At least two of the straight edges are orthogonal. An array of dark color microfeatures may be disposed in the light contrasting region and an array of light color microfeatures may be disposed in the dark contrasting region. The light and dark color microfeatures are variably sized for assessing the spatial resolution of the retinal imaging system.