Animated Fixation Targets for Fundus Camera Alignment
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Solution Overview
Problem
Conventional fundus photography techniques face challenges in achieving accurate optical alignment of the eye with the fundus camera, particularly due to small pupil size and micro-saccadic movements, leading to inconsistent fixation and poor image quality.
Innovation Solution
The implementation of a fundus camera with a display that projects animated fixation targets onto the examinee's eye, dynamically adjusted within a fixation zone to guide the eye towards optical alignment, combined with a tracking camera to monitor pupil size and alignment, allowing for optimized image capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single fixation point is used for alignment, then the examinee can focus on a specific target, but micro-saccadic movements cause inconsistent fixation and poor image quality
Solution Approach 1:
The patent transforms the static fixation point into a dynamic animated target that moves within a fixation zone. The animation compensates for micro-saccadic movements by continuously updating the target position, thereby maintaining reliable fixation throughout the image capture process while preserving alignment accuracy.
Solution Approach 2:
The system incorporates eye tracking feedback to monitor the examinee's gaze position in real-time. This feedback mechanism allows the animated fixation target to adjust its position dynamically, ensuring that the examinee's line of sight remains aligned with the optical axis despite natural eye movements, thus resolving the contradiction between precision and stability.
2Ease of operation
If the pupil size is small, then the examinee can maintain natural eye state without dilation, but achieving accurate optical alignment becomes extremely difficult
Solution Approach 1:
The patent introduces a spatial dimension by creating a fixation zone rather than a single point. This zone provides a larger target area that is easier to acquire and maintain with small pupils, while the animated target within the zone maintains precise alignment guidance. This dimensional expansion resolves the contradiction between ease of operation and measurement precision.
3Device complexity
If conventional alignment methods are used, then the equipment setup is simple, but the alignment process is difficult and time-consuming requiring trained operators
Solution Approach 1:
The system implements self-aligning capabilities through animated fixation targets and real-time eye tracking feedback. The examinee independently completes the alignment process by following the animated target, eliminating the need for trained operators to manually adjust alignment. This self-service approach maintains equipment simplicity while dramatically improving ease of operation.
4Measurement precision
If intense focus is required on a single fixation point, then alignment can be achieved, but the examinee experiences discomfort and micro-saccadic movements
Solution Approach 1:
The patent employs periodic animation of the fixation target, creating a rhythmic visual stimulus that is more comfortable for the examinee to follow. This periodic motion reduces the strain of maintaining intense focus on a static point, decreasing discomfort and micro-saccadic movements while preserving fixation accuracy through the animated guidance.
Data Source
AI summary
The technology described herein is directed to a fundus camera and, more specifically, to a fundus camera having a display that projects active visual alignment stimuli onto an eye of an examinee via one or more components of an optimal assembly. The active visual alignment stimuli are dynamically adjusted to guide an examinee toward optical alignment for fundus imaging.