OCT Tracking System for Eye Motion Artifact Reduction

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Solution Overview

Problem

Current ophthalmic diagnostic systems face challenges in efficiently handling eye motion during data acquisition, leading to unusable data due to motion artifacts and prolonged acquisition times, as existing tracking methods struggle with sudden movements and axial motion, and lack user control for optimal data collection.

Innovation Solution

A system and method that continuously monitor fundus image quality to enable efficient tracking, allow for re-scanning based on predetermined criteria, and track motion in the axial direction, using a combination of fundus imaging and optical coherence tomography (OCT) systems to select the best reference frame and adjust data collection accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If tracking is used to correct for eye motion during data acquisition, then measurement precision is improved, but acquisition time increases considerably due to repeated scanning

Engineering Contradiction:
Improvemeasurement precisionVSAvoidacquisition time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary monitoring of fundus image quality before and during OCT data acquisition to detect eye motion in advance. By continuously monitoring the fundus image and detecting motion before it affects the OCT measurements, the system can preemptively adjust or retake scans, avoiding the need for extensive repeated scanning and reducing overall acquisition time while maintaining measurement precision.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If the tracker keeps retrying to acquire data when the eye is not stable, then measurement precision is maintained, but acquisition time increases

Engineering Contradiction:
Improvemeasurement precisionVSAvoidacquisition efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The system implements a feedback mechanism where fundus image quality is continuously monitored and used to control the OCT scanning process. When motion is detected in the fundus image, the system receives feedback to adjust scanning parameters or trigger retakes, creating a closed-loop system that optimizes the balance between maintaining measurement precision and improving acquisition efficiency based on real-time eye stability conditions.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If prior art tracking systems repeat one line of OCT measurement sequence until sufficient data is collected, then measurement precision is improved, but the system cannot handle large and sudden movements such as saccades

Engineering Contradiction:
Improvemeasurement precisionVSAvoidadaptability to sudden motion
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The system performs preliminary monitoring of fundus image quality before OCT data acquisition to detect eye motion in advance. By continuously monitoring the fundus image and detecting motion before it affects the OCT measurements, the system can preemptively adjust or retake scans, avoiding the need for extensive repeated scanning and reducing overall acquisition time while maintaining measurement precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts scanning parameters and retake decisions based on real-time fundus image quality monitoring. Rather than using a fixed repeat strategy, the system adapts its behavior to the current eye stability conditions, allowing it to handle both small gradual movements and large sudden movements like saccades effectively.

Inventive Principle:
Principle #15Dynamics

4Measurement precision

If existing tracking methods are used, then some motion is corrected, but data collected before tracker determination of motion contains artifacts and is unusable

Engineering Contradiction:
Improvemeasurement precisionVSAvoiddata usability
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The system implements a feedback mechanism where fundus image quality is continuously monitored and used to control the OCT scanning process. When motion is detected in the fundus image, the system receives feedback to adjust scanning parameters or trigger retakes, creating a closed-loop system that optimizes the balance between maintaining measurement precision and improving acquisition efficiency based on real-time eye stability conditions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary monitoring of fundus image quality before and during OCT data acquisition to detect eye motion in advance. By continuously monitoring the fundus image and detecting motion before it affects the OCT measurements, the system can preemptively adjust or retake scans, avoiding the need for extensive repeated scanning and reducing overall acquisition time while maintaining measurement precision.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2691008B1Systems and methods for efficiently obtaining measurements of the human eye using tracking
Publication Date: 2022.05.04 CARL ZEISS MEDITEC AG
  • EP2691008B1 patent drawingFigure 1~2
  • EP2691008B1 patent drawingFigure 3(a)~3(f)
  • EP2691008B1 patent drawingFigure 4~5

AI summary

Systems and methods for efficiently obtaining optical coherence tomography (OCT) measurement data with reduced effects of motion are presented. One embodiment of the present invention involves determining the amount of motion present during the collection of an OCT data set based on images of the eye collected at the same time as the OCT data, and recollecting select portions of the OCT data set when the amount of eye motion is determined to exceed a predetermined threshold. Additional aspects of the invention include enabling or disabling the tracking feature in the system based on the quality of the images available for tracking and tracking based on an image collected during a prior examination of the patient to allow repeat scanning at the same location. A further embodiment of the invention includes reducing the effect of motion in the axial or z-direction of the data based on a comparison to a model of the eye constructed from OCT data. The method can also be used to reduce the presence of mirror image artifacts in an OCT image.