Retinal Thickness Measurement Grid Alignment
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Solution Overview
Problem
Current ophthalmic diagnostics face challenges in accurately mapping retinal thickness measurements due to improper alignment of measurement loci with anatomical features, especially when the fovea is off-centered or the eye moves during examination, leading to errors in disease progression monitoring and diagnosis.
Innovation Solution
A method and apparatus that register a 3-D OCT volume dataset to a fundus image by identifying characteristic features, allowing a movable measurement grid to be superimposed and aligned with anatomical features, enabling accurate calculation of retinal thickness values within defined neighborhoods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If retinal thickness measurements are taken using fixed reference points (center of optic disc or fovea), then measurement consistency is improved, but measurement precision deteriorates when the fovea is off-centered or the eye moves during examination
Solution Approach 1:
The patent applies the dynamics principle by transforming the measurement system from a static fixed-grid approach to a dynamic adaptive approach. The measurement grid is no longer fixed at predetermined locations but dynamically repositioned based on the actual locations of anatomical landmarks (fovea and optic disc) detected in each patient's fundus image. This allows the system to adapt to eye movements and off-centered foveas, maintaining measurement precision across diverse patient conditions.
Solution Approach 2:
The patent implements parameter changes by modifying the measurement loci parameters based on detected anatomical feature locations. Instead of using fixed coordinates, the system calculates measurement grid positions as functions of the detected fovea and optic disc locations. This parameter adaptation ensures that measurements are always taken at anatomically correct locations, resolving the contradiction between measurement precision and adaptability to varying eye conditions.
2Measurement precision
If a fixed measurement grid is used for retinal thickness measurement, then device complexity is reduced, but measurement precision deteriorates due to improper alignment with anatomical features
Solution Approach 1:
The patent applies preliminary action by performing fundus image acquisition and anatomical landmark detection before the actual retinal thickness measurement. The system first captures the fundus image, identifies the fovea and optic disc locations, and then uses these detected positions to configure the measurement grid. This preliminary positioning ensures that the measurement grid is properly aligned with anatomical features before measurements are taken, improving alignment accuracy without requiring complex real-time adjustment mechanisms during measurement.
Solution Approach 2:
The patent introduces an intermediary computational layer that bridges the simple fixed grid concept and the need for precise anatomical alignment. The intermediary process involves detecting anatomical landmarks in fundus images and using these detections to transform and position the measurement grid appropriately. This intermediary step adds minimal complexity while significantly improving measurement precision by ensuring proper alignment with anatomical features.
3Reliability
If retinal thickness measurements are compared at different measurement loci, then ease of operation is improved by using standardized reference data, but reliability deteriorates due to errors in disease progression monitoring
Solution Approach 1:
The patent implements universality by creating a standardized measurement framework that can universally compare patient data with reference data from large populations. By defining specific measurement loci based on anatomical landmarks (such as the ETDRS grid positioned relative to the fovea and optic disc), the system enables consistent comparisons across different patients, instruments, and time points. This universal approach maintains reliability in disease progression monitoring while allowing the use of established reference datasets.
Solution Approach 2:
The patent applies copying by reproducing standardized measurement grids (such as the ETDRS grid) at the appropriate positions in each patient's retina based on their unique anatomical landmarks. Rather than requiring custom measurement schemes for each patient, the system copies the proven standardized grid design and positions it correctly using detected fovea and optic disc locations. This ensures that measurements are taken at corresponding anatomical locations across all patients, enabling reliable comparison with reference data while maintaining the simplicity of standardized protocols.
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 ensures precise mapping and comparison of retinal thickness measurements, improving diagnostic accuracy and disease monitoring by allowing proper alignment of patient data with reference data, even when anatomical features are not perfectly centered.
Implementation Method 1
Interferometric analysis of the back-reflected light yields information on the structure of the retina
Implementation Method 2
Part of the beam is back-reflected
Data Source
AI summary
Disclosed are method and apparatus for mapping retinal thickness values to a movable measurement grid. A three-dimensional volume dataset acquired from three-dimensional optical coherence tomography is registered to a fundus image by rendering a two-dimensional composite image from the three-dimensional volume dataset and superimposing characteristic features in the two-dimensional composite image upon corresponding characteristic features in the fundus image. A measurement grid is displayed on the two-dimensional composite image. The measurement grid is moved to a region of interest, and retinal thickness values in the region of interest are mapped to sectors within the measurement grid.