Automated Optic Nerve Head Analysis via 3D OCT Minimum Area Surface

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Solution Overview

Problem

Current methods for analyzing the optic nerve head (ONH) are subjective, variable, and lack repeatable, anatomically relevant definitions of the optic disc and cup margins, hindering accurate structural measurements and disease management in optic neuropathies like glaucoma.

Innovation Solution

A fully automated method using 3D OCT data to define the optic disc margin based on the minimum area surface between the optic disc margin and the vitreoretinal interface, calculating the neuroretinal rim area by summing sector or vector-based cross-sectional areas, and providing unambiguous, clinically meaningful measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual estimation of optic disc and cup margins is performed by expert clinicians, then diagnostic experience and anatomical knowledge can be applied, but the method remains subjective and variable with poor repeatability

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidrepeatability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the manual mechanical estimation process with an automated image processing system that uses digital image analysis algorithms to objectively define optic disc and cup margins, eliminating human subjectivity while maintaining diagnostic accuracy

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system enables self-service automation where the imaging system automatically performs margin detection and measurement without requiring manual clinician intervention, achieving consistent and repeatable results through standardized computational algorithms

Inventive Principle:

Principle #25Self-service

2Reliability

If automated image processing is implemented to remove subjectivity, then measurement repeatability improves, but the method may lose the benefit of expert clinical judgment and anatomical knowledge

Engineering Contradiction:

ImproverepeatabilityVSAvoidmeasurement accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent introduces an intermediary layer of automated image processing that bridges expert clinical knowledge and objective measurement by encoding anatomical rules and diagnostic criteria into computational algorithms, preserving expert judgment while achieving automation

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system transforms subjective visual assessment parameters into objective digital measurements by converting anatomical landmarks and boundary definitions into quantifiable image processing parameters that can be consistently measured and compared

Inventive Principle:

Principle #35Parameter changes

3Extent of automation

If the optic cup margin is defined using fixed offset from disc reference plane, then automated measurement becomes feasible, but the definition becomes arbitrary and loses anatomical meaning

Engineering Contradiction:

Improveautomation capabilityVSAvoidanatomical relevance

Core Design Contradiction:

Extent of automationVSMeasurement precision

Solution Approach 1:

Instead of defining the cup margin by a fixed offset from the disc plane, the patent inverts the approach by defining it through the actual anatomical termination of the retinal pigment epithelium, using the natural tissue boundary rather than an arbitrary geometric construct

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The system segments the optic nerve head structure into distinct anatomical layers and components, identifying the retinal pigment epithelium termination as a separate detectable feature that naturally defines the cup margin without requiring arbitrary offset measurements

Inventive Principle:

Principle #1Segmentation

4Difficulty of detecting and measuring

If disc margin is difficult to see in fundus images due to poor image quality or obscuring anatomy, then manual measurement becomes unreliable, but automated systems may fail to detect the margin

Engineering Contradiction:

Improvemargin visibilityVSAvoidmeasurement consistency

Core Design Contradiction:

Difficulty of detecting and measuringVSReliability

Solution Approach 1:

The patent transitions from two-dimensional fundus image analysis to three-dimensional optical coherence tomography imaging, adding the depth dimension that allows visualization of the retinal pigment epithelium termination and other structural features that define the disc and cup margins, making them visible even when obscured in conventional images

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS9918680B2Automated analysis of the optic nerve head via optical coherence tomography measurements, methods and representations

Publication Date: 2018.03.20 CARL ZEISS MEDITEC INC

AI summary

The present invention relates to structural analysis of the optic nerve head (ONH). In one approach, a 3D volume of intensity data which includes the optic nerve head is acquired using an optical coherence tomography (OCT) system. The vitreoretinal interface (VRI) and the optic disc margin are identified from the 3D data. The minimum area of a surface from the optic disc margin to the VRI is determined. This minimum area can be displayed as an image or in the alternative, a value corresponding to this minimum area can be displayed. The minimum area measurement provides relevant clinical information to determine the health of the eye.