Retinal Layer Thickness Measurement at Visual Field Stimulation Points

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Solution Overview

Problem

Current ophthalmologic examination technologies cannot effectively correlate visual field abnormalities with morphological abnormalities of the retina, particularly in visual-field examinations, as they lack the capability to measure retina layer thickness at specific stimulation points.

Innovation Solution

An ophthalmologic information-processing apparatus that accepts 3D images of the retina, specifies positions corresponding to stimulation points, and analyzes these images to determine layer thickness, including identifying positions where ganglion cells receive signals from cone cells, enabling correlation between visual field functions and retina morphology.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If visual field examination is performed using conventional perimeter, then visual field sensitivity can be measured, but it is impossible to grasp morphological abnormalities of the retina at corresponding stimulation points

Engineering Contradiction:
Improveretina morphology informationVSAvoidexamination system complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent merges visual field examination functionality with OCT imaging capability into a single integrated system. The perimeter and OCT apparatus are combined so that retinal morphology can be measured at the same stimulation points where visual field sensitivity is tested, eliminating the need for separate examinations and enabling direct correlation between functional and structural data.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The examination apparatus is designed with multi-functionality, serving both as a visual field perimeter and an OCT imaging device. This universal system can perform both functional visual field measurement and structural retinal imaging through the same optical path and positioning mechanism, allowing a single device to provide comprehensive diagnostic information.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Loss of information

If separate examinations for visual field and retinal morphology are conducted, then each can be measured independently, but correlation between visual field abnormalities and retinal morphology cannot be established

Engineering Contradiction:
Improvecorrelation informationVSAvoidexamination time
Core Design Contradiction:
Loss of informationVSLoss of time

Solution Approach 1:

The patent combines visual field examination and OCT imaging into a single integrated process where both measurements are performed simultaneously or in sequence using the same positioning reference. This merging eliminates the time required for separate examinations while establishing direct spatial correlation between visual field sensitivity data and retinal morphology at corresponding locations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces an intermediary coordination mechanism that links the visual field stimulation point positioning with the OCT imaging positioning. This intermediary system ensures that the retinal location imaged corresponds precisely to the stimulation point being tested, enabling accurate correlation between functional and structural findings without requiring separate examination procedures.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If conventional OCT imaging is used, then retinal morphology can be visualized, but measurement at specific visual field stimulation points is not possible

Engineering Contradiction:
Improveretina layer thickness measurement precisionVSAvoidexamination adaptability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The OCT apparatus is designed with universal positioning capability that allows it to acquire retinal images at specific locations corresponding to visual field stimulation points. The system can adapt its imaging position based on the stimulation point coordinates, enabling both high-precision measurement at targeted locations and flexible adaptation to different examination requirements.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system implements local quality measurement by focusing OCT imaging resources on specific retinal regions corresponding to visual field stimulation points. Rather than uniformly imaging the entire retina, the apparatus concentrates measurement precision at the locally relevant areas that correspond to the functional test locations, optimizing both precision and adaptability.

Inventive Principle:
Principle #3Local quality

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

Enables accurate measurement of retina layer thickness at stimulation points, allowing for a clear correlation between visual field functions and retina morphology, thereby diagnosing abnormalities effectively.

Implementation Method 1

The OCT technology is a technology of using optical beams to form images that represent the surface morphology or the internal morphology of an object to be measured

Methodology Applied
Scientific EffectOptical Coherence Tomography (OCT):

Implementation Method 2

obtains the spectral intensity distribution of the reflected light, and performs Fourier transform thereof, thereby converting the morphology of the object to be measured in the depth direction (z direction) into an image

Methodology Applied
Scientific EffectFourier transform:

Implementation Method 3

a measuring arm scans an object by using a rotating mirror (Galvano mirror)

Methodology Applied
Scientific EffectGalvano mirror scanning:

Implementation Method 4

an interference device, in which the intensity of lights emerging from the interference of light fluxes from the measuring arm and the reference arm is also analyzed by a spectroscope

Methodology Applied
Scientific EffectLight interference: Interference

Data Source

PatentEP2022391B1Ophthalmologic information-processing apparatus and ophthalmologic examination apparatus
Publication Date: 2010.05.12 TOPCON CORPORATION
  • EP2022391B1 patent drawingFigure 1
  • EP2022391B1 patent drawingFigure 2
  • EP2022391B1 patent drawingFigure 3

AI summary

An ophthalmologic examination apparatus 1 projects a light onto a fundus oculi, detects the reflected light thereof, and forms a 3-dimensional image that represents the morphology of a retina based on the detected results. A stimulation-position specifying part 233 specifies, in the 3-dimensional image, a plurality of stimulation positions that correspond to a plurality of stimulation points Pi in a visual-field examination. A layer-thickness measuring part 235 analyzes the 3-dimensional image to find the layer thickness of the retina at each stimulation position. In addition, a displacement calculation part 234 specifies a related position of the stimulation position. A layer-thickness measuring part 235 finds the layer thickness of the retina at the related position.