Negative Pressure Fixation Perimeter for Objective Visual Field Testing

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Solution Overview

Problem

Current computer-automated perimeters face challenges in accurately measuring the field of view due to fixation point deviations and patient subjectivity, leading to issues with repeatability, specificity, sensitivity, and accuracy in detecting early ocular diseases.

Innovation Solution

A perimeter system that includes a fixation forcing device using negative pressure to maintain eye fixation, combined with an electro-physiological objective perimeter, which uses light guide fibers and an electro-physiological examination instrument to record feedback and eliminate the influence of fixation points, allowing for precise and objective measurement of the field of view.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional computer automated perimetry is used, then the examination can be completed with standard equipment, but the accuracy and repeatability are reduced due to fixation point deviations and patient subjectivity

Engineering Contradiction:
Improvefield of view measurement accuracyVSAvoidrepeatability of examination results
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the subjective mechanical response system (patient pressing buttons) with an objective electro-physiological detection system. The electro-physiological examination instrument detects electrical signals from the retina in response to light stimulation, eliminating the need for patient subjective response and button-pressing actions, thereby resolving the contradiction between measurement precision and reliability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary fixation forcing device that applies negative pressure to the eyeball to maintain stable fixation. This intermediary mechanism mediates between the light stimulation system and the electro-physiological detection system, ensuring stable eye position and eliminating fixation deviations that would otherwise compromise measurement accuracy and repeatability

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If fixation forcing device with negative pressure is used, then eye position stability is improved, but device complexity increases

Engineering Contradiction:
Improveeye position stabilityVSAvoidperimeter system complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent merges the fixation forcing device with the existing perimeter system by integrating the negative pressure application mechanism into the examination apparatus. The fixation forcing device is combined with the light guide fibers and electro-physiological examination instrument, creating a unified system that maintains eye stability without requiring separate independent equipment, thereby limiting the increase in device complexity

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If electro-physiological objective perimeter is used, then patient subjectivity is eliminated, but the system requires complex electro-physiological examination instrumentation

Engineering Contradiction:
Improveobjectivity of measurementVSAvoidexamination instrument complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses light guide fibers as an intermediary to transmit light stimulation from the perimetry display device to the patient's retina, and to conduct the electro-physiological signals back to the examination instrument. This intermediary optical transmission system simplifies the connection between the display device and the electro-physiological detection system, reducing the overall system complexity while maintaining measurement objectivity

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The system significantly improves the accuracy and repeatability of perimetry results by maintaining consistent eye position relative to the perimetry display, reducing subjective influences, and enabling objective electro-physiological analysis for enhanced disease detection.

Implementation Method 1

The fixation forcing device is adsorbed to the eyeball of a testee by negative pressure

Methodology Applied
Scientific EffectNegative pressure: Pressure Gradient

Implementation Method 2

the display conduction device comprises light guide fibers connected to the fixation forcing device and the perimetry display device respectively

Methodology Applied
Scientific EffectLight guide: Optical Fibre

Implementation Method 3

the feedback device is an electro-physiological examination instrument for examining a field of view of a testee

Methodology Applied
Scientific EffectElectro-physiological signal detection: Photoelectric Effect

Data Source

PatentEP3620102B1perimeter
Publication Date: 2024.10.09 LIN CHEN
  • EP3620102B1 patent drawingFigure 1~2
  • EP3620102B1 patent drawingFigure 3~4

AI summary

A perimeter, including two types: one is a fixation forcing perimeter, and the other is an objective perimeter combined with electro-physiology under forced fixation; the perimeter comprises a fixation forcing device, a display conduction device, a perimetry display device, a feedback device for recording feedback information, and a control center for controlling the perimetry display device and collecting feedback information; the fixation forcing device comprises a negative pressure ring (2) and a negative pressure tube (3), and is adsorbed to the eyeball by negative pressure; when the eyeball moves, the fixation forcing device moves synchronously, and the fixation is forced at the same position, thereby eliminating the influence of a fixation point on the examination results of the perimeter; in the objective perimeter, an electro-physiological signal after forced fixation is automatically recorded by an electro-physiological instrument, so that the subjective response of a patient is eliminated, and the examination results are objective; and the change in the field of view can be early discovered using the electro-physiological signal as an analysis indicator.