Astigmatism Axis Display Using Microscope Orientation Tracking

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Solution Overview

Problem

Existing methods for determining the astigmatism axis during eye surgery, such as manual, image processing, and measurement methods, suffer from inaccuracies due to visibility issues, reliance on prominent structures, and changes in the orientation of the operating microscope or surgical steps, leading to incorrect alignment of toric intraocular lenses.

Innovation Solution

A device and method using sensors, including rotation rate sensors and inertial measurement units, to track the orientation of the operating microscope and patient's head, calculating the current astigmatism axis by comparing it to a reference orientation, ensuring accurate display despite changes in the microscope's or patient's position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual marking methods are used to determine astigmatism axis orientation, then the procedure is simple to perform, but the accuracy and reliability of the measurement deteriorates due to manual errors and marking visibility issues

Engineering Contradiction:
Improvesimplicity of marking applicationVSAvoidaccuracy of astigmatism axis orientation
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces manual mechanical marking methods with an automated optical measurement system. The camera-based apparatus captures images of the eye and uses image processing algorithms to automatically determine the astigmatism axis orientation, eliminating manual marking errors and visibility issues while maintaining ease of operation through automated processing.

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

Solution Approach 2:

The patent creates a digital copy of the eye's surface features through camera imaging. By capturing and processing images of prominent structures (blood vessels, iris patterns), the system generates a digital representation that can be analyzed to determine astigmatism axis orientation without requiring physical markings on the eye.

Inventive Principle:
Principle #26Copying

2Extent of automation

If image processing methods using prominent structures are used to determine astigmatism axis, then automated measurement is achieved, but the reliability deteriorates when prominent structures are absent or obscured during surgery

Engineering Contradiction:
Improveautomated astigmatism axis determinationVSAvoidconsistency of measurement under varying surgical conditions
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

The patent implements a dynamic measurement system that continuously captures images during surgery and adapts to changing conditions. The system can identify and track prominent structures in real-time, and when structures become obscured due to bleeding or surgical intervention, the system can switch to alternative features or recalculate based on available data, maintaining reliability throughout the procedure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system incorporates feedback mechanisms where the camera continuously monitors the eye's surface, and the processing unit analyzes current images to determine if prominent structures are still visible and reliable for measurement. If structures are obscured, the system receives feedback about the degraded conditions and can adjust by using alternative features or alerting the surgeon, thereby maintaining measurement reliability.

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If the operating microscope orientation changes during surgery, then surgical flexibility is improved, but the accuracy of astigmatism axis display deteriorates due to orientation miscalculation

Engineering Contradiction:
Improvemicroscope repositioning freedomVSAvoidaccuracy of displayed astigmatism axis orientation
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent implements feedback through continuous tracking of the microscope's orientation using sensors (accelerometers, gyroscopes). The system constantly monitors changes in microscope position and angle, providing real-time feedback data to the processing unit. This allows the system to recalculate and adjust the displayed astigmatism axis orientation automatically, maintaining accuracy even as the surgeon repositions the microscope for different surgical angles.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system is designed to be dynamic rather than static, continuously updating the astigmatism axis display based on real-time microscope orientation data. As the microscope moves, the system dynamically recalculates the orientation parameters and adjusts the displayed information accordingly, ensuring that the astigmatism axis remains accurately represented regardless of microscope repositioning.

Inventive Principle:
Principle #15Dynamics

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

Provides robust and accurate real-time display of the astigmatism axis, unaffected by surgical interventions or microscope orientation changes, reducing latency and patient discomfort from prolonged illumination.

Implementation Method 1

The sensor device comprises at least one rotation rate sensor (20a) attached to the observation unit to detect a rotation angle of the observation unit about its observation direction

Methodology Applied
Scientific EffectRotation rate sensing: Gyroscope

Implementation Method 2

using sensors, including rotation rate sensors and inertial measurement units, to track the orientation of the operating microscope and patient's head

Methodology Applied
Scientific EffectInertial measurement: Accelerometer

Data Source

PatentEP3518733B1Device and method for displaying the axis of astigmatism of an eye
Publication Date: 2026.04.01 CHRONOS VISION
  • EP3518733B1 patent drawingFigure 1
  • EP3518733B1 patent drawingFigure 2~3A
  • EP3518733B1 patent drawingFigure 3B~3C

AI summary

The invention relates to a device and a method for displaying the axis of astigmatism of an eye, in which an observation unit (10) is used to observe the eye (13) and, using a display unit (11), the orientation R of the axis of astigmatism of the eye (13) is displayed. A sensor unit (20, 20a, 21, 22, 23) generates sensor data which indicate a modification to the alignment of the observation unit (10) relative to the eye (13). A calculation unit (30) updates the displayed orientation of the axis of astigmatism with the aid of the sensor data, and issues it as the current orientation R' of the display unit (30).