Ophthalmological Device Quality Verification

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing ophthalmological examination devices face challenges in achieving precise and reproducible measurements due to time-consuming distance determination, mechanical effort, and potential interference from eyelashes or an insufficient tear film, leading to incorrect results under unfavorable conditions.

Innovation Solution

An ophthalmological measuring device with connected evaluation units that assess quality parameters through multiple successive measurements, generating signals (visual, acoustic, or tactile) to indicate suitable measurement conditions, allowing the operator to trigger the final measurement only when criteria are met.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the measurement distance is determined by pivoting the collimator lens between finite and infinite positions, then the measurement distance can be determined, but the process becomes time-consuming and requires additional mechanical effort

Engineering Contradiction:
Improvemeasurement distance determinationVSAvoidtime for distance determination
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent removes the collimator lens pivoting mechanism entirely. Instead of mechanically moving the lens between finite and infinite positions, the system uses a fixed projection optical system that projects marks from both finite and infinite positions simultaneously onto the cornea. This extracts the problematic mechanical movement while retaining the functional benefit of dual-position measurement capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical pivoting system with an optical solution. A single fixed projection optical system uses optical paths to achieve what previously required mechanical movement. The system projects marks from finite and infinite positions simultaneously without any mechanical movement of the projection system, substituting mechanical action with optical field manipulation.

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

2Productivity

If automatic measurement triggering is implemented, then measurement efficiency is improved, but measurements may be taken under unsuitable conditions leading to incorrect results

Engineering Contradiction:
Improvemeasurement efficiencyVSAvoidmeasurement accuracy under unfavorable conditions
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent introduces a quality assessment system that provides feedback before automatic triggering. The evaluation unit analyzes images captured during the measurement process and assesses quality parameters such as corneal reflection clarity, mark visibility, and optical path quality. Only when quality thresholds are met does the system generate the triggering signal, ensuring measurements are taken only under suitable conditions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary quality assessment before the actual measurement is triggered. The system captures preliminary images, evaluates their quality, and determines whether conditions are suitable for measurement before committing to the measurement process. This preliminary action prevents wasted measurements under unfavorable conditions while maintaining high efficiency when conditions are good.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If multiple measuring systems are used to take several measurements, then measurement reliability can be improved, but the complexity of the device increases

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple measurement functions into a single integrated measuring device. The projection optical system projects marks for both keratometry (corneal curvature) and anterior chamber depth measurement simultaneously. The same image capture system and evaluation unit handle both measurement types, merging multiple measuring systems into one cohesive device that achieves high reliability without proportional increases in complexity.

Inventive Principle:
Principle #5Merging (Combining)

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

Ensures precise and reliable measurement results by verifying measurement quality before triggering, reducing errors caused by unsuitable conditions and mechanical complexities.

Implementation Method 1

The light reflected by the cornea is imaged on a CCD camera and the corneal radii are calculated from the distance between the punctiform reflection images

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP2091408B1Ophthalmological examination device
Publication Date: 2017.04.26 CARL ZEISS MEDITEC AG
  • EP2091408B1 patent drawingFigure 1~2

AI summary

The invention relates to an ophthalmological measuring instrument, e.g. for determining the corneal curvature, anterior chamber depth, axial length, or the like, comprising measuring systems for determining said variables. The measuring systems are connected to an evaluation unit which verifies whether quality parameters regarding the measurements are satisfied and generates a corresponding signal that indicates to the user that a proper measurement can be taken.