Visual Acuity Prediction from Wavefront Aberration Data

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Solution Overview

Problem

Current methods for determining visual acuity from wavefront information of the eye do not provide a direct value for visual acuity, despite measuring wavefront aberrations and point spread functions, leaving a gap in objective measurement.

Innovation Solution

The method involves analyzing the point spread function by comparing intensities to determine relevant areas, fitting an ellipse around these areas to derive image quality metrics, and using the ratio of the ellipse's axes to calculate visual acuity, considering pupil diameter and accommodation states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If wavefront aberration measurement and point spread function analysis are performed, then image quality assessment is improved, but direct visual acuity determination is not achieved

Engineering Contradiction:
Improveimage quality assessmentVSAvoidvisual acuity value
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent introduces an intermediary calculation process that transforms wavefront aberration data and point spread function analysis into a predicted visual acuity value. The intermediary element is the computational algorithm that processes the measured optical parameters and converts them into a clinically meaningful visual acuity prediction, bridging the gap between optical measurement and functional vision assessment.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces traditional subjective visual acuity measurement methods (mechanical/optical testing charts requiring patient response) with a computational approach. By substituting the mechanical testing system with an optical measurement and calculation system, the patent objectively determines visual acuity from wavefront data without requiring patient participation in traditional acuity testing.

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

2Loss of information

If multiple image quality metrics are calculated from point spread function, then image quality characterization is improved, but direct correlation with visual acuity is lost

Engineering Contradiction:
Improveimage quality characterizationVSAvoidvisual acuity correlation
Core Design Contradiction:
Loss of informationVSMeasurement precision

Solution Approach 1:

The patent transforms multiple image quality parameters (encircled energy, Strehl ratio, full width at half maximum) into a single predicted visual acuity parameter through a computational model. By changing the parameter representation from multiple optical metrics to a single functional vision metric, the patent establishes direct correlation with visual acuity while preserving the information contained in the multiple image quality characteristics.

Inventive Principle:
Principle #35Parameter changes

3Extent of automation

If visual acuity is determined objectively from wavefront data, then measurement objectivity is improved, but adaptation to varying pupil sizes and accommodation states requires complexity

Engineering Contradiction:
Improveobjective measurementVSAvoidaccommodation state consideration
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The patent creates a universal calculation method that handles multiple conditions (different pupil diameters, various accommodation states) through a single integrated algorithm. The system performs multiple functions by processing wavefront data to predict visual acuity across different viewing conditions without requiring separate measurement systems or procedures for each condition.

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

Data Source

PatentUS7654674B2Method and apparatus for determining the visual acuity of an eye
Publication Date: 2010.02.02 BAUSCH & LOMB INC
  • US7654674B2 patent drawing
  • US7654674B2 patent drawing
  • US7654674B2 patent drawing

AI summary

The invention relates to a method for determining the visual acuity of an eye and a respective apparatus. The method comprises the steps of: providing the wavefront information of the eye, generating a point spread function based on the wavefront information of the eye, said point spread function representing a specific intensity distribution for a corresponding pupil size. After comparing the intensities of the point spread function with a selectable intensity level of intensity, those parts of the point spread function having an intensity being larger than the selectable intensity level are determined as a relevant part of the point spread function.