Non-Telecentric Fixation Target for Eye Accommodation Relaxation

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Solution Overview

Problem

Conventional autorefractors and aberrometers are not completely reliable in fully relaxing the accommodation of a significant percentage of patients' eyes during refraction measurements, leading to erroneous or inaccurate results, which lacks confidence in prescriptions based solely on autorefractions.

Innovation Solution

A fixation target system with a movable stage configuration, including a wavefront aberrometer and Shack-Hartmann wavefront sensor, uses non-telecentric projection of a fixation target to effectively relax the eye's accommodation by moving the target away from the eye, ensuring consistent blur cues and a decreasing image size on the retina, thereby improving accommodation relaxation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixation target is used to relax accommodation during refraction measurement, then the eye's accommodation should be fully relaxed, but about ten percent of people do not fully relax accommodation resulting in measurement errors

Engineering Contradiction:

Improvereliability of accommodation relaxationVSAvoidaccuracy of refraction measurement

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent employs dynamic control of the fixation target's position and optical characteristics through movable stages. The target can be moved along the optical axis and laterally, and its optical properties can be dynamically adjusted during measurement to ensure consistent blur cues that promote complete accommodation relaxation across different patient types.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes key parameters of the fixation target system including its position (axial and lateral), optical magnification, and blur characteristics. By dynamically adjusting these parameters, the system adapts to different patient responses and ensures optimal accommodation relaxation conditions are maintained throughout the measurement process.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If conventional telecentric projection is used, then the image size on the retina remains constant, but this provides inconsistent blur cues that prevent full accommodation relaxation in some patients

Engineering Contradiction:

Improveconstant image size on retinaVSAvoidaccommodation relaxation effectiveness

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent inverts the conventional telecentric approach by using non-telecentric projection. Instead of maintaining constant image size, the system allows the image size to change in a controlled manner that provides consistent blur cues. This inversion of the traditional approach creates the desired accommodation relaxation effect in patients who fail with conventional methods.

Inventive Principle:

Principle #13The other way round (Inversion)

3Reliability

If the fixation target is moved away from the eye to relax accommodation, then accommodation relaxation improves, but the image size on the retina changes which may confuse blur cues

Engineering Contradiction:

Improveaccommodation relaxationVSAvoidconsistency of blur cues

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The patent incorporates feedback mechanisms that monitor the patient's accommodation state and the optical characteristics of the fixation target. Based on this feedback, the system dynamically adjusts target position and optical parameters to maintain consistent blur cues while ensuring accommodation relaxation occurs. This closed-loop control prevents the loss of information about cue consistency.

Inventive Principle:

Principle #23Feedback

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

This approach enhances the reliability of refraction measurements by achieving fully relaxed accommodation in a larger percentage of patients, reducing errors and increasing confidence in prescription accuracy.

Implementation Method 1

an optical system disposed in an optical path between the fixation target and the eye, wherein the optical system is configured for non-telecentric projection of the fixation target upon the eye

Methodology Applied

Scientific EffectNon-telecentric projection: Lens

Implementation Method 2

a wavefront aberrometer configured to measure a refraction of an eye

Methodology Applied

Scientific EffectWavefront sensing: Refraction

Implementation Method 3

wavefront aberrometer and Shack-Hartmann wavefront sensor

Methodology Applied

Scientific EffectShack-Hartmann effect:

Data Source

PatentUS11896306B2Optical measurement systems and processes with non-telecentric projection of fixation target to eye

Publication Date: 2024.02.13 AMO DEVELOPMENT LLC

AI summary

A system includes: a first movable stage which is movable with respect to an eye of a subject; a second movable stage mounted on the first movable stage, wherein the second movable stage is movable with respect to the first movable stage; a fixation target disposed on the second movable stage; and an optical system disposed in an optical path between the fixation target and the eye, wherein the optical system is configured for projecting the fixation target upon the eye to accommodate the eye, and wherein moving the second movable stage to a position where the fixation target is moved away from the eye by an additional amount causes blur cues of the fixation target to indicate to the subject that the fixation target is moving away from the eye while the size of an image of the fixation target on the retina of the eye decreases.