Myopia Control Lens With Compound Power Profile

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Solution Overview

Problem

Current contact lens designs are inadequate for preventing or slowing the progression of myopia, particularly in individuals with early stages of myopia, as they either fail to address peripheral hyperopic stimulus or cause excessive peripheral myopic defocus that can accelerate myopia progression.

Innovation Solution

A contact lens with a power profile defined by a compound mathematical function that creates both on-axis and off-axis myopic defocus, providing increased positive power for central and peripheral light rays to reduce on-axis and off-axis hyperopic defocus, thereby slowing eye growth without degrading central vision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a lens provides on-axis myopic defocus to remove hyperopic defocus, then myopia progression is reduced, but peripheral hyperopic stimulus remains unaddressed and can accelerate myopia progression

Engineering Contradiction:
Improvemyopia progression controlVSAvoidperipheral vision correction
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The lens applies different optical powers to different regions: the central region provides myopic defocus to counteract hyperopic stimulus, while the peripheral region provides hyperopic defocus to address peripheral hyperopic stimulus. This spatial differentiation of optical properties resolves the contradiction between central and peripheral vision correction needs.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The lens is divided into distinct functional zones with different optical characteristics. The central optical zone and peripheral carrier zone are segmented to provide different defocus effects, allowing simultaneous addressing of both on-axis and off-axis hyperopic stimuli that drive myopia progression.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If a lens provides excessive peripheral myopic defocus to address peripheral hyperopia, then peripheral vision is improved, but myopia progression is accelerated

Engineering Contradiction:
Improveperipheral vision correctionVSAvoidmyopia progression control
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The lens applies hyperopic defocus specifically to the peripheral regions rather than uniform myopic defocus across the entire lens. This localized application of hyperopic power in the peripheral carrier zone corrects peripheral hyperopic stimulus without creating excessive peripheral myopic defocus that would accelerate myopia progression.

Inventive Principle:
Principle #3Local quality

3Reliability

If a lens increases positive power for central and peripheral light rays to create myopic defocus, then on-axis and off-axis hyperopic defocus are reduced, but central vision quality may be degraded

Engineering Contradiction:
Improvehyperopic defocus reductionVSAvoidcentral vision acuity
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The lens applies myopic defocus partially and selectively in the central optical zone rather than uniformly across the entire lens. By limiting the strength and spatial extent of myopic power increase, the lens reduces hyperopic defocus sufficiently to slow myopia progression while maintaining central vision quality within acceptable limits.

Inventive Principle:
Principle #16Partial or excessive action

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 lens effectively prevents or slows the progression of myopia by reducing hyperopic defocus without causing perceptible degradation in central vision, as demonstrated by experiments comparing different lens designs.

Implementation Method 1

The lens has a power profile that creates on-axis and off-axis myopic defocus... The profile creates the on-axis and off-axis myopic defocus by providing an increase in positive (plus) power for central and peripheral light rays that pass through the central vision and peripheral regions, respectively

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP2321690B1A lens design and method for preventing or slowing the progression of myopia
Publication Date: 2020.05.27 ALCON INC
  • EP2321690B1 patent drawingFigure 1
  • EP2321690B1 patent drawingFigure 2
  • EP2321690B1 patent drawingFigure 3

AI summary

A lens is provided that is capable of preventing or slowing the progression of myopia when worn by a person. The lens has a power profile that reduces on-axis and off-axis hyperopic defocus created by the optics of the eye by creating on-axis and off-axis myopic defocus. The on-axis and off-axis myopic defocus is created by providing light rays that pass through a central vision region of the optical portion and light rays that pass through a peripheral region of the optical portion an increase in positive (plus) power. The overall effect is to prevent or slow the progression of myopia without any perceptible degradation in the person's central vision.