Viscoelastic Soft Tip Plunger for Intraocular Lens Delivery

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Solution Overview

Problem

Existing soft tip plungers used in intraocular lens (IOL) insertion tools can cause sudden or self-ejection of the IOL due to rapid expansion and release of stored spring energy after compression, leading to undesirable complications during eye surgery.

Innovation Solution

The use of a plunger with a viscoelastic soft tip that has a specific durometer value and viscoelastic properties, including a storage modulus of 10 MPa to 50 MPa and a loss modulus of 50 MPa to 300 MPa, to engage and deliver the IOL through the nozzle, thereby reducing the sudden release of spring energy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a soft tip plunger is used to deliver the IOL, then the IOL is protected from damage during insertion, but the soft tip compresses and stores spring energy which is then rapidly released causing sudden or self-ejection of the IOL

Engineering Contradiction:
Improvedamage to IOLVSAvoidcontrolled delivery of IOL
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies parameter changes by specifying precise viscoelastic properties (storage modulus: 10-50 MPa, loss modulus: 50-300 MPa) and durometer value (20-50 D) for the soft tip material. These controlled material parameters ensure the tip provides sufficient softness to protect the IOL while having controlled elastic recovery to prevent sudden expansion and self-ejection.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The plunger employs a composite structure combining a rigid shaft portion with a viscoelastic soft tip made from specialized materials (such as silicone rubber or polyurethane). This composite design allows the rigid shaft to deliver force effectively while the viscoelastic tip provides cushioning and controlled deformation during IOL delivery.

Inventive Principle:
Principle #40Composite materials

2Force

If the soft tip is made softer to protect the IOL, then more force can be applied without damaging the lens, but the spring energy storage and rapid expansion increases causing more violent ejection

Engineering Contradiction:
Improveforce applied to IOLVSAvoidspring energy release
Core Design Contradiction:
ForceVSObject-generated harmful factors

Solution Approach 1:

The patent resolves this contradiction by precisely controlling the viscoelastic parameters of the soft tip material. The storage modulus (10-50 MPa) provides sufficient elasticity to protect the IOL during force application, while the loss modulus (50-300 MPa) ensures controlled energy dissipation during expansion, preventing violent spring-back effects.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The soft tip exhibits dynamic viscoelastic behavior that adapts to the delivery process. During compression, the tip deforms to protect the IOL; during expansion, the controlled viscoelastic recovery prevents sudden energy release. The material's time-dependent mechanical properties allow it to absorb and dissipate energy in a controlled manner throughout the delivery cycle.

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

The viscoelastic soft tip effectively reduces the tendency for sudden or self-ejection of the IOL, ensuring a controlled delivery and minimizing complications during IOL insertion.

Implementation Method 1

the plunger comprises an elongated portion and a viscoelastic soft tip at a distal end of the elongated portion, wherein the viscoelastic soft tip has a durometer value of about 20 00 to about 50 D on the Shore hardness scale, wherein the viscoelastic soft tip has a storage modulus of about 10 megapascal to about 50 megapascals, and wherein the viscoelastic soft tip has a loss modulus of about 50 megapascal to about 300 megapascals

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Data Source

PatentEP3996628B1Viscoelastic soft tip plunger
Publication Date: 2025.06.04 ALCON INC
  • EP3996628B1 patent drawingFigure 1
  • EP3996628B1 patent drawingFigure 2~3
  • EP3996628B1 patent drawingFigure 4

AI summary

Systems, methods, and devices for inserting an intraocular lens (IOL) assembly into an eye may be provided. An apparatus for delivery of a lens component into an eye may include a housing. The apparatus may further include a plunger at least partially disposed in the housing, wherein the housing comprises an elongated portion and a viscoelastic soft tip at a distal end of the elongated portion, wherein the viscoelastic soft tip has a storage modulus of about 1 megapascal (MPa) to about 300 MPa and a loss module of about 1 MPa to about 300 MPa. The apparatus may further include a drive mechanism operatively coupled to plunger and configured to cause the plunger to translate in the housing. The apparatus may further include a nozzle operatively coupled to the housing through which the plunger delivers the lens component into the eye.