Intraocular Lens Haptic Joint Mechanism for Rotational Stability

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Solution Overview

Problem

Existing intraocular lenses lack sufficient rotational stability, particularly for toric lenses, which can lead to imaging errors if incorrectly oriented in the capsular bag during cataract treatment.

Innovation Solution

The intraocular lens features a haptic with a joint mechanism and a support projection that provides restoring force, allowing the lens to maintain high rotational stability by adjusting to the size of the capsular bag, with features such as film joints and varying stiffness to ensure proper positioning and fixation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional haptic design is used, then the lens can be inserted into the capsular bag, but rotational stability is insufficient leading to imaging errors

Engineering Contradiction:
Improverotational stabilityVSAvoidhaptic structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The haptic is divided into multiple segments (first arm, second arm, third arm) connected by joints (first joint, second joint, third joint). This segmentation allows each segment to move independently, enabling the haptic to adapt to the capsular bag while maintaining rotational stability through the coordinated movement of segmented components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The haptic employs a dynamic joint mechanism that allows movement and adaptation rather than being rigid. The joints enable the haptic to dynamically adjust its configuration in response to forces from the capsular bag, maintaining optimal positioning and rotational stability through controlled motion rather than rigid fixation.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If the haptic is made more rigid to improve positioning stability, then positioning accuracy improves, but the lens cannot adapt to varying capsular bag sizes

Engineering Contradiction:
Improvepositioning accuracyVSAvoidadaptability to capsular bag size
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The joint mechanism provides dynamic adaptation capability, allowing the haptic to change its configuration based on capsular bag size while maintaining precise positioning. The joints act as flexible connection points that accommodate size variations without compromising the accuracy of lens placement within the capsular bag.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The haptic's effective length and configuration can change through joint movement in response to capsular bag size variations. This parameter change allows the same haptic structure to adapt to different capsular bag dimensions while maintaining optimal positioning accuracy through the restored force mechanism.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the first arm is made longer to increase contact surface with capsular bag, then rotational stability improves, but the joint mechanism complexity increases

Engineering Contradiction:
Improverotational stabilityVSAvoidjoint mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The first arm is segmented into multiple sections connected by joints, which distributes the complexity across multiple simple joint mechanisms rather than requiring a single complex structure. This segmentation allows the arm to achieve sufficient contact surface area while maintaining manageable complexity through modular joint design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The joint mechanism merges the functions of positioning, adaptation, and stabilization into a single integrated system. The first joint, second joint, and third joint work together as a unified mechanism that provides rotational stability through coordinated movement of the first arm, second arm, and third arm, reducing overall system complexity compared to separate mechanisms.

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

The design enhances rotational stability, ensuring accurate image formation on the retina by maintaining the lens's optimal orientation, even with varying capsular bag sizes, thereby reducing imaging errors.

Implementation Method 1

at least one of the second joint, the third joint and the fourth joint is arranged, a to exert restoring force when the joint gear is moved out of its rest position

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3747402B1Intraocular lens
Publication Date: 2023.12.20 CARL ZEISS MEDITEC AG
  • EP3747402B1 patent drawingFigure 1~2
  • EP3747402B1 patent drawingFigure 3~4

AI summary

The invention relates to an intraocular lens (1) with an optical body (2) and a haptic (3) comprising a joint mechanism (20) comprising a first arm (5a) forming the radially outer part of the haptic (3) and a first longitudinal end (11) and a second longitudinal end (12), a first joint (6a) arranged at a position between the first longitudinal end (11) of the first arm (5a) and the second longitudinal end (12) of the first arm (5a) and by means of which the first arm (5a) is pivotably coupled to the optical body (2), a second arm (5b), a third arm (5c), a second joint (6b), a third joint (6c) and a fourth joint (6d), wherein the second joint (6b) is arranged at the second longitudinal end (12) of the first arm (5a) and at a first longitudinal end (14) of the second arm (5b) and the first arm (5a) pivotable with the second arm (5b) coupled,the third joint (6c) is arranged at a second longitudinal end (15) of the second arm (5b) and at a first longitudinal end (16) of the third arm (5c) and pivotably couples the second arm (5b) to the third arm (5c), the fourth joint (6d) is arranged at a second longitudinal end (17) of the third arm (5c) and pivotably couples the third arm (5c) to the optical body (2), and at least one of the second joint (6b), the third joint (6c), and the fourth joint (6d) is configured to exert a restoring force when the joint mechanism (20) is moved from its rest position.