Segmented Haptics for Accommodative Intraocular Lens Stability
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Solution Overview
Problem
Conventional intraocular lenses (IOLs) fail to provide sufficient accommodation for near vision due to the loss of elasticity in the capsular bag following cataract surgery, leading to limited axial displacement and movement of the lens, which is further constrained by capsular fibrosis.
Innovation Solution
A flexible optic holder with regularly-spaced zonular capture haptics that allow fusion of the capsular bag and subsequent sectioning to restore elasticity, enabling independent movement of haptics in response to ciliary muscle and zonular forces, thereby enhancing accommodative amplitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional IOLs are implanted in the capsular bag, then the lens is secured in place, but the loss of elasticity in the fibrotic capsule constrains axial displacement and reduces accommodation
Solution Approach 1:
The haptic is divided into multiple segments (first haptic segment, second haptic segment, third haptic segment) that can move independently relative to each other. This segmentation allows the haptic to navigate through the fibrotic capsule while maintaining lens stability, as each segment can adapt to the constrained environment separately rather than as a single rigid structure.
Solution Approach 2:
The haptic is designed with dynamic characteristics, being flexible and capable of bending and moving in response to capsular forces. The haptic's ability to change its configuration dynamically allows it to maintain lens positioning while accommodating the reduced elasticity of the fibrotic capsule, enabling axial displacement despite capsule rigidity.
2Stability of the object's composition
If the capsular bag is allowed to fuse and form a rigid capsular disc, then healing is achieved, but elasticity is lost and accommodation amplitude decreases
Solution Approach 1:
The haptic interacts with different regions of the capsular bag locally, with each haptic segment engaging with the capsule at specific locations. This local interaction allows the haptic to maintain lens stability in the fused capsular disc while still enabling movement through localized deformation and bending of the haptic segments.
Solution Approach 2:
The haptic's physical parameters (flexibility, bending radius, segment length) are specifically designed to change in response to the capsular environment. The haptic can alter its effective stiffness and configuration to adapt to the fibrotic capsule's reduced elasticity, maintaining both stability and movement capability.
3Reliability
If haptics are used to secure the IOL in the capsular bag, then the lens is held in place, but the haptics are constrained by the fibrotic capsule and cannot achieve sufficient movement
Solution Approach 1:
The haptic is segmented into multiple movable sections that can flex and bend independently. This segmentation allows the haptic to maintain lens positioning while each segment can move and deform to navigate the constraints of the fibrotic capsule, achieving both stability and ease of movement.
Solution Approach 2:
The haptic is designed as a flexible structure rather than a rigid one, allowing it to bend and deform within the capsular bag. This flexibility enables the haptic to maintain lens positioning while moving more freely within the constrained environment of the fibrotic capsule.
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 solution allows for improved axial and centrifugal movement of the optic, restoring some of the lost accommodation by reducing the rigidity of the capsular disc through sectioning, allowing the optic to effectively transition between accommodated and unaccommodated states.
Implementation Method 1
The contraction of the ciliary muscle releases zonular tension (accomodative state) and allows the lens to alter to a more globular or spherical resting shape. The relaxation of the ciliary muscle increases tension on zonules and elastic forces in the eye tissue overcome the inherent lens elasticity and result in stretching the lens equator and flattening the lens curvature
Data Source
AI summary
The present invention provides an accommodative intraocular lens (AIOL) system and method for improving accommodation with an intraocular lens. The method involves insertion into the capsular bag of a flexible optic holder comprising a plurality of haptics configured to allow the capsular bag to be sectioned at regular intervals following fusion of the capsular bag. The haptics of the optic holder are designed to allow maximum fusion of the anterior and posterior leaves of the capsular bag following placement of the optic holder in the capsular bag. Following introduction of the optic holder into the capsular bag, the natural or assisted process of fibrosis/fusion of the capsular bag occurs, thereby sealing and securely capturing the haptics within the capsular bag. Subsequently, several cuts are made in the fibrotic capsular bag at intervals between haptics, allowing the haptics to move independently, thereby effectively restoring some of the flexibility that the capsule possessed prior to fibrosis and restoring some of the zonular force on the capsule.