Intraocular Lens Plunger with Variable Cross-Section
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Solution Overview
Problem
The existing intraocular lens insertion apparatus faces challenges in stabilizing the plunger during the extrusion of the lens due to deformation when the insertion tube and plunger sizes are minimized, leading to increased resistance and potential deformation of the plunger, which can result in unstable lens insertion.
Innovation Solution
The design includes a rod-like plunger with a constant dimension along the optical axis and increased thickness perpendicular to the axis, particularly at a distance from the leading end, to distribute load effectively, minimizing overall plunger dimension increase and reducing deformation, while maintaining a small insertion tube size and incision size, with optional features like tapered sections and rail support for enhanced stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the insertion tube and plunger sizes are decreased to reduce patient burden, then the incision size can be reduced, but the plunger becomes more prone to deformation during extrusion
Solution Approach 1:
The plunger is designed with non-uniform cross-sectional dimensions: the first region (leading end) has smaller dimensions to fit through the reduced-size insertion tube, while the second region (distal end) has larger dimensions perpendicular to the optical axis to resist deformation during extrusion. This local differentiation allows the plunger to simultaneously accommodate small incision requirements while maintaining structural stability during the extrusion process.
2Length of moving object
If the plunger diameter is decreased to match the smaller insertion tube, then the insertion tube size can be reduced, but the resistance acting on the plunger during extrusion increases
Solution Approach 1:
The plunger features region-specific dimensioning where the first region has smaller cross-sectional dimensions to minimize insertion tube size, while the second region has enlarged cross-sectional dimensions perpendicular to the optical axis. This local quality differentiation allows the distal end to withstand higher extrusion forces without deformation, while the leading end remains compact for minimal incision access.
Solution Approach 2:
The plunger's second region increases dimensions specifically in directions perpendicular to the optical axis, while maintaining or reducing dimensions along the optical axis direction. This dimensional differentiation across different spatial directions allows the plunger to resist bending forces (which act perpendicular to the axis) while keeping the overall profile small enough for minimal incision access.
3Reliability
If the plunger dimensions are increased to prevent deformation, then plunger stability improves, but the insertion tube size must increase
Solution Approach 1:
The plunger is designed with spatially varying cross-sectional dimensions: the first region near the leading end has smaller dimensions to accommodate a compact insertion tube, while the second region at the distal end has larger dimensions perpendicular to the optical axis to prevent deformation during extrusion. This localized dimensional differentiation resolves the contradiction by providing structural reinforcement only where needed for stability.
Solution Approach 2:
The plunger is segmented into distinct functional regions: a first region for insertion through the tube with minimized dimensions, and a second region for force resistance with enlarged dimensions. This segmentation allows each region to be optimized for its specific function without compromising the other, enabling small insertion tube size while maintaining plunger stability during extrusion.
Data Source
Figure 1(a)~1(b)
Figure 2(a)~2(b)
Figure 3
AI summary
Provided is technology which can prevent plunger deformation and further stabilize an intraocular lens insertion operation, even when an insertion tube section of an intraocular lens insertion apparatus has been further reduced in terms of the diameter thereof and has been made flatter. The intraocular lens insertion apparatus includes: a tip end region where a plunger comes into contact with an intraocular lens main body and an intraocular lens holding section; and a bar-shaped section extending from the rear end of this tip end region to the rear of the plunger. The bar-shaped section has a fixed thickness in the direction of the optical axis of the intraocular lens, and has an increasing thickness in a portion where the distance from the tip end of the tip end region is equal to or greater than a predetermined distance in a direction perpendicular to the optical axis direction and perpendicular to the plunger advancement direction.