Haptic Optic Accommodation Intraocular Lens
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Solution Overview
Problem
Existing accommodating intraocular lenses face challenges in efficiently converting ocular forces into changes in lens power and axial location, leading to limited accommodation range and potential eye fatigue.
Innovation Solution
The design incorporates a haptic with greater stiffness than the optic, which protrudes into the optic's annular recess, allowing for efficient force transmission to alter the optic's shape and power, and matching refractive indices to minimize light reflection, thereby enhancing the lens's ability to accommodate over a wider range with reduced ocular force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a haptic is used to couple the optic to the capsular bag, then the optic can be mechanically supported and forces can be transmitted, but the efficiency of converting ocular force to change in power and axial location is insufficient
Solution Approach 1:
The haptic is positioned within an annular recess of the optic, creating a nested configuration where the haptic protrudes into the recess. This nesting arrangement allows the haptic to be surrounded by the optic material, improving the transmission of forces from the capsular bag through the haptic to the optic, thereby increasing the efficiency of converting ocular force to changes in lens power and axial location.
2Force
If the haptic stiffness is increased to improve force transmission, then the efficiency of force transmission improves, but the haptic may cause undesirable pressures on eye structures
Solution Approach 1:
The haptic is configured with specific local properties: it has a greater stiffness than the optic to ensure efficient force transmission, but it is positioned within the annular recess which allows it to be surrounded by the softer optic material. This local configuration enables the haptic to transmit forces effectively while the surrounding optic material distributes and reduces undesirable pressures on eye structures.
Solution Approach 2:
The system uses composite material properties where the haptic has different stiffness characteristics than the optic. The haptic is made with material properties that provide greater stiffness for force transmission, while the optic material provides a softer surrounding medium that distributes pressures. This composite approach allows simultaneous achievement of high force transmission efficiency and reduced harmful pressures.
3Object-generated harmful factors
If the haptic refractive index is matched to the optic refractive index, then light reflection at the interface is minimized, but the haptic material selection becomes more constrained
Solution Approach 1:
The haptic and optic are designed with matched refractive indices, creating optical homogeneity at their interface. This refractive index matching eliminates visible boundaries and minimizes light reflection, making the haptic optically invisible. The patent specifies that the haptic refractive index should be essentially equal to the optic refractive index, achieving homogeneous optical properties despite the mechanical heterogeneity needed for force transmission.
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
This configuration achieves a larger change in power and axial translation of the image, exceeding the typical 4 diopter accommodation range with reduced ocular force, thereby improving vision and reducing eye fatigue.
Implementation Method 1
The haptic is configured to transmit forces to alter at least one of the shape or the thickness of the adjustable optic
Implementation Method 2
The haptic stiffness is greater than the optic stiffness
Implementation Method 3
The haptic refractive index is essentially equal to the optic refractive index
Data Source
Figure 1~2
Figure 3
Figure 4~9
AI summary
An intraocular lens is disclosed, with an optic that changes shape in response to a deforming force exerted by the zonules of the eye. A haptic (120) supports the optic around its equator and couples the optic to the capsular bag of the eye. The region of contact between the optic and the haptic extends into the edge of the optic (130), similar to the interface between a bicycle tire and the rim that holds it in place. The haptic may be stiffer than the optic. The haptic may have the same refractive index as the optic. The haptic may include a saddle-shaped portion in contact with the adjustable optic, with a convex profile along an optical axis; and a concave profile in a plane perpendicular to the optical axis.