Birefringent Intracorneal Lenticule for Stable Refractive Alignment
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Solution Overview
Problem
Conventional intracorneal implants for correcting refractive errors face challenges such as limited donor cornea availability, potential corneal weakening, epithelial healing issues, and difficulty in precise alignment, leading to unpredictable refractive performance and visual degradation.
Innovation Solution
A decellularized birefringent lenticule derived from corneal donor tissue with anisotropic collagen fibers, exhibiting different refractive indices along two orientations, is implanted in the stromal layer to correct refractive errors without shape transfer, using femtosecond laser to create a pocket for precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional additive techniques use flaps to implant lenticules, then lenticule implantation is achieved, but corneal weakening and potential long-term drift in refraction occur
Solution Approach 1:
The patent extracts and removes the harmful flap creation step from the implantation process. Instead of creating flaps to access the stromal bed, the invention uses a needle-based delivery system that injects the lenticule directly into the predetermined intrastromal location through a small puncture, eliminating the need for extensive flap dissection and reducing corneal structural compromise
Solution Approach 2:
The patent introduces a needle-based delivery system as an intermediary tool between the lenticule and the corneal stroma. This intermediary mechanism enables precise placement of the lenticule into the intrastromal bed through minimal incision, avoiding the need for large flaps and reducing trauma to the corneal structure
2Ease of operation
If conventional lenticules are made very pliable for insertion, then insertion into corneal pockets is facilitated, but spatial alignment with visual axis becomes difficult
Solution Approach 1:
The patent performs preliminary shaping and orientation of the lenticule before insertion. The lenticule is pre-formed with the correct curvature and optical properties, and the needle delivery system is designed to maintain the lenticule's orientation during insertion, ensuring proper alignment with the visual axis is achieved automatically through the predetermined injection trajectory
Solution Approach 2:
The patent replaces the manual mechanical alignment process with a guided injection system. The needle-based delivery mechanism uses controlled injection forces and a predetermined insertion path to automatically position the lenticule at the correct location and orientation, substituting surgeon manual alignment with a more precise mechanical guidance system
3Reliability
If small diameter lenticules are used for presbyopia correction, then refractive error correction is achieved, but epithelial healing diminishes the shape transfer effect
Solution Approach 1:
The patent extracts and eliminates the shape transfer mechanism that is vulnerable to epithelial healing. Instead of relying on the lenticule to reshape the anterior corneal surface through epithelial remodeling, the invention creates an intrastromal pocket that physically holds the lenticule in place, where it directly modifies the corneal refractive power through its optical properties without depending on epithelial shape changes
4Reliability
If precise alignment of lenticule with visual axis is required, then optimal refractive performance is achieved, but alignment difficulty increases even for experienced surgeons
Solution Approach 1:
The patent performs preliminary marking and planning of the injection trajectory before the actual lenticule insertion. The surgeon pre-determines the optimal entry point and angle of injection based on the patient's visual axis and desired lenticule location, allowing for more accurate and repeatable alignment without increasing procedural complexity
Solution Approach 2:
The patent introduces a needle-based delivery system as an intermediary that acts as a mechanical guide for lenticule placement. The needle's fixed trajectory and depth control serve as a mediator between the surgeon's intent and the final lenticule position, making precise alignment more achievable and consistent
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 lenticule provides stable refractive correction with minimal corneal curvature change, reducing the risk of complications like dry eye and ectasia, and achieving precise alignment for improved visual acuity.
Implementation Method 1
The decellularized lenticular body includes collagen fibers distributed therein such that the lenticular body exhibits birefringence to visible light
Implementation Method 2
the lenticular body exhibits birefringence to visible light and further exhibits sufficient optical clarity for intrastromal implantation
Implementation Method 3
Techniques that utilize femtosecond laser radiation to make surgical cuts in the cornea for forming a corneal pocket into which a lenticule can be inserted
Data Source
AI summary
In one aspect, a collagenous lenticule for use in intrastromal implantation is disclosed, which includes a decellularized lenticular body derived from a corneal donor source having an anterior surface and a posterior surface, where the decellularized lenticular body includes collagen fibers distributed therein such that the lenticular body exhibits birefringence to visible light and further exhibits sufficient optical clarity for intrastromal implantation. A lenticule according to the present teachings can be implanted in a patient's stromal layer to correct a refractive error of the eye, such as presbyopia.