Corneal Resection Depth Control Using Biomechanical Modeling
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Solution Overview
Problem
Current corneal transplant procedures, such as posterior lamellar keratoplasty and femtosecond laser-based methods, face challenges including difficulty in performing the procedures, post-operative astigmatism, irregular surface healing, and risk of tissue weakening due to corneal distortion and ectasia.
Innovation Solution
A system and method using a surgical laser with a focusing assembly and a biomechanical model to determine and make precise resection incisions in corneal tissue, minimizing surface irregularities and post-operative weakening by selecting optimal resection depths based on corneal thickness and curvature, with optional use of contact lenses to conform the cornea and ensure uniform incision distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a resection incision is made too near the posterior surface of the cornea, then the procedure can be performed, but the folds or wrinkles cause the incision to have an irregular surface that adversely affects wound healing and optical quality
Solution Approach 1:
The system performs preliminary measurement of corneal thickness and curvature using optical coherence tomography before making the resection incision. This allows the laser to be positioned at an optimal depth that avoids the posterior surface where folds and wrinkles occur, ensuring a regular incision surface while maintaining ease of operation
2Ease of operation
If the resection incision is made too near the anterior surface of the cornea, then the procedure can be performed, but the anterior portion becomes overly thinned causing the cornea to weaken and deteriorate due to ectasia
Solution Approach 1:
The system measures corneal thickness and curvature beforehand using optical coherence tomography, then uses this data to calculate and position the laser incision at an optimal depth. This ensures sufficient anterior tissue remains to prevent ectasia while allowing the procedure to be performed easily
Solution Approach 2:
The system incorporates real-time feedback from preoperative measurements of corneal thickness and curvature to dynamically determine the optimal incision depth. This feedback mechanism ensures the incision is positioned to maintain corneal strength while facilitating easy procedure performance
3Measurement precision
If contact lenses are used with femtosecond lasers to provide proper registration, then the laser can focus properly, but the contact lenses distort the shape of the cornea introducing folds or wrinkles
Solution Approach 1:
The system performs preliminary measurement of corneal thickness and curvature using optical coherence tomography before placing contact lenses. This allows the system to map the cornea's natural shape and use this information to position the laser incision at an optimal depth that compensates for any distortion caused by contact lenses, maintaining both focusing precision and corneal shape integrity
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 approach improves the precision and stability of corneal resection, reducing post-operative complications like astigmatism and ectasia, while maintaining optical quality and ensuring proper wound healing.
Implementation Method 1
a surgical laser emits a pulsed laser beam which is directed into the cornea by a focusing assembly
Implementation Method 2
the exposed ocular tissue is ablated or excised through the process of optical breakdown or photodisruption
Implementation Method 3
contact lenses, both flat and curved, are generally used with femtosecond lasers in order to provide proper registration of the cornea with the focal point of the pulsed laser beam. These contact lenses distort the shape of the cornea by forcing the anterior surface of the cornea to conform to the curvature of the lens
Data Source
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AI summary
A system and method for resecting and transplanting corneal tissue is disclosed. In a recipient cornea, a resection depth from the anterior surface of the recipient cornea is determined based upon a biomechanical model of the recipient cornea. A resection incision for resecting a posterior portion of the recipient cornea is made at the resection depth. Preferably, the incision is made using a surgical laser. Optionally, a contact lens may be placed against the anterior surface of the recipient cornea, wherein the shape of the anterior surface is conformed to the shape of the contact lens.