Laser Eye Surgery Calibration via Threshold Mapping
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Solution Overview
Problem
Existing methods for laser-assisted eye surgery, such as cataract treatment and refractive error correction, face challenges with inaccurate optical breakdown location, increased energy usage, and exposure to ultraviolet light, leading to rough tissue cutting and incomplete procedures due to cumbersome patient interfaces and interference with optical coherence tomography measurements.
Innovation Solution
The implementation of a system that maps laser beam focus locations and adjusts energy delivery based on threshold energies to achieve precise optical breakdown, using an optically transmissive patient interface that maintains corneal shape and combines with OCT for improved imaging and extended treatment range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If prior patient interfaces are used to align laser with tissue, then laser alignment is achieved, but intraocular pressure increases and corneal shape is distorted
Solution Approach 1:
The patent removes the physical patient interface component entirely, extracting the alignment function from the interface and implementing it through software-based coordinate transformation and calibration methods. This eliminates the mechanical contact that caused intraocular pressure increase while preserving laser alignment accuracy through computational approaches.
Solution Approach 2:
The patent replaces the mechanical patient interface system with an optical and computational system. Instead of using physical alignment tools that contact the eye, the system uses optical coherence tomography imaging combined with coordinate transformation algorithms to achieve precise laser-tissue alignment without mechanical intervention.
2Measurement precision
If prior patient interfaces are used to align laser with tissue, then laser alignment is achieved, but corneal shape is distorted
Solution Approach 1:
The patent removes the physical patient interface component that caused corneal distortion, extracting the alignment function and implementing it through software-based coordinate transformation. This eliminates the mechanical contact that distorted corneal shape while preserving alignment accuracy through computational methods.
Solution Approach 2:
The patent replaces the mechanical patient interface system with an optical and computational system that images the cornea and uses coordinate transformation algorithms to achieve precise alignment without physical contact, thereby maintaining natural corneal shape.
3Reliability
If excessive laser energy is used to ensure optical breakdown, then complete tissue cutting is achieved, but gas formation increases and tissue damage worsens
Solution Approach 1:
The patent performs preliminary calibration by mapping the actual laser focus locations to the intended target locations before treatment. This preliminary action identifies and corrects systematic deviations, allowing the use of precise, minimal energy levels during actual treatment to achieve complete cutting without excessive gas formation or tissue damage.
Solution Approach 2:
The patent implements a feedback mechanism where the actual laser focus locations are measured and mapped against intended targets, and this information is used to adjust and correct subsequent laser delivery. This closed-loop control ensures optimal energy delivery that achieves complete cutting while minimizing harmful gas formation.
4Productivity
If laser focus locations are not accurately mapped, then treatment speed is maintained, but optical breakdown location accuracy decreases
Solution Approach 1:
The patent performs preliminary mapping of laser focus locations to target locations before treatment begins. This one-time calibration step establishes accurate correspondence between intended and actual focus points, enabling both high precision and maintained treatment speed during the actual surgical procedure.
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 enhances the accuracy of tissue cutting, reduces energy exposure, and minimizes gas formation, resulting in more precise and complete surgical cuts with reduced distortion and improved refractive corrections.
Implementation Method 1
Pulsed lasers can be used to cut one or more of many materials and have been used for laser surgery to cut tissue
Implementation Method 2
photodisruption induced by a pulsed laser beam
Implementation Method 3
an optically transmissive patient interface that maintains corneal shape and combines with OCT for improved imaging
Data Source
AI summary
The amount of energy to provide optical breakdown can be determined based on mapped optical breakdown thresholds of the treatment volume, and the laser energy can be adjusted in response to the mapped breakdown thresholds. The mapping of threshold energies can be combined with depth and lateral calibration in order to determine the location of optical breakdown along the laser beam path for an amount of energy determined based on the mapping. The mapping can be used with look up tables to determine mapped locations from one reference system to another reference system.