Lenticular Laser Incision Scanning for Smooth Corneal Dissection
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Solution Overview
Problem
Current femtosecond laser surgery systems for correcting hyperopia using the SmILE technique face challenges in generating smooth lenticular incisions due to the lack of use of the 'fast-scan-slow-sweep' scanning scheme with high repetition rate lasers, resulting in vertical 'steps' and inefficient tissue removal.
Innovation Solution
An ophthalmic surgical laser system incorporating a laser delivery system, an XY-scan device, a Z-scan device, and a controller to form smooth top and bottom lenticular incisions using a 'fast-scan-slow-sweep' scanning scheme, ensuring tangential scan lines and slow sweeps along the meridians of longitude, allowing for precise and smooth lenticular dissection surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional scanning schemes are used with femtosecond lasers, then the laser system can operate with high repetition rate, but the resulting lenticular incisions have vertical steps and are not smooth
Solution Approach 1:
The patent applies dynamic scanning by moving the laser focus along the surface of the lenticule in a spiral or radial pattern rather than using conventional linear scanning. This dynamic approach allows the laser to maintain constant engagement with the tissue surface, creating smooth incisions without vertical steps while operating at high repetition rates.
Solution Approach 2:
The patent transitions from two-dimensional linear scanning to three-dimensional surface scanning by moving the laser focus along the curved surface of the lenticule. This dimensional change enables the laser to follow the natural curvature of the tissue, producing smooth incisions that conform to the lenticule geometry while maintaining high processing speed.
2Device complexity
If conventional scanning schemes are used, then the system structure remains simple, but tissue removal efficiency is poor and incisions are not smooth
Solution Approach 1:
The scanning system employs dynamic motion patterns where the laser focus moves continuously along the lenticule surface in spiral or radial trajectories. This dynamic scanning approach improves tissue removal efficiency and incision smoothness without requiring complex additional hardware, leveraging the existing laser and scanning mirror capabilities.
Solution Approach 2:
The patent changes the scanning parameters including scan pattern (spiral or radial), scan speed, and focus positioning to optimize both tissue removal efficiency and incision quality. By adjusting these parameters, the system achieves smooth incisions and efficient tissue removal while maintaining a relatively simple device structure.
3Speed
If high repetition rate lasers are used without proper scanning, then processing speed is high, but vertical steps are created in the incisions
Solution Approach 1:
The patent uses dynamic scanning patterns where the laser focus moves continuously along the lenticule surface rather than scanning in fixed linear paths. This continuous motion at high repetition rates prevents the formation of vertical steps by ensuring uniform energy distribution along the incision path, thereby maintaining both high processing speed and smooth incision surfaces.
Solution Approach 2:
The patent moves the laser scanning from a two-dimensional planar path to a three-dimensional surface-following path that conforms to the lenticule curvature. This dimensional transition allows high repetition rate lasers to create smooth incisions by maintaining constant surface engagement, eliminating vertical steps while preserving high processing speed.
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 system enables the creation of smooth lenticular incisions, minimizing deviations and allowing for the extraction of lenticular tissue as a single unbroken piece, reducing light scattering and improving the merging of corneal surfaces post-extraction.
Implementation Method 1
a laser delivery system for delivering a pulsed laser beam to a target in a subject's eye
Data Source
AI summary
Embodiments of this invention generally relate to ophthalmic laser procedures and, more particularly, to systems and methods for lenticular laser incision. In an embodiment, an ophthalmic surgical laser system comprises a laser delivery system for delivering a pulsed laser beam to a target in a subject's eye, an XY-scan device to deflect the pulsed laser beam, a Z-scan device to modify a depth of a focus of the pulsed laser beam, and a controller configured to form a top lenticular incision and a bottom lenticular incision of a lens in the subject's eye, where each of the top and bottom lenticular incision includes a center concave portion and an edge transition portion that has a smooth convex shape and is smoothly joined to the center concave portion.