Lenticular Laser Incision Scanning for Smooth Corneal Extraction
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Solution Overview
Problem
Conventional femtosecond laser systems fail to generate smooth lenticular incisions for hyperopia correction due to the use of inefficient scanning schemes, leading to vertical 'steps' and difficulties in extracting a ring-shaped stroma material without a corneal flap, resulting in unpredictable removal and increased light scattering.
Innovation Solution
An ophthalmic surgical laser system employing a fast-scan-slow-sweep scanning scheme with a femtosecond laser to create top and bottom lenticular incisions, tangential to the parallels of latitude and along the meridians of longitude, ensuring a smooth and symmetrical extraction of a concave lens-shaped stroma material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional scanning schemes are used to create lenticular incisions, then the laser can remove stroma material, but vertical steps are generated and the incision surface becomes rough
Solution Approach 1:
The patent applies dynamics by making the scan line orientation variable rather than fixed. The scan line direction is dynamically adjusted to be always perpendicular to the radial direction from the corneal center, ensuring the laser follows the curved geometry of the cornea and eliminates vertical steps in the incision surface.
Solution Approach 2:
The patent changes the scanning parameters by modifying the scan line orientation angle as a function of position. Instead of using a fixed scan direction, the scan angle θ is changed according to the radial position, allowing the laser to adapt to the corneal curvature and produce a smooth incision surface without vertical artifacts.
2Ease of operation
If ring-shaped stroma material is removed without creating a corneal flap, then the procedure is simplified, but extraction becomes unpredictable and control is lost
Solution Approach 1:
The patent segments the lenticular incision into multiple concentric rings or zones that are removed sequentially or simultaneously. This segmentation allows the stroma material to be extracted in a controlled manner through a small incision, maintaining predictability while avoiding the need for a large corneal flap.
Solution Approach 2:
The patent uses the natural curvature and geometry of the cornea to facilitate extraction. By designing the lenticular incision to follow the corneal curvature and creating a tapered or curved extraction path, the stroma material can be removed predictably through a small incision without requiring a large flap.
3Device complexity
If the scan line is not tangential to the corneal curvature, then scanning is simpler, but the incision surface develops vertical steps
Solution Approach 1:
The patent applies dynamics by making the scan line orientation variable rather than fixed. The scan line direction is dynamically adjusted to be always perpendicular to the radial direction from the corneal center, ensuring the laser follows the curved geometry of the cornea and eliminates vertical steps in the incision surface.
Solution Approach 2:
The patent adds an angular dimension to the scanning control by introducing the orientation angle θ that varies with radial position. This transforms the scanning from a simple two-dimensional pattern to a three-dimensional adaptive pattern that conforms to the corneal surface curvature, eliminating vertical steps.
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 precise, smooth extraction of a lenticular incision without vertical steps, minimizing light scattering and ensuring ideal merging of corneal surfaces, thereby effectively correcting hyperopia with reduced optical aberrations.
Implementation Method 1
a laser delivery system for delivering a pulsed laser beam to a target in a subject's eye
Data Source
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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.