Corneal Laser Scanning for Precise Depth Relief Separation
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Solution Overview
Problem
Current laser technologies for corneal surgery, such as phototherapeutic keratectomy, face challenges in reaching and correcting pathological areas within the corneal stroma, particularly due to difficulties in controlling the laser's movement in the z-direction, which hinders accurate and efficient generation of cavitation bubbles for volume separation.
Innovation Solution
A method and apparatus for controlling a laser to generate cavitation bubbles along circle-like or spiral tracks, using a reference point determined by patient-specific information, allowing for precise depth relief creation and reduced effort in the z-direction, with the laser emitting pulsed pulses in a predefined pattern to define the interfaces of the volume body, and optionally considering the curvature and refractive indices of the cornea.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the entire laser device is moved in the z-direction to generate cavitation bubbles, then the volume body can be separated, but the speed and control of the laser device deteriorate
Solution Approach 1:
The laser device is segmented into a stationary laser source and a movable scanner system. The scanner deflects the laser beam along circular tracks while the main laser device remains stationary, eliminating the need to move the entire laser device in the z-direction and thus maintaining high speed and control.
Solution Approach 2:
A scanner is introduced as an intermediary component between the laser device and the cornea. The scanner deflects the laser beam to create cavitation bubbles along circular tracks, serving as a mediator that enables precise depth relief generation without moving the entire laser device.
2Adaptability or versatility
If additional corneal incision is performed to expose deeper areas, then deeper pathological areas become accessible, but the treatment complexity and patient risk increase
Solution Approach 1:
The method performs preliminary mapping of the corneal topography and determines the depth relief and reference point before treatment. This preliminary action allows the laser to be precisely guided to deeper areas through scanner deflection without requiring additional incisions, thereby accessing deeper pathological areas while maintaining treatment simplicity.
3Manufacturing precision
If the laser device is moved in the z-direction to generate cavitation bubbles, then the volume body can be separated, but the treatment time increases
Solution Approach 1:
The laser is controlled to move in circular tracks with periodic motion patterns. The scanner deflects the laser beam along circular paths at optimized speeds, creating cavitation bubbles through periodic laser pulses. This periodic action maintains high precision in cavitation bubble generation while significantly reducing treatment time compared to linear z-direction movement.
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 enables efficient and accurate generation of cavitation bubbles with reduced effort, allowing for precise separation of volume bodies within the cornea, improving treatment speed and accuracy, especially in the z-direction, and accommodating individual patient needs and corneal geometries.
Implementation Method 1
The interfaces are generated by means of an interaction of the individual laser pulses with the cornea by the generation of a plurality of cavitation bubbles along the circle-like tracks
Implementation Method 2
a so-called phototherapeutic keratectomy (PTA) by means of an ablatively acting laser, for example an excimer laser
Data Source
AI summary
The invention relates to a method for controlling a laser (18) for the separation of a volume body (12) with an anterior interface (16) and with a posterior interface (14):determining a depth relief (48) of the volume body (12) to be generated between the anterior interface (16) and the posterior interface (14);determining a reference point (52) of an axis of symmetry of the determined depth relief (48) or of a respective interface (14, 16) by means of the control device (20);controlling the laser (18) starting from the determined reference point (52) in tracks circle-like at least in certain areas such that it emits pulsed laser pulses in a shot sequence in a predefined pattern into the material, wherein the interfaces are generated by means of an interaction of the individual laser pulses with the cornea (44) by the generation of a plurality of cavitation bubbles (40) along the circle-like tracks. Further, the invention relates to a processing apparatus, to a computer program as well as to a computer-readable medium.