Corneal Ablation Laser Energy Measurement Feedback Control
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Solution Overview
Problem
Existing laser systems for corneal ablation face challenges in accurately delivering laser energy to the cornea, leading to potential over-removal of corneal material due to energy fluctuations, which can result in insufficient or excessive correction of ametropia.
Innovation Solution
A laser system with a device for measuring the energy of laser beam pulses after they exit optical means, coupled to a control device that adjusts the operation of the laser source to ensure that only the intended amount of energy is delivered to the cornea, by terminating the laser source if energy thresholds are exceeded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the device for measuring energy is arranged directly behind the laser source, then the measurement is simple and direct, but the measured values do not reflect the actual energy reaching the cornea due to optical means losses
Solution Approach 1:
The patent introduces an intermediary measurement device positioned between the optical means and the cornea. This mediator captures a portion of the laser beam after it passes through the optical means, allowing indirect measurement of the actual energy reaching the cornea without disrupting the main treatment beam path.
Solution Approach 2:
The measurement device provides real-time feedback on the actual energy reaching the cornea, which is then used to adjust the laser source output dynamically. This closed-loop feedback system ensures that despite variations in optical means transmission, the cornea receives the intended energy level.
2Ease of operation
If the laser source operates with fixed power settings, then the system is simple to control, but energy fluctuations cause over-removal or under-removal of corneal material
Solution Approach 1:
The patent transitions from static fixed power settings to dynamic power adjustment. The laser source power is continuously modified based on real-time measurements of actual energy delivery, allowing the system to adapt to variations in optical means transmission and maintain precise ablation throughout the procedure.
Solution Approach 2:
The patent dynamically changes the laser source operating parameters (power output) based on measured energy levels. When the measurement device detects that actual energy delivery deviates from the intended energy, the control system adjusts the laser source parameters to compensate, ensuring consistent ablation precision.
3Reliability
If more laser beam pulses are delivered to the cornea to ensure sufficient treatment, then complete correction is achieved, but excessive material removal occurs leading to overcorrection
Solution Approach 1:
The measurement device provides continuous feedback on the cumulative energy delivered to the cornea. The control system uses this feedback to monitor the total material removal and terminate the procedure when the intended correction is achieved, preventing overcorrection while ensuring complete treatment.
Solution Approach 2:
The patent intentionally delivers slightly less energy per pulse than the maximum possible, using multiple pulses with real-time monitoring. This partial action approach, combined with feedback control, ensures that the cumulative effect achieves the desired correction without exceeding safe limits and causing overcorrection.
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 solution ensures that no more material than planned is removed from the cornea, preventing overcorrection and ensuring precise energy delivery, thereby maintaining the integrity of the corneal tissue.
Implementation Method 1
the energy of the laser beam pulses can be measured by a suitable device
Implementation Method 2
the laser source emits laser beam pulses
Implementation Method 3
the laser beam pulses are given a predetermined intensity profile
Implementation Method 4
In the target device, the laser beam pulses are deflected in different directions
Implementation Method 5
laser system for ablating cornea on a patient's eye
Implementation Method 6
Too much material would then be removed from the cornea
Data Source
Figure 1
Figure 2
AI summary
The laser system (10') has a laser source (14) transmitting a laser-beam pulse (18) in operation, where the laser-beam pulse is changed by a beam shaping lens (20) before emerging from the system. An energy sensor (26) measures energy of the laser-beam pulse emerging from the shaping lens, and is connected with a central control unit (16). The control unit causes stopping of operation of the laser source, when amount of energy of another laser-beam pulse (18') emitted for beginning of laser ablation exceeds a predetermined threshold value. An independent claim is also included for a method for operating a laser system for ablating cornea in a patient eye.