Spatio-temporal modulator for ophthalmic laser beam distortion
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Solution Overview
Problem
Surgical laser systems face challenges in maintaining the required pulse energy density due to beam distortions caused by corneal wrinkling during ophthalmic surgeries, leading to uncut regions and reduced precision in procedures like cataract surgery.
Innovation Solution
Incorporating a spatio-temporal modulator that performs space- and time-dependent modulation of the laser beam to counteract aberrations and maintain beam intensity above the plasma threshold, even in the presence of corneal wrinkling, thereby ensuring effective photodisruption throughout the surgical volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the laser beam is delivered with high energy density to maintain precision, then the photodisruption threshold is exceeded, but beam distortions from corneal wrinkling cause the focus spot to enlarge and reduce beam intensity below the threshold
Solution Approach 1:
The spatio-temporal modulator applies preliminary phase compensation to the laser beam before it reaches the cornea, pre-correcting for the expected distortion effects. This advance action ensures that when the beam passes through the wrinkled cornea, the focus spot remains compact and the beam intensity stays above the plasma threshold, maintaining surgical precision without requiring post-distortion correction.
Solution Approach 2:
The system incorporates real-time feedback through wavefront sensing that continuously monitors the actual beam distortion caused by corneal wrinkling. The spatio-temporal modulator then adjusts its phase compensation in response to this feedback, dynamically adapting to changing corneal conditions during surgery to maintain optimal beam focus and intensity throughout the surgical volume.
2Reliability
If the laser energy is increased to compensate for beam distortions, then the beam intensity remains above the plasma threshold, but collateral damage and shockwaves increase
Solution Approach 1:
Instead of increasing the overall laser energy, the system changes the spatial distribution parameters of the beam by applying spatio-temporal phase modulation. This redistributes the beam energy more effectively across the focal region, compensating for distortions through parameter optimization rather than energy escalation, thereby avoiding excessive heating and shockwaves while maintaining sufficient beam intensity for complete cuts.
3Illumination intensity
If the focus spot size is reduced to increase beam intensity, then the plasma threshold is exceeded, but optical distortions cause the focus spot to enlarge
Solution Approach 1:
The spatio-temporal modulator applies preliminary phase compensation to the laser beam before it reaches the cornea, pre-correcting for the expected distortion effects. This advance action ensures that when the beam passes through the wrinkled cornea, the focus spot remains compact and the beam intensity stays above the plasma threshold, maintaining surgical precision without requiring post-distortion correction.
Solution Approach 2:
The system changes the spatial distribution parameters of the beam by applying spatio-temporal phase modulation. This redistributes the beam energy more effectively across the focal region, compensating for distortions through parameter optimization rather than energy escalation, thereby avoiding excessive heating and shockwaves while maintaining sufficient beam intensity for complete cuts.
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 spatio-temporal modulator significantly reduces the extent of uncut regions, allowing for precise and complete surgical cuts without increasing laser energy, minimizing collateral damage and maintaining high precision in ophthalmic procedures.
Implementation Method 1
a spatio-temporal modulator, configured to perform a space- and time dependent modulation of the laser beam
Implementation Method 2
Each laser pulse can create a plasma or cavitation bubble in the target tissue at the focus spot of the laser beam when the beam intensity or energy density exceeds a plasma or photodisruption threshold
Data Source
AI summary
A surgical laser system can include a laser engine to generate a laser beam of laser pulses; a scanning delivery system to direct the laser beam to a target region and to scan the laser beam along a scan-pattern in the target region; and a spatio-temporal modulator to perform a space- and time dependent modulation of the laser beam. The spatio-temporal modulation of the phases or amplitudes of the beam components can reduce or even eliminate uncut regions in the target region, caused by the destructive interference of the beam components brought about by a wrinkling of a portion of the target or by other beam distorting factors.