Corneal Incision Scan Control for Low Iris UV Exposure
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Solution Overview
Problem
Laser ophthalmic surgery systems face challenges in safely managing iris exposure during corneal incisions due to the high absorption of ultraviolet radiation by melanin in the iris, leading to potential iris damage without established safety thresholds.
Innovation Solution
A system with a computer control system that adjusts laser treatment scans to maintain iris exposure below a predetermined limit by modifying scan paths, extending turnarounds beyond incision boundaries, reorienting scan axes, or inserting gated rows with active rows, ensuring safe corneal incisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If shorter wavelength laser is used for corneal incision, then cutting precision is improved, but iris absorption increases causing localized heating and potential damage
Solution Approach 1:
The laser treatment scan is divided into multiple segments with different characteristics. Some segments are designed to pass through the iris region without causing damage, while others focus on precise corneal incision. The scan path is segmented into active treatment portions and inactive turnaround portions, allowing differentiation between cutting functions and traversal functions.
Solution Approach 2:
The laser system dynamically adjusts scan parameters including speed, power, and pulse timing based on the current scan position. The control system modifies treatment characteristics in real-time depending on whether the beam is traversing through the iris region or performing corneal incision, enabling adaptive control of energy delivery to prevent iris heating while maintaining cutting precision.
2Productivity
If laser scan speed is increased to improve productivity, then surgical efficiency is improved, but iris exposure time decreases potentially causing safety issues
Solution Approach 1:
The laser operates in periodic pulsed mode rather than continuous wave, with carefully controlled pulse repetition rates. This periodic action allows thermal diffusion between pulses, preventing cumulative heating of the iris while maintaining high average power for efficient corneal cutting. The pulse timing is synchronized with the scan motion to ensure safe exposure intervals.
Solution Approach 2:
The system dynamically changes multiple laser parameters including pulse width, repetition rate, and energy per pulse based on scan conditions. When traversing through or near the iris region, parameters are adjusted to reduce energy delivery and increase pulse intervals, while during corneal incision phases, parameters are optimized for cutting efficiency, thus balancing productivity and safety.
3Ease of operation
If standard treatment scan is used without modifications, then treatment simplicity is maintained, but iris exposure exceeds safe limits
Solution Approach 1:
The control system performs preliminary calculation and simulation of the treatment scan before actual delivery, predicting the iris exposure based on the planned corneal incision pattern. This preliminary action allows identification of potential safety issues and automatic generation of modified scan paths that avoid excessive iris exposure, maintaining ease of operation while ensuring safety.
Solution Approach 2:
The system incorporates feedback mechanisms where the actual iris exposure is monitored and compared against safety thresholds during treatment. The control system uses this feedback to make real-time adjustments to the scan parameters, ensuring that exposure limits are not exceeded while maintaining treatment effectiveness. This closed-loop control preserves operational simplicity through automation.
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 effectively reduces iris exposure to safe levels, preventing damage while creating precise corneal incisions, thereby enhancing surgical safety and efficacy.
Implementation Method 1
the energy that can be used to make cuts is limited by the amount of light that can be safely exposure to non-target tissues
Implementation Method 2
Laser ophthalmic surgery systems are well known and can be used to make incisions in various ocular tissues, including the cornea
Implementation Method 3
Melanin in the iris is also much more absorptive of ultraviolet radiation. As a result, use of shorter wavelength for laser surgery can result in higher absorption, which can give rise to localized heating in the iris
Data Source
AI summary
A laser surgical method for performing a corneal incision while maintaining iris exposure below a predetermined exposure limit includes: determining an initial iris exposure based on an initial treatment scan, determining whether the initial iris exposure is less than the predetermined exposure limit, generating a revised treatment scan comprising one or more treatment scan modifying elements when the initial iris exposure is greater than the predetermined exposure limit, and scanning the focal zone of a pulsed laser beam according to the revised treatment scan, thereby performing the corneal incision, wherein the one or more treatment scan modifying elements causes the iris exposure to be smaller than the predetermined exposure limit.