Eye Surgical Laser Interface Arc Length Control
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Solution Overview
Problem
Existing surgical procedures for removing volume bodies from the cornea often result in uneven arc lengths of the anterior and posterior interfaces, leading to wrinkles, superpositions, and stresses in the cornea, which can prolong recovery times.
Innovation Solution
A method and treatment apparatus where the eye surgical laser emits pulsed laser pulses in a predefined pattern to create interfaces of equal arc length in all radial directions by generating an indentation in one of the interfaces, thereby compensating for length differences and reducing stress on the cornea.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If standard laser separation procedure is used to remove volume body from cornea, then volume body is separated from cornea, but arc lengths of anterior and posterior interfaces become differently long causing wrinkles and stresses
Solution Approach 1:
The patent applies asymmetry by intentionally creating an indentation in one interface to compensate for the natural asymmetry in interface arc lengths. The control device calculates the arc length difference between anterior and posterior interfaces and generates an indentation in the interface with the longer arc length, making the effective arc lengths equal. This asymmetric modification to one interface resolves the harmful effects caused by the original asymmetric interface lengths.
2Productivity
If standard laser separation procedure is used, then volume body is removed efficiently, but recovery time is prolonged due to corneal stresses
Solution Approach 1:
The patent applies preliminary action by calculating and compensating for arc length differences before the actual volume body removal is completed. The control device determines the required indentation depth and position in advance, then generates this indentation during the laser separation process. This preliminary compensation prevents the formation of wrinkles and stresses that would otherwise require time to heal, thereby shortening recovery time while maintaining treatment efficiency.
3Object-generated harmful factors
If interface arc lengths are made equal by adding indentation path, then wrinkles and stresses are avoided, but interface geometry deviates from original progression
Solution Approach 1:
The patent applies local quality by making the indentation only in a specific local region of one interface rather than altering the entire interface geometry. The control device calculates where the indentation should be positioned to achieve equal arc lengths while minimizing deviation from the original interface progression. This localized modification maintains the overall shape and function of the interface while achieving the beneficial effect of equal arc lengths.
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 ensures that the arc lengths of the anterior and posterior interfaces are equal, reducing wrinkles, superpositions, and stresses in the cornea, which results in a gentler treatment and shorter recovery times.
Implementation Method 1
separation of a volume body with a predefined posterior interface and a predefined anterior interface from a human or animal cornea by means of photodisruption and/or photoablation
Implementation Method 2
the interfaces are generated by means of an interaction of the individual laser pulses with the cornea by generating a plurality of cavitation bubbles
Data Source
AI summary
A method is disclosed for controlling an eye surgical laser of a treatment apparatus for the separation of a volume body with a predefined posterior interface and a predefined anterior interface from a human or animal cornea. The method includes controlling the laser with a control device of the treatment apparatus such that it emits pulsed laser pulses in a shot sequence in a predefined pattern into the cornea. The interfaces of the volume body to be separated are defined by the predefined pattern and 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. An arc length of the anterior interface and an arc length of the posterior interface are generated of equal length in all radial directions by at least one indentation in one of the interfaces.