Femtosecond Laser PRK System for Corneal Tissue Dissection
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Solution Overview
Problem
Current ophthalmic laser surgery systems for PRK procedures require multiple laser systems, including femtosecond and excimer lasers, which increase costs and are less ideal due to varying tissue ablation rates with corneal hydration levels, and existing methods like LASIK have structural weaknesses and longer recovery times.
Innovation Solution
The use of a femtosecond laser-based system for performing PRK procedures, which includes a laser source generating a pulsed laser beam and a delivery system for anterior surface volume dissection on the cornea, allowing for the removal of corneal tissue to correct refractive errors without the need for multiple laser systems, with a patient interface that constrains the eye and a controller for precise tissue removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple laser systems (femtosecond and excimer lasers) are used for PRK procedures, then comprehensive refractive correction capability is achieved, but system cost and complexity increase
Solution Approach 1:
The femtosecond laser system is designed to perform multiple functions including both corneal flap creation and stromal ablation for PRK procedures, replacing the need for separate excimer laser systems. The system achieves comprehensive refractive correction capability through software-controlled pulse parameter adjustment rather than requiring multiple specialized laser devices.
Solution Approach 2:
The patent combines the functions of femtosecond laser (for flap creation) and excimer laser (for stromal ablation) into a single integrated femtosecond laser system. By merging these previously separate laser systems into one device, the patent reduces overall system complexity while maintaining the ability to perform complete PRK procedures.
2Manufacturing precision
If excimer laser is used for corneal stroma photoablation, then refractive correction is achieved, but tissue ablation rates vary with corneal hydration levels
Solution Approach 1:
The patent changes the fundamental laser parameter from excimer laser ultraviolet pulses to femtosecond laser infrared pulses with durations of 10-300 femtoseconds. This parameter change eliminates the hydration-dependent ablation variability because femtosecond laser ablation operates through a different mechanism (optical breakdown and plasma formation) that is not sensitive to corneal hydration levels, while maintaining precise refractive correction capability.
Solution Approach 2:
The patent replaces the excimer laser photoablation mechanism with femtosecond laser photodisruption mechanism. This substitution changes the physical mechanism from chemical bond breaking (excimer) to optical breakdown and cavitation (femtosecond), resulting in more consistent and predictable tissue removal rates that are independent of corneal hydration state.
3Speed
If LASIK procedure is performed with corneal flap creation, then vision improvement is achieved quickly, but corneal structural strength is reduced
Solution Approach 1:
The patent extracts and removes the problematic corneal flap creation step from the LASIK procedure. By using PRK (photorefractive keratectomy) instead of LASIK, the epithelium is removed and stromal ablation is performed directly on the exposed stroma without creating a flap. This eliminates the structural weakness introduced by flap creation while still achieving vision correction through controlled stromal removal.
Solution Approach 2:
The patent inverts the traditional LASIK approach by removing the flap first (through epithelial debridement in PRK) and then performing ablation, rather than creating a flap to protect the ablation site. This inversion eliminates the structural compromise of flap creation while maintaining the benefits of laser ablation for vision correction.
4Reliability
If LASIK procedure is performed, then vision correction is achieved, but recovery time is extended compared to PRK
Solution Approach 1:
The patent inverts the procedural sequence by performing ablation on exposed stroma without a protective flap (PRK approach) rather than creating a flap to enable ablation (LASIK approach). Although PRK traditionally has longer recovery, the patent's femtosecond laser technology enables more precise and controlled ablation with potentially faster visual rehabilitation, effectively reducing the time loss associated with recovery while maintaining reliable vision correction.
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 provides more consistent and efficient vision correction with improved mechanical strength of the cornea, reduced recovery time, and cost-effective refractive surgery suites capable of performing PRK and other procedures with a single femtosecond laser system, independent of corneal hydration levels.
Implementation Method 1
ultra-short pulsed lasers emit radiation with pulse durations as short as 10 femtoseconds and as long as 3 nanoseconds... A femtosecond laser-based system for performing PRK procedures... anterior surface volume dissection on the cornea
Data Source
AI summary
Embodiments of this invention generally relate to ophthalmic laser procedures and, more particularly, to systems and methods for photorefractive keratectomy. In an embodiment, an ophthalmic surgical laser system comprises a laser source generating a pulsed laser beam and a laser delivery system delivering the pulsed laser beam to a cornea of an eye. A patient interface couples to and constrains the eye relative to the laser delivery system. A controller controls the laser delivery system to perform an anterior surface volume dissection on the cornea.