Corneal Flap Cutting Device with Symmetric Undercut Hinge
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Solution Overview
Problem
Current methods for cutting flaps in the cornea during LASIK procedures result in asymmetrical incisions, leading to postoperative corneal deformations and aberrations due to intraocular pressure, as the hinge area remains connected and non-symmetrical, affecting the biomechanical structure and optical axis alignment.
Innovation Solution
A device using femtosecond laser technology with reprogrammed computer control to create a symmetrically cut flap with an undercut design, ensuring the flap is connected at two points under the hinge area, maintaining symmetry and minimizing asymmetrical deformation risks, and allowing for a larger ablation field by offsetting the flap incision from the optical axis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an asymmetrical incision is made to create a hinge area for flap connection, then the flap can be folded back after ablation, but the biomechanical structure of the cornea becomes asymmetrical, leading to postoperative deformations and aberrations due to intraocular pressure
Solution Approach 1:
The patent applies asymmetry principle by intentionally creating a symmetrical incision design (opposite of typical asymmetrical hinge) to compensate for the asymmetry introduced by the hinge area. The incision is made symmetrically around the visual axis, which balances the biomechanical structure and prevents postoperative deformations while still allowing the hinge to function for flap folding.
2Area of stationary object
If the flap incision is positioned to maximize ablation field size, then the ablation area is increased, but the incision becomes asymmetrical relative to the optical axis, causing corneal deformation
Solution Approach 1:
The patent resolves this contradiction by using a symmetrical incision design around the visual axis, which may be slightly offset from the optical axis. This symmetrical approach around a shifted center allows maximizing the ablation field area while maintaining corneal symmetry and preventing deformations.
3Adaptability or versatility
If the hinge area remains connected to the cornea to allow flap refolding, then the flap can be repositioned, but the asymmetrical connection creates uneven stress distribution under intraocular pressure
Solution Approach 1:
The patent applies asymmetry principle by creating a symmetrical incision pattern that compensates for the asymmetrical hinge connection. The symmetrical incision around the visual axis balances the stress distribution in the corneal tissue, maintaining biomechanical stability while preserving the hinge's adaptability for flap repositioning.
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 solution reduces the risk of undesirable postoperative corneal deformations by creating a more symmetrical biomechanical structure, minimizing intraocular pressure-induced bulges and maintaining optical axis alignment, while enabling a larger ablation area through a strategically offset flap incision.
Implementation Method 1
the power density of the radiation when focused inside the cornea causes so-called photo disruptions there. By controlling these femtosecond pulses in space and time, a cut can then be generated in the cornea by a large number of such photo disruptions.
Data Source
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AI summary
The invention relates to a device for cutting a flap in the cornea of eye, said device comprising: a laser radiation source for producing laser radiation, and means for shaping and guiding the laser radiation with regard to the cornea (20) in such a manner that a cut (28) is produced in the cornea and allows the flap (26) to be lifted off the cornea. The cut (28) is produced in the hinge area (22) of the cornea in such a manner as to produce an undercut section (30) below the hinge area (22). In this manner, the intrastromal intervention is substantially carried out in a symmetric way in relation to a center axis of the cornea (20), especially when an fs LASIK is used, so that no undesirable post-operative deformations of the cornea occur due to the intraocular pressure.