Lenticular Laser Incision Using Wavefront Maps
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Solution Overview
Problem
Current laser surgery systems for correcting hyperopia using SMILE procedures face challenges with smooth lenticular dissection surfaces due to the generation of vertical 'steps' and require many side cuts, and existing measurement methods for refractive corrections have high error rates and fail to account for higher order aberrations.
Innovation Solution
An ophthalmic surgical laser system incorporating a wavefront aberrometer, XY-scan device, and Z-scan device to form precise top and bottom lenticular incisions using a 'fast-scan-slow-sweep' scanning scheme, ensuring smooth lenticular cuts and accounting for iris distortion and higher order aberrations through wavefront-guided measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional laser scanning methods are used to create lenticular incisions, then the procedure can be completed, but vertical steps are generated on the lenticular surface requiring multiple side cuts to achieve smooth dissection
Solution Approach 1:
The patent applies dynamics by making the scan line orientation adaptive rather than fixed. The scan line dynamically adjusts its orientation to remain tangential to the parallels of latitude of the lens at each position, allowing the laser to follow the curved lenticular surface geometry and eliminate vertical steps without requiring multiple side cuts.
Solution Approach 2:
The patent changes the scanning parameters by moving from a fixed Cartesian scanning pattern to a spherical coordinate-based pattern. The scan line orientation parameter is changed to follow the curvature of the lenticular surface, with the scan line angle varying as a function of position on the lens surface, thereby achieving smooth dissection.
2Measurement precision
If traditional refraction measurement methods are used, then the measurement process is simple, but error rates are high and higher order aberrations are not accounted for
Solution Approach 1:
The patent introduces wavefront aberrometry as an intermediary measurement technique between traditional refraction and laser correction. The wavefront aberrometer serves as a mediator that captures complete optical information including higher order aberrations, which then guides the laser incision pattern to achieve more precise refractive correction.
Solution Approach 2:
The patent replaces traditional mechanical refraction measurement methods with optical wavefront sensing. Instead of using mechanical phoropters and subjective patient responses, the system uses optical interferometry to objectively measure the wavefront of light passing through the eye, thereby capturing higher order aberrations with greater precision.
3Reliability
If the cornea is reshaped by removing ring-shaped stroma material in LASIK, then positive focusing power is added to correct hyperopia, but the procedure requires creating and lifting a corneal flap
Solution Approach 1:
The patent extracts only the essential function of tissue removal for hyperopia correction, eliminating the need for flap creation and lifting. By using lenticular incisions that directly remove or reshape the necessary corneal tissue, the procedure achieves the same optical correction without the additional surgical steps of flap manipulation.
Solution Approach 2:
The patent performs preliminary lenticular incisions that create self-contained dissection planes within the cornea. These incisions are designed to allow tissue removal or reshaping while maintaining corneal integrity, eliminating the need for preliminary flap creation and subsequent flap repositioning steps.
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 achieves precise and smooth lenticular incisions, reducing error rates and effectively correcting refractive errors, including higher order aberrations, while ensuring optimal merging of corneal surfaces post-procedure.
Implementation Method 1
a wavefront aberrometer, configured to obtain a wavefront map of an eye in its natural state to measure a refractive error
Implementation Method 2
The SMILE technique involves tissue removal with two femtosecond laser incisions that intersect to create a lenticule
Implementation Method 3
Photoablation of the corneal stroma reshapes the cornea and corrects the refractive condition
Implementation Method 4
an XY-scan device to deflect the pulsed laser beam, a Z-scan device to modify a depth of a focus of the pulsed laser beam
Data Source
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AI summary
Embodiments generally relate to systems and methods for lenticular laser incisions based on wavefront maps. In an embodiment, a method comprises obtaining a wavefront map of a free eye using wavefront aberrometry to measure a refractive error, obtaining an iris image for the free eye using wavefront aberrometry, determining a free eye cutting profile to cut the cornea based on the wavefront measurement, determining a first translation of the free eye cutting profile based on estimated perturbation of the eye with a docking patient interface, docking the eye to a patient interface of an ultrashort pulsed laser system, obtaining an iris image for the docked eye, determining a second translation of the cutting profile for the docked eye from the free eye, using comparisons between the two iris images, and incising a bottom surface incision in the cornea based on the two translated cutting profiles.