Ophthalmic Laser Alignment with 3D Eye Reference Structures
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Solution Overview
Problem
Existing ophthalmic laser systems for refractive correction face alignment errors due to variations in eye alignment during measurement and treatment phases, leading to positioning and alignment issues in three-dimensional incision patterns, which can be exacerbated by poor fixation or slippage of the patient interface.
Innovation Solution
An ophthalmic device that includes a measurement system to capture eye structures, a circuit to determine reference structures about the anterior chamber, and a scanner system to direct a pulsed laser beam based on a three-dimensional treatment model, aligning and positioning the treatment pattern without requiring eye fixation on a target.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the patient gazes at a fixation target during measurement and treatment phases, then the alignment of the eye to the laser system is established, but alignment errors occur due to variations in eye alignment and fixation target dependency
Solution Approach 1:
The patent introduces an intermediary alignment process using reference markings on the patient's eye and image processing software. Instead of relying solely on fixation target gazing, the system captures images of the eye with reference markings and automatically determines the eye's three-dimensional orientation through image processing, eliminating the need for continuous fixation target dependency while improving alignment reliability.
Solution Approach 2:
The patent replaces the mechanical/physical fixation target gazing method with an optical imaging and computational geometry approach. The system uses cameras to capture images of reference markings on the eye, then employs algorithms to calculate the eye's orientation in three-dimensional space, substituting the physical fixation mechanism with a digital imaging and processing system.
2Stability of the object's composition
If the patient interface is affixed to the eye, then the eye position is stabilized, but positioning errors occur due to interface slippage and eye movement
Solution Approach 1:
The patent implements a feedback mechanism where the system continuously monitors the eye's position and orientation through image capture and processing. The automatically determined eye orientation is fed back to adjust the treatment planning and delivery parameters in real-time, compensating for any slippage or movement and maintaining positioning accuracy despite interface instability.
Solution Approach 2:
The patent transitions from a static fixation approach to a dynamic adjustment system. The eye orientation is continuously determined through image processing and the treatment parameters are dynamically adjusted to account for any changes in eye position or orientation, allowing the system to adapt to slippage and movement rather than relying on a fixed interface position.
3Measurement precision
If reference markings are used for alignment, then the three-dimensional treatment model can be positioned, but the markings may not be visible upon contact with the patient interface
Solution Approach 1:
The patent changes the parameters of the reference markings by using physiological features of the eye (such as the corneal reflex, iris patterns, or limbus) instead of external artificial markings. These physiological features are inherently visible and detectable through optical imaging even when the patient interface is in contact with the eye, eliminating the visibility problem while maintaining alignment precision.
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 precise alignment and positioning of the three-dimensional treatment pattern by using reference structures and displaced positioning points, reducing alignment errors and improving the accuracy of refractive corrections.
Implementation Method 1
a laser source (11) configured to generate a pulsed laser beam (L)
Implementation Method 2
an application head (14) with a focusing optic (12)... wherein the focusing optic (12) is configured to focus the pulsed laser beam (L) in the eye (2)
Implementation Method 3
a measurement system (16) configured to optically capture structures of the eye (2) when the application head (14) is affixed to the eye (2)
Implementation Method 4
a scanner system (17) configured to direct the pulsed laser beam (L), in accordance with the three-dimensional treatment model (M3), onto treatment targets (F) of the three-dimensional treatment pattern (3)
Data Source
AI summary
An ophthalmic device for treating an eye includes a laser source, a scanner system and an application head with a focusing optic and a patient interface for docking the application head onto the eye. Moreover, the ophthalmic device includes a measurement system for optically capturing eye structures when the application head is docked to the eye and a circuit which is configured to determine reference structures of the eye, which are arranged in ring-shaped fashion about the center axis of the anterior chamber of the eye, from the captured eye structures and to arrange a defined three-dimensional treatment model with respect to these reference structures in order to process a three-dimensional treatment pattern in accordance with the arranged three-dimensional treatment model in the eye.