Purkinjie Reflection Alignment for IOL Centering
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Solution Overview
Problem
Current methods for centering an intraocular lens (IOL) during cataract surgery are inaccurate due to the asymmetric dilation of the pupil, leading to systematic misalignment of the IOL with respect to the visual axis and optic axis of the eye, resulting in optical aberrations and potential displacement of the IOL over time.
Innovation Solution
A Purkinjie reflection-based alignment device using a laser system with a suction ring and a joystick-controlled 3-axis motion control system, which includes a semi-circular light source and a camera to align the suction ring with the optic axis of the eye by imaging Purkinjie reflections from the cornea and crystalline lens surfaces, ensuring precise centering of the IOL.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the anterior capsular opening is centered using the dilated pupil as reference, then the procedure can be accomplished manually, but the IOL becomes systematically off center with respect to the visual axis and optic axis
Solution Approach 1:
The patent replaces manual mechanical centering based on pupil appearance with an optical measurement system that detects Purkinjie reflections. The system uses optical sensors to capture reflection patterns from the cornea and lens surfaces, automatically determining the optic axis position without relying on manual estimation or pupil symmetry.
Solution Approach 2:
The patent introduces Purkinjie reflections as an intermediary visual marker to indicate the optic axis position. These reflections serve as a reliable reference that correlates with the actual optical axis, allowing the suction ring to be positioned accurately without directly observing the pupil or making manual judgments about eye geometry.
2Manufacturing precision
If a laser system with motion control is used to align the suction ring, then IOL placement precision is improved, but device complexity increases
Solution Approach 1:
The patent implements a feedback control system where optical sensors continuously monitor the position of Purkinjie reflections relative to the suction ring. The motion control system receives this positional information and automatically adjusts the suction ring position to achieve optimal alignment, creating a closed-loop control system that improves precision while managing complexity through automated control.
Solution Approach 2:
The patent uses optical copying of the eye's optical characteristics through Purkinjie reflections. Instead of directly measuring physical dimensions or positions, the system captures optical reflection patterns that replicate the eye's geometric information, allowing indirect but accurate measurement of the optic axis position through these optical copies.
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 method allows for more accurate and stable placement of the IOL, reducing optical aberrations and ensuring optimal positioning, thereby improving visual outcomes and minimizing the need for secondary procedures.
Implementation Method 1
A Purkinjie reflection-based alignment device using a laser system with a suction ring and a joystick-controlled 3-axis motion control system, which includes a semi-circular light source and a camera to align the suction ring with the optic axis of the eye by imaging Purkinjie reflections from the cornea and crystalline lens surfaces
Data Source
Figure 1
Figure 2A~3D
AI summary
An alignment device including means for releasably attaching a suction ring and means for applying a pattern of light to an eye of a patient. The alignment device further including means for detecting light reflected from the eye and determining whether the suction ring is aligned relative to the eye based on the detected light.