Iris Registration for Laser Surgery Using Dual-Mode Imaging
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Solution Overview
Problem
Current iris registration methods fail to accurately track torsional rotation and positional movement of the eye during laser eye surgery due to iris distortions caused by pupil dilation and constriction, leading to misalignment and suboptimal treatment results.
Innovation Solution
The system takes multiple images of the eye under different light conditions to monitor pupil size and iris changes, using variable wavelength and intensity light sources to maintain accurate alignment and tracking of eye movements, thereby improving iris registration and torsional tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional iris registration methods are used, then the system is simple to operate, but alignment accuracy deteriorates due to iris distortions from pupil dilation and constriction
Solution Approach 1:
The system dynamically adapts to changing pupil sizes by using multiple image capture modes (scotopic and photopic) and selectively registering iris features based on the actual pupil size during surgery. This dynamic adaptation resolves the contradiction by maintaining alignment accuracy across varying physiological conditions without requiring a completely complex new system architecture.
Solution Approach 2:
The system changes the illumination parameters (scotopic vs. photopic lighting conditions) to capture iris images under different pupil sizes. By comparing and registering features across these different parameter states, the system achieves accurate alignment regardless of pupil dilation or constriction, thereby improving measurement precision without excessive complexity.
2Measurement precision
If multiple images under different light conditions are captured, then alignment accuracy improves, but the time required for registration increases
Solution Approach 1:
The system performs preliminary image capture under both scotopic and photopic lighting conditions during the diagnostic phase, before surgery begins. This preliminary action ensures that reference images are already available when surgery starts, eliminating the need to capture additional images during the surgical procedure and thus avoiding time loss.
Solution Approach 2:
The system creates multiple copies of iris images under different lighting conditions (scotopic and photopic) and uses algorithmic processing to identify corresponding features across these copies. This copying approach allows rapid comparison and registration without requiring time-consuming manual measurements or adjustments during surgery.
3Reliability
If iris features are used for tracking, then torsional rotation can be monitored, but tracking reliability deteriorates when the pupil dilates or constricts
Solution Approach 1:
The system dynamically selects which iris features to track based on the actual pupil size. When the pupil is constricted, it uses features from the scotopic image; when dilated, it uses features from the photopic image. This dynamic selection maintains tracking reliability across varying pupil sizes by adapting to the current physiological state.
Solution Approach 2:
The system changes the reference image parameters (selecting between scotopic and photopic images) based on the current pupil size. This parameter adaptation ensures that the most appropriate iris features are used for tracking under each condition, maintaining reliability while accommodating pupil size variations.
4Ease of operation
If the patient is kept awake during surgery, then comfort is improved, but eye movement tracking becomes more difficult
Solution Approach 1:
The system continuously captures images of the iris and pupil during surgery and provides real-time feedback on eye position and movement. This feedback mechanism allows the system to dynamically adjust and maintain accurate tracking even when the patient is awake and potentially moving, thereby preserving both patient comfort and tracking precision.
Solution Approach 2:
The system creates continuous optical copies (images) of the iris and pupil during surgery, allowing post-processing analysis of eye movements. This copying approach enables accurate measurement of eye movements even when the patient is awake, as the actual movements are captured and analyzed after the fact rather than requiring real-time control.
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 enhances the accuracy of eye alignment and tracking, reducing pupil center drift and improving the robustness of torsional tracking systems, resulting in more precise and effective laser eye surgical procedures.
Implementation Method 1
the computer system sends a command signal to variable light source 30 to direct the desired optical light output 32 to the eye, thereby inducing a pupillary response to affect the calculated change in pupil size
Implementation Method 2
Pupilometer 40 includes an optical sensor 42 and a processor 44 for determining changes in pupil size from optical information obtained by the optical sensor 42
Data Source
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AI summary
The present embodiments provides improved devices, systems, and methods for affecting changes in pupil sizes before a laser eye procedure and using those images for alignment before and/or during a diagnostic and/or treatment procedure of the eye, particularly during laser eye surgery procedures. The embodiments provide methods and systems for tracking pupil position and torsional cyclorotation of a patient's eye. In one exemplary embodiment, the present embodiments provides methods and software for registering a photopic image of an eye captured by a laser device to the eye images of the patient's eye using a scotopic image and a photopic image captured simultaneously during wavefront exam.