Confocal Optical Detection for Ophthalmic Docking Contact Loss
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Solution Overview
Problem
Current ophthalmic laser systems lack effective real-time detection of contact loss between the eye's surface and the patient interface lens, leading to potential eye movement and tissue contact issues during refractive surgery, which can result in ineffective or unintended surgical cuts and permanent injury.
Innovation Solution
A confocal optical system that continuously monitors the intensity of a laser beam reflected from the patient interface device, using a pinhole and photodetector to detect changes in contact state between the device and the eye tissue, allowing for real-time feedback and responsive actions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If no contact detection system is used, then the device complexity is reduced, but the reliability of surgical procedure is compromised due to undetected eye movement and tissue contact loss
Solution Approach 1:
The optical detection system serves multiple functions: it monitors both tissue contact status and eye position simultaneously using the same optical components, eliminating the need for separate detection systems while enhancing surgical reliability
Solution Approach 2:
The patent introduces an optical intermediary system that detects tissue contact through light reflection changes without physically contacting the eye or interfering with the surgical procedure, thereby maintaining reliability without adding mechanical complexity
2Object-affected harmful factors
If real-time contact detection is implemented, then the safety control is improved, but the device complexity increases due to additional sensors and monitoring systems
Solution Approach 1:
The system continuously monitors optical signals from the tissue interface and provides real-time feedback to the control system, enabling immediate detection of contact loss and automatic pausing of laser treatment to prevent surgical errors
Solution Approach 2:
The patent replaces complex mechanical contact sensors with an optical detection system that uses light reflection properties to detect tissue contact status, reducing mechanical complexity while improving safety response time
3Measurement precision
If the laser beam focus is continuously monitored for contact status, then the measurement precision is improved, but the use of energy increases due to continuous optical monitoring
Solution Approach 1:
The optical monitoring system operates periodically at optimized intervals rather than continuously, maintaining sufficient measurement precision for safety while reducing energy consumption by activating monitoring only when contact status changes are expected
Solution Approach 2:
The system uses minimal optical energy sufficient for detection purposes only, rather than full laser power, by directing a low-energy probe beam for contact monitoring separate from the therapeutic laser beam
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
Enables sensitive and immediate detection of tissue contact loss, preventing surgical complications by pausing or terminating the treatment when anomalies occur, and providing robust applanation detection for successful docking.
Implementation Method 1
monitors the intensity of a laser beam reflected from the patient interface device
Implementation Method 2
A confocal optical system that continuously monitors the intensity of a laser beam reflected from the patient interface device, using a pinhole and photodetector to detect changes in contact state
Implementation Method 3
using a pinhole and photodetector to detect changes in contact state
Data Source
Figure 1
Figure 2~3
Figure 4A~6B
AI summary
An ophthalmic laser surgical system uses a confocal detector assembly to continuously detect a confocal signal during laser treatment, and based on the confocal signal, detects in real time a loss of tissue contact with the patient interface (PI) output surface. The detection is partly based on the change of reflectivity at the PI output surface when the optical interface changes from a lens-tissue interface to a lens-air interface. The behavior of the confocal signal upon loss of tissue contact is dependent on the treatment laser scan pattern being performed at the time of tissue contact loss. Thus, different confocal signal analysis algorithms are applied to detect tissue contact loss during different scans, such as the bed cut and side cut for a corneal flap. The real time confocal signal may also be used during eye docking to detect the establishment of tissue contact with the PI output surface.