Dynamic Eye Fixation System for Laser Ophthalmic Surgery

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Solution Overview

Problem

Current eye fixation systems in laser ophthalmic surgery are inadequate as they rely on rigid interfaces and fixed light spots, leading to eye movement instability during procedures like cataract surgery, where lens fragmentation disrupts the patient's ability to focus, causing the eye to wander out of the target range, necessitating frequent pauses in the surgery.

Innovation Solution

A dynamic fixation system that uses a visual fixation system with adjustable and repositionable target images, projected by laser delivery optics, allowing for real-time alignment adjustments based on eye movements and refractive changes, enabling continuous focus during ophthalmic procedures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixed light spot fixation system is used, then the patient can initially focus on the target, but the eye will wander when lens fragmentation occurs during cataract surgery

Engineering Contradiction:

Improveeye fixation stabilityVSAvoidresponse to refractive changes

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The fixation target is transformed from a static light spot to a dynamic image that can be repositioned and refocused. The system dynamically adjusts the target's position and focal depth in response to eye movements and refractive changes during surgery, maintaining reliable fixation throughout the procedure.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes multiple parameters of the fixation target including its position, focal depth, and optical characteristics. By adjusting these parameters in real-time, the system maintains effective fixation despite changes in the patient's refractive state during lens fragmentation.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If a rigid patient interface is used for eye tracking, then the laser can be delivered, but the patient loses familiarity with surroundings and cannot hold the eye steady

Engineering Contradiction:

Improveeye position stabilityVSAvoidpatient cooperation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The rigid mechanical patient interface is replaced with an optical system that projects images through the cornea. This substitution eliminates the need for physical contact while maintaining eye stabilization, allowing patients to remain aware of their surroundings and cooperate more effectively.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system creates optical copies of fixation targets that are projected through the cornea rather than requiring physical docking. This allows the patient to see and focus on virtual images without the discomfort and disorientation caused by rigid interfaces.

Inventive Principle:

Principle #26Copying

3Measurement precision

If the fixation target is fixed in the central region, then visual acuity is maximized, but the eye must be held perfectly steady within a 5 degree range

Engineering Contradiction:

Improvevisual acuityVSAvoideye tracking control range

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The fixation target system dynamically tracks and compensates for eye movements, allowing the target to move with the eye while maintaining central fixation. This reduces the strictness of the 5-degree control range requirement while preserving visual acuity.

Inventive Principle:

Principle #15Dynamics

4Reliability

If frequent pauses are taken to re-center the eye, then the laser procedure can continue, but the overall procedure time increases

Engineering Contradiction:

Improvetarget acquisitionVSAvoidsurgical throughput

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The dynamic fixation system maintains continuous effective fixation throughout the procedure by automatically adjusting the target in real-time. This eliminates the need for intermittent pauses to re-acquire the target, allowing the laser procedure to proceed continuously and improving surgical throughput.

Inventive Principle:

Principle #20Continuity of useful action

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 dynamic fixation system enhances eye alignment and stability throughout ophthalmic procedures, reducing the need for frequent pauses by dynamically adjusting target images in response to eye movements and refractive changes, ensuring consistent visualization and concentration on the target.

Implementation Method 1

a laser delivery system for delivering a pulsed laser beam to photoalter an eye

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

a visual fixation system that projects target images onto a patient's eye

Methodology Applied

Scientific EffectLight emission: Light

Data Source

PatentUS9155658B2Systems and methods for dynamic patient fixation system

Publication Date: 2015.10.13 AMO DEVELOPMENT LLC

AI summary

The field of the invention relates to systems and methods for ophthalmic laser procedure and, more particularly, to systems and methods for dynamic fixation used in the fixation of the eye(s) of a patient during laser-assisted ophthalmic surgery and/or ophthalmic diagnostic and measurement systems where visualization and concentration on a target are desired. The invention generally enhances the alignment between the eye and a laser beam of a laser eye surgery system using visual fixation system and laser delivery optics. The visual fixation system allows a patient's eye(s) to be accurately focused at one or more fixation targets.