LIOB Corneal Reshaping Without Tissue Removal

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Solution Overview

Problem

Current methods for altering the optical properties of transparent resilient materials, such as the cornea, face challenges in reshaping these materials without material removal or significant tissue disruption, particularly in responding to external forces like intraocular pressure.

Innovation Solution

The system employs Laser Induced Optical Breakdown (LIOB) to create specific patterns of cuts and layers within the stromal tissue of the cornea, redistributing bio-mechanical forces and reshaping the material without removing tissue, using a femtosecond laser to generate precise cuts and layers that alter the material's configuration and optical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional refractive surgery methods are used to reshape the cornea, then refractive imperfections can be corrected, but significant tissue removal or disruption is required

Engineering Contradiction:

Improverefractive correction precisionVSAvoidcorneal tissue loss

Core Design Contradiction:

Manufacturing precisionVSLoss of substance

Solution Approach 1:

The corneal stroma is segmented into multiple lamellae layers. The laser creates controlled disruptions within specific lamellae rather than removing tissue from the entire cornea. This segmentation allows selective modification of stress distribution in targeted regions while preserving the overall structural integrity and bulk tissue of the cornea.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention applies local quality changes by creating laser-induced disruptions only in specific regions and depths of the corneal stroma. The laser parameters (energy, duration, focal depth) are locally adjusted to create precise patterns within individual lamellae or specific zones, allowing customized stress redistribution without affecting the entire corneal structure uniformly.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If laser energy is increased to achieve deeper penetration and more effective tissue modification, then refractive correction effectiveness improves, but tissue damage and loss increase

Engineering Contradiction:

Improvestromal modification precisionVSAvoidtissue damage

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The laser operates in periodic pulsed mode rather than continuous wave. Short-duration pulses (femtosecond to picosecond range) are delivered at controlled intervals, allowing the tissue to cool and recover between pulses. This periodic action enables cumulative tissue modification through repeated low-energy exposures without causing thermal damage or excessive tissue loss that would result from continuous high-energy exposure.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The invention utilizes parameter changes by varying laser characteristics (pulse duration, energy level, repetition rate, focal depth) to achieve different modification depths and patterns within the stroma. By adjusting these parameters, the laser can selectively affect specific lamellae at different depths without requiring high energy levels that would cause collateral tissue damage.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If the cornea is reshaped to correct refractive errors, then optical properties are improved, but the structural integrity and strength of the cornea may be compromised

Engineering Contradiction:

Improvecorneal shape controlVSAvoidcorneal structural strength

Core Design Contradiction:

Manufacturing precisionVSStrength

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The laser-induced disruptions within the stromal lamellae act as predetermined stress redistribution zones that cushion and redirect mechanical forces. These controlled weak points are strategically created to alter force transmission pathways in a way that maintains overall corneal strength while enabling shape modification for refractive correction.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 allows for customized refractive corrections by reshaping the cornea, effectively addressing refractive imperfections like presbyopia, myopia, hyperopia, and astigmatism, while maintaining the integrity of the cornea and altering its optical properties without significant tissue loss.

Implementation Method 1

The system employs Laser Induced Optical Breakdown (LIOB) to create specific patterns of cuts and layers within the stromal tissue of the cornea

Methodology Applied

Scientific EffectLaser Induced Optical Breakdown (LIOB): Laser Ablation

Data Source

PatentEP2555701B1Systems for altering the optical properties of a material

Publication Date: 2020.12.23 TECHNOLAS PERFECT VISION

Figure 1~5C
Figure 6~9D
Figure 10~11B

AI summary

A system for changing the configuration of a transparent, resilient material, for the purpose of altering its optical properties, requires obtaining a topology for the material. The obtained data is then used to create a computer program for operating a laser unit. In accordance with the program, the laser unit creates incisions within a defined operational volume, inside the material, to weaken the material (i.e. change its internal stress distributions). Specifically, the incisions are made on predetermined surfaces (e.g. cylindrical surfaces) in the operational volume by Laser Induced Optical Breakdown (LIOB). As a consequence of the incisions, the material undergoes the desired configurational change in response to external forces applied on the material.