Corneal Lenticule Edge Geometry for Stable Hyperopia Correction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional LASIK methods for correcting hyperopia using femtosecond lenticule extraction (FLEx) face challenges with postoperative regression due to the detachment and reapplication of corneal lamella, leading to undesirable side effects and unpredictable healing processes.

Innovation Solution

A treatment apparatus and method that isolates a lenticular volume in the cornea with specific edge and face configurations, including a wide transition zone outside the optically effective region, and an edge thickness of 5-10 μm, minimizing regression by ensuring smooth integration and reducing particle detachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional LASIK methods use femtosecond lenticule extraction (FLEx) to correct hyperopia, then the corneal lamella can be detached and reapplication, but postoperative regression occurs due to undesirable side effects and unpredictable healing processes

Engineering Contradiction:

Improvepredictability of healing processVSAvoidpostoperative regression

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The corneal cut is divided into multiple distinct zones with different geometries: a first cut zone forming the anterior face, a second cut zone forming the posterior face, and a third cut zone forming the edge face. This segmentation allows each zone to be optimized for its specific function, reducing unpredictable healing and regression.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the corneal cut are given different properties: the edge face is designed with a width greater than the perpendicular distance to provide a wide transition zone for stability, while the anterior and posterior faces have specific orientations for optimal healing. This local differentiation of cut properties reduces regression and improves predictability.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If the corneal cut is made with narrow edges to minimize tissue removal, then the lenticular volume can be precisely isolated, but particle detachment occurs leading to regression

Engineering Contradiction:

Improveprecision of lenticular volume isolationVSAvoidparticle detachment

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The edge face is designed as a wide transition zone connecting the anterior and posterior faces, providing structural support and preventing particle detachment. This transition zone acts as a reinforcing structure that maintains edge integrity while allowing precise lenticular volume isolation.

Inventive Principle:

Principle #30Flexible shells and thin films

3Productivity

If the corneal cut has steep edges to efficiently remove lenticular volume, then the surgical procedure is faster, but the edge structure is unstable leading to regression

Engineering Contradiction:

Improveefficiency of lenticular volume removalVSAvoidstability of edge structure

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The edge face is designed with a curved transition zone rather than a sharp angular edge. This curvature provides a stable geometric structure that resists particle detachment while maintaining efficient lenticular volume removal. The wide transition zone creates a more stable edge structure compared to steep cuts.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 solution effectively reduces postoperative regression by providing a stable edge structure that facilitates predictable healing and secure removal of the lenticular volume, maintaining the desired refractive correction.

Implementation Method 1

separates corneal tissue by applying laser radiation... a lenticular volume is thus isolated in the cornea

Methodology Applied

Scientific EffectOptical breakdown: Laser Ablation

Data Source

PatentUS12433789B2Treatment apparatus for operatively correcting defective vision of an eye, method for generating control data therefor, and method for operatively correcting defective vision of an eye

Publication Date: 2025.10.07 CARL ZEISS MEDITEC AG

AI summary

A treatment device for the surgical correction of hyperopia in the eye comprising a laser device controlled by a control device. The laser device separating corneal tissue by applying laser radiation. The control device controls the laser device for emitting the laser radiation into the cornea such that a lenticule-shaped volume is isolated. Removal thereof effects the desired correction. The control device predefines the volume such that a posterior surface and an anterior surface are connected via an edge surface that has a width in projection along the visual axis that is wider than the one which a straight line in the same projection, that is perpendicular at the edge of the posterior or the anterior surface would have relative to the associated surface and connects the anterior surface to the posterior surface or to the perceived extension thereof.