Treatment apparatus for surgical correction of defective eyesight, method of generating control data therefore, and method for surgical correction of defective eyesight

Patent metadata

Field	Value
Publication number	US-12496223-B2
Application number	US-202117458092-A
Country	US
Kind code	B2
Filing date	Aug 26, 2021
Priority date	Nov 10, 2006
Publication date	Dec 16, 2025
Grant date	Dec 16, 2025

Abstract

A treatment method and apparatus for surgical correction of defective-eyesight in an eye of a patient, wherein a laser device is controlled by a control device, said laser device separating corneal tissue by irradiation of laser radiation to isolate a volume located within a cornea, wherein the control device controls the laser device to focus the laser radiation, by providing target points located within the cornea, into the cornea, wherein the control device, when providing the target points, allows for focus position errors which lead to a deviation between the predetermined position and the actual position of the target points when focusing the laser radiation, by pre-offsets depending on the positions of the respective target points to compensate for said focus position errors.

First claim

The invention claimed is:

1 . A method for laser based surgical correction of an eyesight defect in a patient's eye, wherein the eye comprises a cornea having an anterior corneal surface and corneal tissue located below the anterior corneal surface, the method comprising:
applying a spherical contact glass to the cornea thereby deforming the anterior corneal surface to conform to a spherical shape of the spherical contact glass; creating a three dimensional (3D) cut within the cornea, the 3D cut confining a volume located within the cornea, isolating the volume within the cornea, and making the volume extractable from the interior of the cornea, wherein the volume is sized such that removal of the volume from the corneal tissue below the anterior corneal surface changes a shape of the anterior corneal surface such that the eyesight defect is corrected or reduced, wherein creating the 3D cut comprises emitting pulsed laser radiation from a laser device and focusing the pulsed laser radiation to a three-dimensional pattern of target points in the cornea, wherein the target points are located in a 3D surface defining the 3D cut, wherein creating the 3D cut further comprises forming the 3D surface with two surface parts including an anterior surface part and a posterior surface part, further forming the anterior surface part to be a paraboloid that is cut while the anterior corneal surface is deformed to be spherical by application of the spherical contact glass and the wherein the posterior surface part does not have a constant distance from the anterior corneal surface.

2 . The method as claimed in claim 1 , wherein creating the 3D cut further comprises forming the 3D surface with a lateral side cut part connecting the volume with the anterior corneal surface, and wherein the method further comprises removing the volume from the corneal tissue through the lateral side cut part.

3 . The method as claimed in claim 1 , further comprising
determining measurement data on parameters of the eye and defective-eyesight data on the eyesight defect, defining the volume on basis of the measurement data and the defective-eyesight data, determining the 3D surface to confine the defined volume within the cornea, determining the three-dimensional pattern of target points located in the 3D surface, and generating a control data set which relates to the three-dimensional pattern for control of a laser device providing the pulsed laser radiation.

4 . The method as claimed in claim 3 , further comprising providing a planning device remote from the laser device and performing the steps of claim 2 in the planning device and transmitting the control data set to a treatment apparatus comprising the laser device, and blocking operating of the laser device until a valid control data set is present at the laser device.

5 . The method as claimed in claim 3 , wherein the defective-eyesight data comprise a refractive power B BR of spectacles suitable for correction of eyesight defect, as well as a distance, at which the spectacles having the refractive power B BR should be located anterior of a vertex of the anterior corneal surface to achieve the correction of eyesight defect by use of the spectacles.

6 . The method as claimed in claim 3 , wherein the volume is defined such that the anterior corneal surface assumes a radius of curvature R cv * after removal of the volume, said radius satisfying the following equation:
R cv *=1/((1/ R cv )+ B BR /(( n c −1)(1− d HS ·B BR )))+ F,
wherein R cv is the radius of curvature of the anterior corneal surface prior to removal of the volume n c is a refractive index of the corneal tissue and F is a correction value,
wherein optionally F=(1−1/n c )·(d c *−d c ) holds true, wherein d c or d c * is a thickness of the cornea before or after removal of the volume, respectively, and radius R cv * is computed in an iterative manner by deriving a quantity (d c *−d c ) from the difference R cv *−R cv ) during each iteration step, and applying a corresponding result for a change in thickness to calculate R cv * in a next iteration step.

7 . The method as claimed in claim 1 , wherein focusing the pulsed laser radiation to the three-dimensional pattern of target points with the laser device comprises shifting a focus of the pulsed laser radiation along a path over the pattern of target points, with pulses of the pulsed laser radiation being emitting into the cornea at points located on the path and also between the target points.

8 . The method as claimed in claim 1 , wherein focusing the pulsed laser radiation to the three-dimensional pattern of target points with the laser device comprises shifting a focus of the pulsed laser radiation along a path over the pattern of target points, wherein in the posterior surface part the path is an elliptical spiral.

9 . The method as claimed in claim 1 , further comprising pressing a spherical contact surface of a contact glass onto the anterior corneal surface prior to creating the 3D cut, wherein focusing the pulsed laser radiation to the three-dimensional pattern of target points laser device comprises shifting a focus of the pulsed laser radiation along a path over the pattern of target points, wherein in the anterior surface part the path is a paraboloid spiral.

10 . A method for preparing control data for laser based surgical correction of an eyesight defect in a patient's eye, wherein the eye comprises a cornea having an anterior corneal surface and corneal tissue located below the anterior corneal surface, the method comprising:
determining measurement data on parameters of the eye and defective-eyesight data on the eyesight defect, defining a volume on a basis of the measurement data and the defective-eyesight data, wherein the volume is sized such that removal of the volume from the corneal tissue below the anterior corneal surface changes a shape of the anterior corneal surface such that the eyesight defect is corrected or reduced, determining a three dimensional (3D) surface to confine the defined volume within the cornea, wherein the 3D surface comprises two surface parts including an anterior surface part and a posterior surface part and determining the control data for the treatment apparatus for the anterior surface part accounting for a spherical contact glass deforming the anterior corneal surface to become spherical wherein the anterior surface part is a paraboloid that is cut while the anterior corneal surface is deformed to be spherical by application of the spherical contact glass and wherein the posterior surface part does not have a constant distance from the anterior corneal surface, determining a three-dimensional pattern of target points located in the 3D surface, wherein the 3D surface defines a 3D cut within the cornea, the 3D cut confining the volume located within the cornea, isolating the volume within the cornea, and making the volume extractable from the interior of the cornea, and generating a control data set which relates to the three-dimensional pattern for control of a laser device providing the pulsed laser radiation to create the 3d cut.

11 . The method as claimed in claim 10 , wherein determining the 3D surface comprises forming the 3D surface with a lateral side cut part connecting the volume with the anterior corneal surface that facilitates removing the volume from the corneal tissue through the lateral side cut part.

12 . The method as claimed in claim 10 , further comprising providing a planning station remote from the laser device and performing the steps of claim 9 in the planning station and transmitting the control data set to a tre

Assignees

• Zeiss Carl Meditec Ag

Inventors

• Wiechmann Martin
• Bergt Michael
• Bischoff Mark
• Sticker Markus
• Stobrawa Gregor

Classifications

• A61F2009/00851

  Optical coherence topography [OCT] · CPC title

• A61F2009/00848

  based on wavefront · CPC title

• A61F2009/00878

  Planning · CPC title

• A61B34/10

  Computer-aided planning, simulation or modelling of surgical operations · CPC title

• A61F2009/00897

  Scanning mechanisms or algorithms · CPC title