Method for the model-based determination of the biometry of eyes

• US 9,649,024 B2
• Filed: 11/09/2011
• Issued: 05/16/2017
• Est. Priority Date: 11/12/2010
• Status: Active Grant

• Current Assignee: Carl Zeiss Meditec AG (Carl-Zeiss-Stiftung)
• Original Assignee: Carl Zeiss Meditec AG (Carl-Zeiss-Stiftung)
• Inventors: Hacker, Martin, Bajramovic, Ferid
• Primary Examiner(s): Sugarman, Scott J
• Assistant Examiner(s): BROOME, SHARRIEF I
• Application Number:
  US13/884,827
• Publication Number:
  US 20130301009A1
• Time in Patent Office: 2,015 Days
• Field of Search: 351205, 351208, 351212, 351246
• CPC Class Codes: A61B 3/1005 for measuring distances inside the eye, e.g. thickness of the cornea A61B3/11 takes precedence
• CPC Class Codes: A61B 3/102 for optical coherence tomography [OCT]
• CPC Class Codes: G01B 9/02063 by particular alignment of focus position, e.g. dynamic focussing in optical coherence tomography
• CPC Class Codes: G01B 9/02089 Displaying the signal, e.g. for user interaction
• CPC Class Codes: G01B 9/02091 Tomographic interferometers, e.g. based on optical coherence

Abstract

For the model-based determination of the biometry of eyes, the eye is illuminated by a light source via a scanning unit, the focus of the measuring light beam in the eye is moved or shifted laterally and/or axially via an adjusting device and the light fractions back-scattered by the boundary surfaces and from the tissue of the eye via an interferometer are detected by a sensor and relayed to a control and evaluation unit by which a parametric eye model which describes at least two boundary surfaces present in the eye is adapted to the scan or scans. The invention relates to the field of ophthalmology and serves in particular for the optical determination of the biometry of eyes by application of two-dimensional optical coherence tomography images. However, the method is not limited to the use of coherence tomography nor to the utilization of optical measurements.

Claims

1. A method of model-based determination of the biometry of eyes, based on optical coherence tomography (OCT), comprising

illuminating the eye by a light source via a scanning unit, wherein a focus of a measuring light beam in the eye is movable or switchable laterally and/or axially by application of an adjusting device;

detecting light components back-scattered from boundary surfaces and from tissue of the eye by a sensor via an interferometer;

relaying information from the sensor to a control and evaluation unit;

performing one or more scans having same or different scan patterns, same or different focus settings or a combination of the foregoing by application of the scanning unit, and receiving the scans by the sensor via the interferometer and relaying the one or more scans to the control and evaluation unit, which adapts a parametric eye model to create an adapted parametric eye model, which includes at least two boundary surfaces present in the eye;

deriving biometric measured values from the adapted parametric eye model; and

representing individual scans, all scans, the adapted parametric eye model or a combination thereof via a user interface.

2. The method according to claim 1, wherein the sensor receives B scans in the form of partial or whole eye scans via the interferometer.

3. The method according to claim 1, further comprising carrying out the adaptation of the parametric eye model to the scan or scans by the control and evaluation unit by comparing actual scans and simulated scans, by fitting functions or by a combination of comparing actual scans and simulated scans and by fitting functions.

4. The method according to claim 1, wherein the parametric eye model is two or three-dimensional, and model parameters of the adapted parametric eye model which describe the state of the eye are partially or completely configured.

5. The method according to claim 1, further comprising transmitting model parameters which are known or determined by other measuring methods via at least one of a measuring unit, an input unit or a data transmission unit which is additionally present.

6. The method according to claim 1, further wherein the control and evaluation unit compares simulated scans to actual OCT scans, and uses a determined deviation as a quality criterion of the model parameters or as a target function.

7. The method according to claim 1, further comprising taking into account via the control and evaluation unit, in at least one of the generation of simulated OCT scans, as part of the quality criterion, the target function or in the fitting of functions sources of error in at least one of signal generation, signal recording, or signal processing.

8. The method according to claim 7, further comprising optimizing the quality criterion or the target function by the control and evaluation unit, and adapting the parametric eye model to the scan or scans by the optimizing.

9. The method according to claim 7, further comprising using the partially or completely configurable model parameters in the generation of at least one of the simulated OCT scans, the quality criterion, the target function, the adaptation of the model to the actual scan or scans or in the fitting of functions, and wherein the partially or completely configurable model parameters directly influence the foregoing.

10. The method according to claim 1, further comprising using any given model for adapting the eye model to the scan or scans, and using the quality criterion not for optimization, but, rather, only for assessing the adaptation.

11. The method according to claim 1, further comprising, based on a measure of quality, rejecting the scan or scans and/or detected boundary surfaces and/or resulting biometric measurements as unusable, or requesting that the user to perform a manual assessment with the options of accepting the results, redetermining manually or redetermining semi-automatically, or rejection.

12. The method according to claim 1, further comprising representing the adapted parametric eye model on the user interface as an image, in the form of the relevant biometric measured values or both as an image and in the form of the relevant biometric measured values.