System and method for creating a customized anatomical model of an eye
View Patent ↗A system and method for creating a line recognition template that replicates an object is provided for use as a control reference during ophthalmic surgery on the object. Creation of the template first requires aligning a plurality of reference points along a central “z” axis, with anatomically measured lengths (Δ“z” n ) between adjacent reference points. Axially-symmetric surfaces can then be traced between selected, adjacent, reference points to create the template. For the present invention, the location of reference points, and the tracing of axially-symmetric surfaces, are based on a cross sectional image of the object for surgery. Preferably, the cross sectional image is obtained using Optical Coherence Tomography (OCT) techniques.
1. A method for creating a line recognition template to replicate an object which comprises the steps of:
aligning a plurality of reference points along a linear axis;
establishing a base reference axis, wherein the base reference axis is oriented in a “z” direction;
locating a base reference point on the base reference axis, wherein the base reference point is on an interface surface inside the object;
tracing a circular path on the interface surface, wherein the path is at a distance “r” from the base reference axis;
measuring variations in “z” along the path relative to a rotation angle (θ) about the base reference axis to identify a differential (δ z ), wherein δ z is measured between a z max at θ 1 and a z min at θ 2 ;
using δ z , θ 1 and θ 2 to measure an angle of tilt (φ) for the linear axis;
locating the reference points on the linear axis with anatomically measured contiguous lengths (Δ“z” n ) along the linear axis between sequentially adjacent reference points; and
tracing an axially-symmetric surface from selected reference points to create the template for replicating the object.
2. A method as recited in claim 1 wherein the locating step and the tracing step are based on a cross sectional image of the object.
3. A method as recited in claim 2 wherein the cross sectional image is obtained using techniques selected from a group comprising Optical Coherence Tomography (OCT), Scheimpflug, two-photon imaging and range finding.
4. A method as recited in claim 1 further comprises the steps of:
identifying a first axis, wherein the first axis is substantially parallel to the base reference axis and is at a distance “d 1 ” from the base reference axis;
locating a first reference point on the first axis, wherein the first reference point is located on the interface surface;
comparing the location of the first reference point with an expected location for the first reference point to determine a first differential (δ z ′);
identifying a second axis, wherein the second axis is substantially parallel to the base reference axis and is at a distance “d 2 ” from the base reference axis;
locating a second reference point on the second axis, wherein the second reference point is on the interface surface;
comparing the location of the second reference point with an expected location for the second reference point to determine a second differential (δ z ″); and
using δ z ′ and δ z ″ to measure verify the angle of tilt (φ).
5. A method as recited in claim 1 further comprising the step of using at least one selected reference point, together with the axis, as a base reference for controlling a movement of a laser beam focal point relative to the axially-symmetric surface.
6. A method as recited in claim 5 wherein a first reference point is located on a posterior surface of an anterior capsule and a second reference point is located on an anterior surface of a posterior capsule, and the focal point of the laser beam is moved between the anterior capsule and the posterior capsule to perform a capsulotomy.
7. A method for replicating anatomical features inside an eye which comprises the steps of:
identifying a “z” axis for the eye;
determining a tilt angle φ for the “z” axis relative to a base reference axis;
locating a base reference point on the base reference axis, wherein the base reference point is on an interface surface inside the object;
tracing a circular path on the interface surface, wherein the path is at a distance “r” from the base reference axis;
measuring variations along the base reference axis relative to a rotation angle (θ) about the base reference axis to identify a differential (δ), wherein δ is measured between a δ max at θ 1 and a δ min at θ 2 ;
using δ, θ 1 and θ 2 to measure the angle of tilt (φ);
creating a cross sectional image of the eye, wherein the image includes the “z” axis;
establishing a plurality of reference points aligned in sequence along the “z” axis in the cross sectional image, wherein each reference point is respectively located where a surface shown in the image intersects the “z” axis;
relating each reference point to a particularly identified anatomical surface in the image;
measuring a plurality of contiguous lengths (Δ“z” n ) along the “z” axis, wherein each length is individually measured between sequentially adjacent reference points; and
tracing an axially-symmetric surface from selected reference points to create a template replicating anatomical features inside the eye.
8. A method as recited in claim 7 wherein the creating step is accomplished using an Optical Coherence Tomography (OCT) device.
9. A method as recited in claim 7 further comprising the step of tracing a replica of an anatomical surface, wherein the replica is based on the location of a selected reference point and information in the image.
10. A method as recited in claim 7 further comprising the step of using at least one selected reference point, together with the “z” axis, as a base reference for controlling a movement of a laser beam focal point relative to an identified surface.
11. A method as recited in claim 10 wherein a first reference point is located on a posterior surface of an anterior capsule and a second reference point is located on an anterior surface of a posterior capsule, and the focal point of the laser beam is moved between the anterior capsule and the posterior capsule to perform a capsulotomy.
12. A non-transitory, computer-readable medium having executable instructions stored thereon for use with a computer to create a line recognition template to replicate an object, the instructions comprising: aligning a plurality of reference points in sequence along a linear axis; establishing a base reference axis oriented in a “z” direction and locating a base reference point on the base reference axis at an interface surface inside the object; tracing a circular path on the interface surface at a distance “r” from the base reference axis, and measuring variations in “z” along the path relative to a rotation angle (θ) about the base reference axis to identify a differential (δ z ), wherein δ z is measured between a z max at θ 1 and a z min at θ 2 and using δ z , θ 1 and θ 2 to measure an angle of tilt (φ) for the linear axis; locating the aligned reference points with measured contiguous lengths (Δ“z” n ) along the axis between sequentially adjacent reference points; and tracing an axially-symmetric surface from selected reference points for creating the template to replicate the object.
13. A medium as recited in claim 12 further comprising instructions for using at least one selected reference point, together with the axis, as a base reference for controlling a movement of a laser beam focal point relative to the axially-symmetric surface.
14. A medium as recited in claim 13 wherein a first reference point is located on a posterior surface of an anterior capsule and a second reference point is located on an anterior surface of a posterior capsule, and the focal point of the laser beam is moved between the anterior capsule and the posterior capsule to perform a capsulotomy.
15. A medium as recited in claim 12 wherein the program sections for locating and tracing are based on a cross sectional image of the object and the image is obtained using Optical Coherence Tomography (OCT) techniques.