US 12,329,514 B2
Methods for dynamic position measurement of ocular structures using purkinje reflection spots
Daniel R. Neal, Albuquerque, NM (US); and R James Copland, Albuquerque, NM (US)
Assigned to WaveFront Dynamics, Inc., Albuquerque, NM (US)
Filed by Wavefront Dynamics, Inc., Albuquerque, NM (US)
Filed on Jan. 9, 2021, as Appl. No. 17/145,335.
Claims priority of provisional application 63/085,391, filed on Sep. 30, 2020.
Claims priority of provisional application 62/959,127, filed on Jan. 9, 2020.
Prior Publication US 2021/0212601 A1, Jul. 15, 2021
Int. Cl. A61B 3/113 (2006.01); A61B 3/02 (2006.01); A61B 3/10 (2006.01); A61B 3/12 (2006.01); A61B 3/14 (2006.01); A61B 5/00 (2006.01); A61B 5/11 (2006.01)
CPC A61B 5/1128 (2013.01) [A61B 3/113 (2013.01); A61B 3/14 (2013.01); A61B 5/0059 (2013.01); A61B 3/102 (2013.01)] 24 Claims
OG exemplary drawing
 
1. A method of determining an XYZ position and tip/tilt orientation of an optical structure in a patient's eye by using an optical instrument, wherein the method comprises:
(a) providing an optical instrument with a main optical axis, a camera aligned with the main optical axis, and a plurality of front light sources disposed around the main optical axis;
(b) illuminating the patient's eye with a first front light source; then
(c) capturing, with the camera, a first image of the patient's eye, wherein the first image comprises one or more first front Purkinje reflection spots from the optical structure; then
(d) turning off the first front light source; then
(e) illuminating the patient's eye with a second front light source, wherein the second front light source is offset from the first front light source; then
(f) capturing, with the camera, a second image of the patient's eye, wherein the second image comprises one or more second front Purkinje reflection spots from the optical structure;
then
(g) comparing the first image to the second image, and associating the one or more first and second front Purkinje reflection spots with one or more surfaces of the optical structure;
(h) measuring, using the first and second images, one or more positions of the one or more first and second front Purkinje reflection spots;
(i) calculating an XYZ position and/or tip/tilt angles of the optical structure by using the one or more positions of the one or more first and second front Purkinje reflection spots;
(j) illuminating the patient's eye with a first rear light source that is located at a rear Z-axis position along the main optical axis, wherein the first rear light source is located farther away from the patient's eye than the first front light source;
(k) generating one or more first rear Purkinje reflection spots on the patient's eye; then (l) turning off the first rear light source; then
(m) illuminating the patient's eye with a second rear light source that is located at the rear Z-axis position;
(n) generating one or more second rear Purkinje reflection spots on the patient's eye;
(o) measuring one or more first positions of the one or more first rear Purkinje reflection spots;
(p) measuring one or more second positions of the one or more second rear Purkinje reflection spots;
(q) comparing the one or more first positions to the one or more second positions;
(r) calculating a front position of a front surface of the optical structure; and
(s) calculating a rear position along a Z-axis of a rear surface of the optical structure;
wherein the first rear light source is offset from the second rear light source;
wherein the Z-axis coincides with the main optical axis of the optical instrument;
wherein light emitted by the first and second front light sources takes a single pass though the optical instrument;
wherein single-pass Purkinje images generated by the first and second front light sources are responsive to both movement and curvature of the optical structure;
wherein light emitted by the first and second rear light sources takes a double-pass though the optical instrument;
wherein double-pass Purkinje images generated by the first and second rear light sources are responsive only to the curvature of the optical structure and are not responsive to changes in an axial path distance along the main optical axis; and
wherein the method further comprises:
(t) determining a Z-axis distance from a patient's cornea to a front objective lens of the optical instrument; and
(u) determining a curvature of the optical structure by comparing the single-pass Purkinje images to the double-pass Purkinje images.