Intrastromal surgery correcting low order and high order aberrations of the eye
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
A61F-009/008
A61B-003/107
출원번호
US-0829027
(2007-07-26)
등록번호
US-9955867
(2018-05-01)
발명자
/ 주소
Lai, Shui T.
출원인 / 주소
Lai, Shui T.
대리인 / 주소
SF Bay Area Patents, LLC
인용정보
피인용 횟수 :
0인용 특허 :
11
초록▼
A method of correcting wavefront aberrations of an eye includes determining a high precision conventional intrastromal corneal ablation profile based on a direct removal of the intrastromal corneal tissue. An expanded ablation volume profile is constructed based on the direct tissue removal profile
A method of correcting wavefront aberrations of an eye includes determining a high precision conventional intrastromal corneal ablation profile based on a direct removal of the intrastromal corneal tissue. An expanded ablation volume profile is constructed based on the direct tissue removal profile and the expanded tissue volume is to be ablated instead to correct to the wavefront aberrations. The thickness of the ablated profile of a conventional ablation profile is expanded by an expansion factor (Nc−1)/(Nm−Nc), Nc is the index of refraction of the cornea and Nm the index of fill material. An expanded ablation volume filled with the fill material produces the effect of correcting wavefront aberrations as if a much smaller tissue volume were ablated without the fill material.
대표청구항▼
1. A method of dissecting a cornea tissue volume inside a cornea, comprising: (a) generating laser pulses that transmit through at least a portion of the cornea;(b) focusing the laser pulses inside the cornea and at a region of tissue to be dissected;(c) determining a three-dimensional cut pattern t
1. A method of dissecting a cornea tissue volume inside a cornea, comprising: (a) generating laser pulses that transmit through at least a portion of the cornea;(b) focusing the laser pulses inside the cornea and at a region of tissue to be dissected;(c) determining a three-dimensional cut pattern to dissect the tissue volume;(d) calculating a laser pulse deposit pattern using a single laser spot ablation profile;(e) dividing the laser spot deposit pattern into a series of ablation surfaces using one or more layers of laser spots, wherein the ablation surfaces comprise (i) at least one layer of contiguous laser spots, and(ii) at least one grid pattern of contiguous laser spots; and(f) directing the laser pulses to dissect the tissue volume in accordance with the calculating, wherein residual pieces of corneal tissue between adjacent layers of the contiguous laser spots are not directly ablated and remain after the directing of the laser pulses in accordance with the calculating, wherein a reduction in number of pulses used compared with fully ablating the tissue volume serves to reduce heating of the cornea during laser surgery, and(g) removing the residual pieces from inside the cornea. 2. The method of claim 1, further comprising: (h) ordering the ablation surfaces starting from the farthest to the closest plane to the anterior cornea surface; and(i) directing the laser to ablate tissue in accordance with the farthest ablation surface; and(j) continuing the tissue ablation process to the next ablation surface in the sequence, and repeating until the tissue volume is dissected in accordance with the cut pattern. 3. The method claim of 1, wherein the calculating comprises overlapping focused laser pulses between 0.7 to 1.8 of the laser spot radius within the region of tissue to be dissected. 4. One or more non-transitory computer readable media having program code embodied therein for programming one or more processors to control a method of dissecting a cornea tissue volume inside a cornea according to claim 1. 5. A processor-implemented method of reducing heating of the cornea during an intrastromal laser surgery, comprising: (a) determining a corneal tissue volume profile to be ablated;(b) determining a cutting pattern for the tissue volume comprising a series of cutting surfaces, wherein adjacent surfaces of cut are positioned to be separated by greater than one (1) times the diameter of an ablation spot created by a single shot of laser pulses; and(c) converting the cut pattern into executable steps in a computerized program for controlling a laser beam to cut the tissue volume; and(d) directing the laser beam to cut the tissue volume into a plurality of pieces according to the cutting pattern, and(e) wherein the cutting pattern includes intersecting cutting surfaces and spacings between adjacent surfaces such that residual pieces of corneal tissue remain within the tissue volume after directing the laser beam to cut the tissue according to the cutting pattern, and the method further comprises removing the multiple residual pieces; and(f) wherein a significant reduction in number of laser pulses used compared with fully ablating the tissue volume serves to reduce heating of the cornea during a laser surgery. 6. The method of claim 5, wherein dissected tissue includes tissue to be absorbed into the surrounding tissue. 7. The method of claim 5, wherein two or more adjacent surfaces comprises adjacent planes of cut. 8. One or more non-transitory computer readable media having program code embodied therein for programming one or more processors to control a method of reducing heating of the cornea during an intrastromal laser surgery according to claim 5. 9. The method of claim 5, wherein the removing the multiple sub-volumes includes suctioning said tissue from the cornea. 10. The method of claim 9, further comprising inserting a cannula and applying suction to the cannula. 11. The method of claim 5, further comprising: (g) determining an expanded tissue tissue volume based on an expansion factor (Nc−1)/(Nm−Nc), wherein Nc and Nm are indices of refraction of cornea tissue and a fill material, respectively;(h) removing an expanded volume of stromal tissue according to (g); and(i) filling a stroma space vacated by removed cornea tissue with the fill material. 12. The method of claim 11, further comprising applying a monitoring measurement to the eye, and terminating the filling of the stroma space when the desired corneal profile is attained as determined by the monitoring measurement. 13. A method of correcting wavefront aberrations of an eye, comprising: (a) determining a corneal ablation tissue volume profile for an eye in three dimensions for correcting wavefront error upon removal of corneal tissue in accordance with said determined profile,(b) selecting a fill material to be used to fill space within the tissue volume upon said removal of corneal tissue,(c) determining an expansion factor: (Nc−1)/(Nm−Nc), wherein Nc and Nm are indices of refraction of cornea tissue and the fill material, respectively;(d) determining an expanded ablation volume in the cornea, wherein the expanded ablation volume comprises the determined profile with its thickness multiplied by the expansion factor in (c),(e) ablating cornea tissue according to the determined expanded ablation volume; and(f) filling a stroma space vacated by ablated cornea tissue of the expanded ablation volume with the fill material. 14. The method of claim 13, wherein the expanding of the ablation volume is along a direction of an optical path traversing the cornea. 15. The method of claim 13, further comprising determining an expansion ablation volume comprising (i) converting an OPD wavefront error profile of the eye in air to an ablation cornea tissue volume using an index of refraction of the cornea, to account for an optical path length in cornea versus that in air, and(ii) converting the ablation cornea tissue volume to an expanded fill tissue volume to be filled by the selected fill material, wherein the converting into fill tissue volume includes taking into account of the index of refraction of the selected fill material versus that in cornea. 16. One or more non-transitory computer readable media having program code embodied therein for programming one or more processors to control a method of correcting wavefront aberrations of an eye according to claim 13. 17. The method of claim 13, wherein aberrations of the eye to be corrected comprise: (a) one or more low order aberrations including sphere or astigmatism, or both; or(b) one or more high order aberrations that are describable using Zernike polynomials of third and higher orders; or(c) combinations of (a) and (b). 18. The method of claim 13, wherein ablating cornea tissue comprises generating an excision line path. 19. The method of claim 18, wherein generating an excision line path comprises: (i) generating a beam of laser pulses with pulse duration between 10 and 2000 femtoseconds,(ii) focusing the beam to an interaction point inside the cornea such that the laser pulses generate ablation spots with diameters ranging from 1 to 20 microns,(iii) directing the beam by a computerized laser control unit, overlapping the ablation spots generated by the laser pulses by positioning the laser focus location at a separation in the range of 0.7 to 1.8 times an ablation spot radius. 20. The method of claim 18, wherein ablating cornea tissue further comprises controlling the generation of at least one excision line, and positioning said at least one excision line to overlap to another excision line to generate an excision plane, wherein an excised line separation ranges from 0.7 to 1.8 times an ablation spot radius. 21. The method of claim 13, further comprising applying a monitoring measurement to the eye, and terminating the filling of the stroma space when the desired corneal profile is attained as determined by the monitoring measurement. 22. One or more non-transitory computer readable media having program code embodied therein for programming one or more processors to control a method of monitoring the filling of the fill material according to claim 21. 23. A method as in claim 13, further comprising: (a) creating an entry cut to an eye to provide for an entry point;(b) exising a channel, and connecting an entry cut opening to the ablated tissue volume;(c) inserting a cannula through the entry cut to the ablated volume;(d) injecting a fill material into the ablated tissue volume; and(e) applying a monitoring measurement to the eye, and terminating the filling of the stroma space when the desired corneal profile is attained as determined by the monitoring measurement. 24. One or more non-transitory computer readable media having program code embodied therein for programming one or more processors to control a method of generating and filling an ablated tissue volume in a stroma of an eye according to claim 23.
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