US 7,008,415 B2 · Generating scanning spot locations for laser eye surgery

Abstract

Scanning spot locations are generated for ablating tissue using a scanning laser beam over a treatment region by taking a target function representing a desired lens profile of ablation with a basis function representing a treatment profile produced by overlapping scanning spots in a particular treatment pattern. In some embodiments, the basis function is a two-dimensional function representing a two-dimensional section of a three-dimensional treatment profile, which has symmetry with respect to the two-dimensional section extending along the treatment pattern. For example, the treatment pattern is generally straight for myopic and hyperopic cylinders, and is generally circular for myopia and hyperopia. The fit produces ablation depths for discrete scanning spots, which are used to calculate the number of pulses at each reference position along the two-dimensional section. The pulses are distributed along the treatment pattern to produce the desired overlapping effect.

Claims26

Dependent claims

A method for fitting a three-dimensional target profile, the method comprising:

providing a two-dimensional user-specified basis function including overlapping portions that are disposed at a plurality of locations and overlap with one another to represent a three-dimensional profile which has symmetry with respect to a two-dimensional section extending along a treatment pattern;
and
fitting the three-dimensional target profile with the two-dimensional user-specified basis function to obtain a distribution of the overlapping portions that are disposed at the plurality of locations, each overlapping portion representing a two-dimensional treatment portion to be applied to a tissue and combined with other overlapping portions to achieve the three-dimensional target profile for treatment of the tissue according to the distribution obtained from the fitting.

A method for fitting a three-dimensional target profile, the method comprising:

providing a two-dimensional basis function including overlapping portions to represent a three-dimensional profile which has symmetry with respect to a two-dimensional section extending along a treatment pattern;
and
fitting the three-dimensional target profile with the two-dimensional basis function to obtain a distribution of the overlapping portions;
wherein the basis function includes M discrete basis functions representing M overlapping portions;
wherein the M discrete basis functions represent M overlapping portions across a treatment zone length representing the length across a generally two-dimensional section which is oriented normal across a generally straight treatment pattern or which is oriented radially across a generally circular treatment pattern.

2 more elements

A method for fitting a three-dimensional target profile, the method comprising:

providing a two-dimensional basis function including overlapping portions to represent a three-dimensional profile which has symmetry with respect to a two-dimensional section extending along a treatment pattern;
and
fitting the three-dimensional target profile with the two-dimensional basis function to obtain a distribution of the overlapping portions;
wherein the target function is:
(A) for myopia and myopic cylinder,
f
⁡
(
x
j
)
=
R
1
2
-
x
j
2
-
(
R
1
⁡
(
n
-
1
)
n
-
1
+
R
1
⁢
D
)
-
x
j
2
+
C
or
(B) for hyperopia and hyperopic cylinder,
f
⁡
(
x
j
)
=
R
1
-
R
1
⁡
(
n
-
1
)
n
-
1
+
R
1
⁢
D
-
R
1
2
-
x
j
2
+
(
R
1
⁡
(
n
-
1
)
n
-
1
+
R
1
⁢
D
)
-
x
j
2
or
(C) for phototherapeutic keratectomy,
f(xj)=d;
where
0≦xj≦(L−shift);
j=0, 1, . . . , N−1;
C
=
R
1
2
-
s
2
/
4
+
(
R
1
⁡
(
n
-
1
)
n
-
1
+
R
1
⁢
D
)
-
s
2
4
;
xj is an x-coordinate measured from an optical axis of the cornea of the jth evaluation point for the center of the overlapping portion;
s is the diameter of the overlapping portion;
R1 is the anterior radius of curvature of the cornea in meters;
R2 is the final anterior radius of curvature of the cornea in meters;
n =1.377 is the index of refraction of the cornea;
D is the lens power of the overlapping portion in diopters;
L is the treatment zone length representing the length across a generally uniform section which is oriented normal across a generally straight treatment pattern for myopic or hyperopic cylinders, or which is oriented radially across a generally circular treatment pattern for myopia or hyperopia;
shift is the amount of emphasis shift;
and
d is a constant depth.

150 more elements

Dependencies are inferred from the claim text.

Generating scanning spot locations for laser eye surgery

Life of this patent

Generating scanning spot locations for laser eye surgery

Life of this patent

Abstract

Claims26