Optical System for Ophthalmic Surgical Laser
A laser system for ophthalmic surgery includes a laser source to produce a pulsed laser beam, an XY scanner to scan the pulsed laser beam in XY directions transverse to a Z axis, a Z scanner, to scan the XY scanned laser beam along the Z axis, and an objective, to focus the XYZ scanned laser beam into a target region.
1 . A laser system for ophthalmic surgery, comprising:
a laser source to produce a pulsed laser beam;
an XY scanner to scan the pulsed laser beam in XY directions transverse to a Z axis;
a Z scanner, to scan the XY scanned laser beam along the Z axis; and
an objective, to focus the XYZ scanned laser beam into a target region; wherein
the focused scanned laser beam has a numerical aperture NA and a Strehl ratio S at radial coordinates (z, r), in millimeters, at any azimuth angle φ, in the target region;
in a vicinity of (z, r)=(0.3, 0.0), NA is between 0.25 and 0.40 and S is between 0.8 and 1.0; and
NA and S fall within at least one of the following respective target ranges
in a vicinity of (z, r)=(0.3, 6.2), NA is between 0.25 and 0.40 and S is between 0.8 and 1.0;
in a vicinity of (z, r)=(8.0, 0.0), NA is between 0.15 and 0.35 and S is between 0.8 and 1.0; and
in a vicinity of (z, r)=(7.4, 4.0), NA is between 0.15 and 0.35 and S is between 0.8 and 1.0.
2 . The laser system of claim 1 , wherein:
NA and S fall within two of the three respective target ranges.
3 . The laser system of claim 1 , wherein:
NA and S fall within all three respective target ranges.
4 . The laser system of claim 1 , wherein:
the vicinity of the radial coordinates (z, r) comprises points, whose radial coordinates do not deviate more than P(radial) percentage from the radial coordinates (z, r); wherein
P(radial) is one of 10%, 20%, and 30%.
5 . The laser system of claim 1 , wherein:
in a vicinity of (z, r)=(0.3, 0.0), NA is between 0.30 and 0.35 and S is between 0.8 and 1.0; and
NA and S fall within at least one of the following respective target ranges
in a vicinity of (z, r)=(0.3, 6.2), NA is between 0.30 and 0.35 and S is between 0.8 and 1.0;
in a vicinity of (z, r)=(8.0, 0.0), NA is between 0.20 and 0.25 and S is between 0.8 and 1.0; and
in a vicinity of (z, r)=(7.4, 4.0), NA is between 0.20 and 0.25 and S is between 0.8 and 1.0.
6 . The laser system of claim 5 , wherein:
NA and S fall within two of the three respective target ranges.
7 . The laser system of claim 5 , wherein:
NA and S fall within all three respective target ranges.
8 . The laser system of claim 5 , wherein:
the vicinity of the radial coordinates (z, r) comprises points, whose radial coordinates do not deviate more than a P(radial) percentage from the radial coordinates (z, r);
wherein
P(radial) is one of 10%, 20%, and 30%.
9 . The laser system of claim 1 , wherein:
the NA and S values refer to the laser system being optically coupled, via a patient interface, to one of a human eye; and
a model of an eye.
10 . The laser system of claim 9 , wherein the model of the eye comprises:
a first surface, a second surface and a third surface;
defining
a corneal region, with thickness of about 0.6 mm and index of refraction of about 1.38;
an antechamber region, with a thickness in the range of 2 mm to 4 mm and an index of refraction of about 1.34; and
a lens region, with a thickness in the range of 3 mm to 5 mm and index of refraction of about 1.42; and
the three surfaces all having curvatures in the range of −100 m −1 to −80 m −1 .
11 . The laser system of claim 1 , further comprising:
a precompensator, disposed between the laser source and the XY scanner.
12 . The laser system of claim 11 , wherein:
the precompensator has a movable lens to Z scan the laser beam.
13 . The laser system of claim 1 , the Z scanner configured:
to adjust a Z focal depth and a numerical aperture NA essentially independently.
14 . The laser system of claim 1 , the Z scanner comprising:
a first lens group; and
a movable beam scanner.
15 . The laser system of claim 1 , wherein
the Z scanner is located before and separately from the objective.
16 . A laser system for ophthalmic surgery, comprising:
a laser source to produce a pulsed laser beam;
an XY scanner to scan the pulsed laser beam in XY directions transverse to a Z axis;
a Z scanner, to scan the XY scanned laser beam along the Z axis; and
an objective, to focus the XYZ scanned laser beam into a target region; wherein
the focused scanned laser beam has a focal spot with a focal spot radius;
the focal spot radius is less than r f (max) in the target region; and
the target region extends about 8 millimeter along the Z axis and about 10 millimeter in the XY directions.
17 . The laser system of claim 16 , wherein
r f (max) is 2 micrometers.
18 . The laser system of claim 16 , wherein
r f (max) is 4 micrometers.
19 . The laser system of claim 16 , wherein:
r i (max) refers to the laser system coupled to one of
a human eye; and
a model of the human eye.