U.S. patent application number 14/198409 was filed with the patent office on 2014-09-18 for short pulse laser with adjustable pulse length.
The applicant listed for this patent is AMO Development LLC.. Invention is credited to Gennady Imeshev.
Application Number | 20140276669 14/198409 |
Document ID | / |
Family ID | 51530857 |
Filed Date | 2014-09-18 |
United States Patent
Application |
20140276669 |
Kind Code |
A1 |
Imeshev; Gennady |
September 18, 2014 |
SHORT PULSE LASER WITH ADJUSTABLE PULSE LENGTH
Abstract
Embodiments of this invention relate to a system and method for
performing laser ophthalmic surgery. The surgical laser system
configured to deliver a laser pulse to a patient's eye comprises a
laser engine that includes a compressor configured to compress
laser light energy received, the compressor comprising a dispersion
or spectrum altering component provided on a computer controlled
stage connected to a computing device. A user providing an
indication of a desired pulse width received by the computing
device causes the computing device to reposition the stage and the
component provided thereon, resulting in a different pulse length
being transmitted by the laser engine.
Inventors: |
Imeshev; Gennady; (Irvine,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AMO Development LLC. |
Santa Ana |
CA |
US |
|
|
Family ID: |
51530857 |
Appl. No.: |
14/198409 |
Filed: |
March 5, 2014 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61794651 |
Mar 15, 2013 |
|
|
|
Current U.S.
Class: |
606/3 ;
606/6 |
Current CPC
Class: |
A61F 9/0084 20130101;
A61F 2009/00887 20130101; A61F 2009/0087 20130101; A61F 2009/00889
20130101; A61F 2009/00872 20130101; A61F 9/00825 20130101; A61B
18/20 20130101 |
Class at
Publication: |
606/3 ;
606/6 |
International
Class: |
A61F 9/008 20060101
A61F009/008 |
Claims
1. A surgical laser system configured to deliver a laser pulse to a
patient's eye, comprising: a laser engine, having a compressor
configured to compress laser light energy received, the compressor
comprising a dispersion altering component provided on a computer
controlled stage connected to a computing device; wherein a user
providing an indication of a desired pulse width received by the
computing device causes the computing device to reposition the
stage and the component provided thereon, resulting in a different
pulse length being transmitted by the laser engine.
2. A surgical laser system configured to deliver a laser pulse to a
patient's eye, comprising: a laser engine, having a compressor
configured to compress laser light energy received, the compressor
comprising a spectrum altering component provided on a computer
controlled stage connected to a computing device; wherein a user
providing an indication of a desired pulse width received by the
computing device causes the computing device to reposition the
stage and the component provided thereon, resulting in a different
pulse length being transmitted by the laser engine.
3. The surgical laser system of claim 1 wherein the laser pulse has
a wavelength in the range of 300 nm to 3000 nm.
4. The surgical laser system of claim 1 wherein the compressor
further comprises a separate dispersion adjustment element
configured to change the pulse width of the laser light energy.
5. The surgical laser system of claim 1 wherein the compressor
further comprises a separate dispersion adjustment element, the
separate dispersion adjustment element configured to provide a
fixed level of dispersion when positioned in a beam path of the
laser pulse and no dispersion when removed from the beam path.
6. The surgical laser system of claim 2 wherein the laser pulse has
a wavelength in the range of 300 nm to 3000 nm.
7. The surgical laser system of claim 2 wherein the compressor
further comprises a separate dispersion adjustment element
configured to change the pulse width of the laser light energy.
8. The surgical laser system of claim 2 wherein the compressor
further comprises a separate dispersion adjustment element, the
separate dispersion adjustment element configured to provide a
fixed level of dispersion when positioned in a beam path of the
laser pulse and no dispersion when removed from the beam path.
Description
RELATED APPLICATION
[0001] This application claims the benefit of priority to U.S.
Provisional Patent Application No. 61/794,651, filed on Mar. 15,
2013, the entire disclosure of which is incorporated herein by
reference.
BACKGROUND
[0002] 1. Field
[0003] Embodiments of this present invention generally relate to
laser systems, and more specifically, to the application of laser
pulses during surgical procedures such as laser-assisted ophthalmic
surgery.
[0004] 2. Background
[0005] Eye surgery is now commonplace with some patients pursuing
it as an elective procedure to avoid using contact lenses or
glasses and others pursuing it to correct adverse conditions such
as cataracts. Moreover, with recent developments in laser
technology, laser surgery has become the technique of choice for
ophthalmic procedures. Laser eye surgery typically uses different
types of laser beams, such as ultraviolet lasers, infrared lasers,
and near-infrared, ultra-short pulsed lasers, for various
procedures and indications.
[0006] A surgical laser beam is preferred over manual tools like
microkeratomes as it can be focused accurately on extremely small
amounts of ocular tissue, thereby enhancing precision and
reliability. For example, in the commonly-known LASIK (Laser
Assisted In Situ Keratomileusis) procedure, an ultra-short pulsed
laser is used to cut a corneal flap to expose the corneal stroma
for photoablation with an excimer laser. Ultra-short pulsed lasers
emit radiation with pulse durations as short as 10 femtoseconds and
as long as 3 nanoseconds, and a wavelength between 300 nm and 3000
nm. Besides cutting corneal flaps, ultra-short pulsed lasers are
used to perform cataract-related surgical procedures, including
capsulorhexis, capsulotomy, as well as softening and/or breaking of
the cataractous lens.
[0007] In laser surgery performed with an ultra-short pulsed laser,
the laser engine is configured to deliver a laser beam with
ultra-short pulse durations (which may be as long as a few
nanoseconds or as short as a few femtoseconds) to a patient's eye.
Temporal pulse profile and the pulse width are generally static in
that they do not change during a procedure or during different
phases of a procedure. Nor do they change when different procedures
are performed separately, such as, for example, a capsulorhexis, a
capsulotomy, lens fragmentation, corneal incisions, and the
like.
[0008] Nevertheless, some issues may arise during different
surgical procedures. As a specific example, certain types of
ophthalmic incisions may require one type of laser profile, while
another type of incision may benefit from a profile having a
different pulse length. Conventional laser systems have a limited
or non-existent ability to change the laser pulse profile. Where
the ability is limited, the laser pulse may be changed to a desired
profile, but only after one phase of a surgical procedure is
completed with the initial profile. To change the laser's pulse
profile, an operator must manually adjust the positions of certain
system components, or make time consuming changes to the components
themselves. Once this process is completed, the device may be
powered on to commence another phase of the procedure. As may be
appreciated, time delay is highly undesirable.
[0009] As such, there is a need for an ultra-short pulsed surgical
laser system that overcomes the limited pulse profile capabilities
available in conventional systems. In particular, it would be
beneficial to offer a more robust ability to alter laser pulse
profiles during laser-assisted refractive and cataract
surgeries.
SUMMARY
[0010] Embodiments of this invention include a surgical laser
system and method for performing ophthalmic surgery. The laser
system includes a laser engine configured to deliver a pulsed beam
to a patient's eye, wherein the engine includes a compressor
configured to compress laser light energy received, the compressor
comprising a dispersion or spectrum altering component provided on
a computer controlled stage connected to a computing device. A user
provides an input to a computing device regarding a desired pulse
width causes the computing device to reposition the stage and the
component provided thereon, which results in a different pulse
length to be transmitted by the laser engine.
[0011] This summary and the following detailed description are
merely exemplary, illustrative, and explanatory, and are not
intended to limit, but to provide further explanation of the
invention as claimed. Additional features and advantages of the
invention will be set forth in the descriptions that follow, and in
part will be apparent from the description, or may be learned by
practice of the invention. The objectives and other advantages of
the invention will be realized and attained by the structure
particularly pointed out in the written description, claims and the
appended drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 illustrates a general overview of a non-UV,
ultra-short pulse laser arrangement configured to employ the
present design.
[0013] FIG. 2 is a general diagram of the components of a non-UV,
ultra-short pulse bulk laser engine in an ophthalmic surgical laser
system.
[0014] FIG. 3 illustrates a bulk oscillator that may be employed
with the present design.
[0015] FIG. 4 is a pulse stretcher/compressor that may be employed
with the present design.
[0016] FIG. 5 shows an amplifier that may be employed with the
present design.
[0017] FIG. 6 is a conceptual illustration of a stage having a
component positioned thereon usable with the present design.
DETAILED DESCRIPTION
[0018] The drawings and related descriptions of the embodiments
have been simplified to illustrate elements that are relevant for a
clear understanding of these embodiments, while eliminating various
other elements found in conventional collagen shields, ophthalmic
patient interfaces, and in laser eye surgical systems. Those of
ordinary skill in the art may thus recognize that other elements
and/or steps are desirable and/or required in implementing the
embodiments that are claimed and described. But, because those
other elements and steps are well known in the art, and because
they do not necessarily facilitate a better understanding of the
embodiments, they are not discussed. This disclosure is directed to
all applicable variations, modifications, changes, and
implementations known to those skilled in the art. As such, the
following detailed descriptions are merely illustrative and
exemplary in nature and are not intended to limit the embodiments
of the subject matter or the uses of such embodiments. As used in
this application, the terms "exemplary" and "illustrative" mean
"serving as an example, instance, or illustration." Any
implementation described as exemplary or illustrative is not meant
to be construed as preferred or advantageous over other
implementations. Further, there is no intention to be bound by any
expressed or implied theory presented in the preceding background
of the invention, brief summary, or the following detailed
description.
[0019] FIG. 1 illustrates a general overview of a laser arrangement
configured to employ the present design. From FIG. 1, laser engine
100 includes laser source 101 and provides laser light to variable
attenuator 102 configured to attenuate the beam, then to energy
monitors 103 to monitor beam energy level, and first safety shutter
104 serving as a shutoff device if the beam is unacceptable. Beam
steering mirror 105 redirects the resultant laser beam to the beam
delivery device 110, through articulated arm 106 to range finding
camera 111. The range finding camera 111 determines the range
needed for the desired focus at the eye 120. Beam delivery device
110 includes second safety shutter 112 and beam monitor 113, beam
pre-expander 114, X-Y (position) scanner 115, and zoom beam
expander 116. Zoom beam expander 116 expands the beam toward IR
mirror 117 which reflects and transmits the received beam. Mirror
118 reflects the received beam to video camera 119, which records
the surgical procedure on the eye 120. IR mirror 117 also reflects
the laser light energy to objective lens 121, which focuses laser
light energy to eye 120.
[0020] In ophthalmic surgery using a pulsed laser beam,
non-ultraviolet (UV), ultra-short pulsed laser technology can
produce pulsed laser beams having pulse durations measured in the
femtoseconds and picoseconds range. An exemplary ultra-short pulsed
laser system shown in FIG. 1 can provide an intrastromal
photodisruption technique for reshaping the cornea using a non-UV,
ultra-short (e.g., femtosecond pulse duration), pulsed laser beam
produced by laser source 101 that propagates through corneal tissue
and is focused at a point below the surface of the cornea to
photodisrupt stromal tissue at the focal point.
[0021] Although the system may be used to photoalter a variety of
materials (e.g., organic, inorganic, or a combination thereof), the
system is suitable for ophthalmic applications in one embodiment.
The focusing optics, such as beam pre-expander 114, zoom beam
expander 116, IR mirror 117 and objective lens 121, direct the
pulsed laser beam toward an eye 120 (e.g., onto or into a cornea)
for plasma mediated (e.g., non-UV) photoablation of superficial
tissue, or into the stroma of the cornea for intrastromal
photodisruption of tissue. In this embodiment, the system may also
include a lens to change the shape (e.g., flatten or curve) of the
cornea prior to scanning the pulsed laser beam toward the eye. The
system is capable of generating the pulsed laser beam with physical
characteristics similar to those of the laser beams generated by a
laser system disclosed in U.S. Pat. Nos. 4,764,930 and 5,993,438,
which are incorporated herein.
[0022] The ophthalmic laser system can produce an ultra-short
pulsed laser beam for use as an incising laser beam. This pulsed
laser beam preferably has laser pulses with durations as long as a
few nanoseconds or as short as a few femtoseconds. For intrastromal
photodisruption of the tissue, the pulsed laser beam has a
wavelength that permits the pulsed laser beam to pass through the
cornea without absorption by the corneal tissue. The wavelength of
the pulsed laser beam is generally in the range of about 300 nm to
about 3000 nm, and the irradiance of the pulsed laser beam for
accomplishing photodisruption of stromal tissues at the focal point
is typically greater than the threshold for optical breakdown of
the tissue. Although a non-UV, ultra-short pulsed laser beam is
described in this embodiment, the pulsed laser beam may have other
pulse durations and different wavelengths in other embodiments.
Further examples of devices employed in performing ophthalmic laser
surgery are disclosed in, for example, U.S. Pat. Nos. 5,549,632,
5,984,916, and 6,325,792, which are incorporated here by
reference.
[0023] FIG. 2 illustrates general diagram of the components of a
non-UV, ultra-short pulse laser engine in an ocular laser surgical
system including laser engine 101. From FIG. 2, there is provided
an oscillator 201, a beam stretcher/pulse compressor 202, and an
amplifier 203. Controller 204 may be provided in the embodiments
discussed herein. Lasers producing pulses in the
femtosecond/picosecond duration range operate and generate pulses
at high peak power levels, and if left unaltered can damage the
gain medium. To address this issue, chirped pulse amplification
(CPA) is employed wherein the length of pulses are extended or
stretched to the picosecond range, resulting in a significant
reduction in pulse peak power. From FIG. 2, the oscillator 201
generates and outputs a beam of femtosecond laser pulses. The pulse
stretcher/compressor 202 extends the duration of the received
pulses. Amplifier 203 increases amplitude of the pulses. The pulse
stretcher/compressor then recompressed pulses to the femtosecond
range prior to delivery.
[0024] FIG. 3 illustrates an oscillator 301 used in a femtosecond
bulk laser surgical device. Oscillator 301 includes laser pump 302
which directs laser light energy to focusing lens 303A and a
dichroic mirror 303B, which both transmits the pump beam but
reflects the cavity beam. In one path the cavity beam passes to
mirror 309, aperture 310, mirror 307, and SESAM "HR" mirror 308. As
used herein, the term "mirror" or "mirrors" is intended broadly to
mean any type of reflective surface or surfaces. The other path
from the dichroic mirror 303B is directed to oscillator glass
assembly 304, horizontally polarized at Brewster's angle, to mirror
305, mirror 306, output coupler 311, and light energy ultimately
passes out of oscillator 301 to mirror 312, beamsplitter 313, and
pulse stretcher/compressor 202, not shown in this view.
[0025] FIG. 4 illustrates the components of pulse
stretcher/compressor 401, which receives the beam under half mirror
402, with light passing to half wave plate 403, and one of a number
of mirrors 404, over half mirror 405, to grating 406, stretcher
lens 407, folding mirror 408, an stretcher mirror 409. The beam
then travels through elements 408, 407 and 406 to half mirror 405
that reflects the beam back to another double-pass through the
grating 406 and other elements. The beam then goes over half mirror
405 to elements 404 and 403. The beam is then gets reflected by
half mirror 402 to reflective surface 410, which provides light
energy to Faraday (three port) isolator 411, configured to receive
and provide light energy to and from mirrors 412 and 420. As shown,
mirror 412 provides light energy to half wave plate 413 and to an
amplifier (not shown in this view). Light from half mirror 420
passes to mirror 419, grating 406, and to compressor
retro-reflection assembly 415, including mirrors 416 and 417, back
through grating 406 and to mirror 418. Light beam then passes
through the grating 406, retro-reflection assembly 415, grating
406, to mirror 419. The light beam travels over half mirror 420 to
mirror 421, to folding mirror 422, and to energy wheel 423, to beam
splitters 424 and 425, fast shutter 426, and folding mirror to
articulating arm 427. Light from beam splitters 424 and 425 are
directed to the other components of the surgical system.
[0026] FIG. 5 illustrates one embodiment of an amplifier 501 in
accordance with the design of FIG. 2A, again including a number of
mirrors as well as amp out photodiode 503, polarizer assembly 504,
mirror 505, Pockels cell 506, mirror 507, and Q-switch photo diode
508. Also shown is a folding mirror 510, mirror 511, mirror 512 on
a translation device, amplifier glass assembly 513, focusing lenses
514, and pump diode 515.
[0027] One embodiment of the present design employs the arrangement
of FIGS. 3-5. Lasers may be employed in the ocular surgical
environment to perform a variety of different cuts, such as corneal
cuts, capsulotomy cuts, and lens fragmentation cuts. Each of these
cuts is optimally performed using a different length pulse. For
example, a corneal cut may use pulses in the 400-800 femtoseconds
range, while lens fragmentation cuts may use pulses in the 1-5
picoseconds range. It would be advantageous to offer a surgeon an
ability to achieve different pulse lengths when the surgeon
switches from one desired pulse length to another desired pulse
length with little effort required, unlike previous devices wherein
extensive and/or manual component repositioning was required to
alter pulse length.
[0028] The present design employs computer controlled adjustment of
pulse length by changing the dispersion of the pulse compressor,
pulse stretcher, or other components or assemblies in the beam
path. Detuning the compressor from its optimal operating point
tends to lengthen output pulses. One change of the design is to
change the effective grating separation. This can be achieved by
moving the stage 415 with mounted roof mirror 416-417 along the
beam path indicated. In one embodiment, grating 406 may be
repositioned, rotated, or otherwise altered to provide pulses of
different lengths. Multiple components illustrated in FIG. 4 may be
placed on stages and moved in a relatively short amount of time. As
an example, the device may offer two different pulse lengths, and
may offer two different positions for the various components.
Components including but not limited to each of the reflective
surfaces as well as one or more of grating 406, stretcher lens 407,
folding mirror 408, and stretcher mirror 409, Faraday (three port)
isolator 411, half wave plate 413, compressor retro-reflection
assembly 415, folding mirror 422, energy wheel 423, fast shutter
426, and/or folding mirror to articulating arm 427 may be
positioned on a stage or stages and may be translated and/or
rotated to a desired second position to effectuate the second pulse
length setting. Alternately, an alternate component may be switched
in or out for an existing component to effectuate the second mode
of operation. More positions and more pulse length options may be
achieved by offering variable positioning of components.
Alternatively, a pulse spectral shape or width may be altered (for
example, by filtering spectral components within the stretcher or
compressor) to adjust temporal pulse length.
[0029] Translation and/or rotation or substitution of components
may be achieved using computer controlled motorized stages. During
manufacturing or service, pulse length can be determined for more
than one position or orientation of a given stage and the setting
of both the stage and the resultant pulse length stored in computer
memory. During surgery, the user may select a particular pulse
length to achieve a particular cut, and the computer 204 may
command the stage to translate or rotate or otherwise be
repositioned to an available position to achieve desired pulse
length.
[0030] A further alternative in FIG. 4 is to lengthen the distance
between grating 406 and compressor retro-reflection assembly 415,
which would lengthen the resultant pulses. Again, a computer
controlled stage may be employed to effectuate the desired position
of the components. A further alternative would be to substitute a
second grating for grating 406, such that a computer controlled
stage may substitute in and/or reposition a second grating (not
shown) in place of and/or in a position differing from grating 406.
Other components may be reoriented to effectuate a desired change
in position.
[0031] While illustrated with respect to a bulk-grating compressor,
the present design may be employed in other types of compressors,
including prism based compressors wherein components such as
mirror(s), prism(s), and so forth may be provided on stages and
adjusted, moved, rotated, translated, or substituted to alter pulse
length. Alternately, a grism, generally a combination between a
grating and a prism, may be employed in the compressor, and grism
components and components associated with the grism may be provided
on stages and adjusted, moved, rotated, translated, or substituted
using computer control to alter pulse length.
[0032] A further implementation may include a separate dispersion
adjustment element added to a compressor, stretcher, or elsewhere
in the beam path such as assembly 401 in FIG. 4, that adjusts
dispersion either continuously or in steps. Use of a dispersion
element can change the pulse width when employed with a compressor.
Alternately, the dispersion adjustment element can provide a fixed
level of dispersion when positioned in the beam path or no
dispersion when removed from the beam path.
[0033] FIG. 6 is a general representative drawing of a motorized
stage that may be used with the design illustrated in FIG. 4 and
includes components illustrated in FIG. 4. Mirrors 416 and 417 are
root reflectors positioned on a motorized stage 415 configured to
move toward and away from grating 406. Such movement tends to
stretch or compress the pulses received. In the beam path
illustrated, light passes to grating 406, mirror 416, mirror 417,
back to grating 406, and to mirror 418, where it is reflected as a
retro beam. Computer 601 controls the motorized stage to move in
the direction shown.
[0034] Thus, the present design comprises offering a set of
components in a laser engine compressor configured to be
mechanically repositioned or replaced in order to alter pulse
length of the resultant laser output. In one embodiment, at least
one component is placed on a mechanical stage connected to a
controller such that when a different pulse length is selected, the
computer provides a command to move the stage and the component
located thereon. Such movement alters the pulse width of the
resultant pulse delivered to the patient in a surgical procedure
such as a femtosecond laser ocular surgical procedure.
[0035] In another embodiment, multiple components may be
repositioned, and in another embodiment, certain components may be
replaced with other components or removed form or inserted into the
beam path using computer control. Mechanical stages may be employed
with any components in a pulse stretcher/pulse compressor or
elsewhere in the beam path including but not limited to gratings,
prisms, grisms, reflective surfaces or mirrors, half wave plates,
lens assemblies or focusing lenses, retro-reflect assemblies,
Faraday isolators, folding mirrors, half mirrors, energy wheels,
and/or dispersion elements.
[0036] Those of skill in the art will recognize that the step of a
method described in connection with an embodiment may be
interchanged without departing from the scope of the invention.
Those of skill in the art would also understand that information
and signals may be represented using any of a variety of different
technologies and techniques. Skilled artisans may implement the
described functionality in varying ways for each particular
application, but such implementation decisions should not be
interpreted as causing a departure from the scope of the present
invention. An apparatus implementing the techniques or components
described herein may be a stand-alone device or may be part of a
larger device.
[0037] Although embodiments of this invention are described and
pictured in an exemplary form with a certain degree of
particularity, describing the best mode contemplated of carrying
out the invention, and of the manner and process of making and
using it, those skilled in the art will understand that various
modifications, alternative constructions, changes, and variations
can be made in the ophthalmic interface and method without
departing from the spirit or scope of the invention. Thus, it is
intended that this invention cover all modifications, alternative
constructions, changes, variations, as well as the combinations and
arrangements of parts, structures, and steps that come within the
spirit and scope of the invention as generally expressed by the
following claims and their equivalents.
* * * * *