U.S. patent application number 16/593138 was filed with the patent office on 2020-04-09 for occlusion sensing in ophthalmic laser probes.
The applicant listed for this patent is Alcon Inc.. Invention is credited to Gerald David Bacher, Nikki Koe, Bruno Lassalas, Alireza Mirsepassi, Dean Richardson, Ronald T. Smith.
Application Number | 20200107960 16/593138 |
Document ID | / |
Family ID | 68242795 |
Filed Date | 2020-04-09 |
United States Patent
Application |
20200107960 |
Kind Code |
A1 |
Bacher; Gerald David ; et
al. |
April 9, 2020 |
OCCLUSION SENSING IN OPHTHALMIC LASER PROBES
Abstract
In certain embodiments, a system for sensing occlusions in an
optical system includes a first laser source configured to generate
optical signals and a set of optical elements arranged to receive
the optical signals from the first laser source and to direct the
optical signals along a beam path. The system also includes a
detector arranged to receive reflections of the optical signals
travelling along at least a portion of the beam path and a control
system communicably coupled to the detector. The control system is
configured to detect, based on signals generated by the detector,
reflection signals associated with the reflections of the optical
signals, and disable a second laser source based on detection of
the reflection signals.
Inventors: |
Bacher; Gerald David;
(Carlsbad, CA) ; Koe; Nikki; (Irvine, CA) ;
Lassalas; Bruno; (Foothill Ranch, CA) ; Mirsepassi;
Alireza; (Irvine, CA) ; Richardson; Dean;
(Aliso Viejo, CA) ; Smith; Ronald T.; (Irvine,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Alcon Inc. |
Fribourg |
|
CH |
|
|
Family ID: |
68242795 |
Appl. No.: |
16/593138 |
Filed: |
October 4, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62742075 |
Oct 5, 2018 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 2018/2266 20130101;
A61B 2017/00123 20130101; G02B 27/10 20130101; A61B 18/22 20130101;
A61F 9/00821 20130101; A61B 2018/00636 20130101; A61B 2018/00785
20130101; A61B 2018/00898 20130101; A61F 2009/00863 20130101 |
International
Class: |
A61F 9/008 20060101
A61F009/008; G02B 27/10 20060101 G02B027/10; A61B 18/22 20060101
A61B018/22 |
Claims
1. A system for sensing occlusions in an optical system,
comprising: a first laser source configured to generate optical
signals; a set of optical elements arranged to receive the optical
signals from the first laser source and to direct the optical
signals along a beam path; a detector arranged to receive
reflections of the optical signals travelling along at least a
portion of the beam path; and a control system comprising a
processor and memory storing executable instructions, the control
system communicably coupled to the detector, wherein the
instructions, when executed by the processor, enable the control
system to: detect, based on signals generated by the detector,
reflection signals associated with the reflections of the optical
signals; and disable a second laser source based on detection of
the reflection signals.
2. The system of claim 1, further comprising a function generator
communicably coupled to the first laser source, the function
generator configured to generate a modulation signal to modulate
the optical signals generated by the first laser source.
3. The system of claim 2, further comprising a lock-in amplifier
communicably coupled to the detector, the function generator, and
the control system, the lock-in amplifier configured to extract,
based on the modulation signal, the reflection signals from signals
generated by the detector.
4. The system of claim 1, wherein the set of optical elements
comprises a beamsplitter configured to transmit the optical signals
generated by the first laser source and reflect the reflections of
the optical signals toward the detector.
5. The system of claim 1, wherein the set of optical elements
comprises a dichroic mirror configured to reflect the optical
signals generated by the first laser source and to transmit optical
signals generated by the second laser source.
6. The system of claim 1, wherein the set of optical elements
comprises a terminating optical element, and the detector is
arranged to receive the reflections of the optical signals caused
by the terminating optical element.
7. The system of claim 1, wherein the set of optical elements is
arranged to direct the optical signals generated by the first laser
source toward an optical fiber, and at least one of the optical
elements in the set of optical elements is configured to direct
optical signals generated by the second laser source toward the
optical fiber.
8. The system of claim 1, wherein the control system is configured
to disable the second laser source based on a determination that a
magnitude of the reflection signals is above a threshold value.
9. The system of claim 1, wherein the first laser source is
configured to generate optical signals having a wavelength
different from that of the second laser source.
10. An ophthalmic surgical system, comprising: a connector
configured to couple to a surgical probe comprising one or more
optical elements; a treatment laser source; a probe laser source; a
detector; a set of optical elements configured to: receive a
treatment optical signal from the treatment laser source and direct
the treatment optical signal along a first beam path toward the one
or more optical elements of the surgical probe; receive a probe
optical signal from the probe laser source and direct the probe
optical signal along a second beam path toward the one or more
optical elements of the surgical probe; and receive a reflection of
the probe optical signal caused by one or more of the optical
elements in the surgical probe and direct the reflection of the
probe optical signal toward the detector; and a control system
comprising a processor and memory storing executable instructions,
the control system communicably coupled to the detector, wherein
the instructions, when executed by the processor, enable the
control system to: detect, based on signals generated by the
detector, a reflection signal associated with the reflection of the
probe optical signal; and disable the treatment laser source based
on detection of the reflection signal.
11. The system of claim 10, further comprising a function generator
communicably coupled to the probe laser source, the function
generator configured to generate a modulation signal to modulate
probe optical signals generated by the probe laser source.
12. The system of claim 11, further comprising a lock-in amplifier
communicably coupled to the detector, the function generator, and
the control system, the lock-in amplifier configured to extract,
based on the modulation signal, the reflection signals from the
signals generated by the detector.
13. The system of claim 10, wherein the set of optical elements
comprises a beamsplitter arranged to transmit the probe optical
signal along the second beam path and to reflect the reflection of
the probe optical signal toward the detector.
14. The system of claim 10, wherein the set of optical elements
comprises a dichroic mirror configured to transmit the treatment
optical signal and to reflect the probe optical signal.
15. The system of claim 10, wherein: the treatment laser source is
configured to generate the treatment optical signal having a
wavelength between 500-600 nm; and the probe laser source is
configured to generate the probe optical signal having a wavelength
between 600-700 nm or between 800-900 nm.
16. The system of claim 10, wherein the control system is
configured to disable the treatment laser source based on a
determination that a magnitude of the reflection signal is above a
threshold value.
17. A method for sensing occlusions in an optical system,
comprising: causing generation of probe optical signals by a first
laser source; obtaining signals generated by a detector based on
optical signals received at the detector; detecting, based on the
signals received from the detector, reflection signals associated
with reflections of the probe optical signals generated by the
first laser source; and disabling a second laser source in response
to detecting the reflection signals.
18. The method of claim 17, further comprising generating, by a
function generator, a modulation signal to modulate the probe
optical signals generated by the first laser source.
19. The method of claim 18, wherein detecting the reflection
signals comprises extracting, by a lock-in amplifier, the
reflection signals based on the modulation signal.
20. The method of claim 17, wherein disabling the second laser
source is based on a determination that a magnitude of the
reflection signals is above a threshold value.
Description
FIELD
[0001] The present disclosure relates to occlusion sensing in laser
probes, such as laser probes useful in ophthalmic surgical
procedures (e.g., multi-spot ophthalmic laser probes).
BACKGROUND
[0002] Laser probes may be useful in certain ophthalmic surgical
procedures, such as laser photocoagulation therapy. Laser
photocoagulation therapy addresses ocular conditions such as
retinal detachments and tears as well as proliferative retinopathy
resulting from diseases such as diabetes. The abnormally high blood
sugar in a diabetic stimulates the retinal vessels to release
growth factors that in turn encourage an undesirable proliferation
of blood vessels and capillaries over the retinal surface. These
proliferated blood vessels are very delicate and will readily bleed
into the vitreous. The body responds to the damaged vessels by
producing scar tissue, which may then cause the retina to detach
and eventually cause blindness.
[0003] In laser photocoagulation therapy, a laser probe, such as a
multi-spot laser probe, is used to burn spots across the retina. In
some cases, bleeding may occur during therapy, causing an occlusion
near the tip of the laser probe. In some cases, other types of
contaminants may be located near the probe tip, causing an
occlusion near the probe tip. Such occlusions may lead to
significant laser absorption at the tip, heating the probe tip and
causing thermal-induced failure of the probe or injury to the
patient.
SUMMARY
[0004] In certain embodiments, a system for sensing occlusions in
an optical system may include a first laser source configured to
generate optical signals and a set of optical elements arranged to
receive the optical signals from the first laser source and to
direct the optical signals along a beam path. The system may also
include a detector arranged to receive reflections of the optical
signals travelling along at least a portion of the beam path and a
control system communicably coupled to the detector. The control
system may be configured to detect, based on signals generated by
the detector, reflection signals associated with the reflections of
the optical signals, and disable a second laser source based on
detection of the reflection signals.
[0005] In certain embodiments, an ophthalmic surgical system may
include a connector configured to couple to a surgical probe that
includes one or more optical elements, a treatment laser source; a
probe laser source, a detector, and a set of optical elements. The
optical elements may be configured to receive a treatment optical
signal from the treatment laser source and direct the treatment
optical signal along a first beam path toward the optical elements
of the surgical probe, receive a probe optical signal from the
probe laser source and direct the probe optical signal along a
second beam path toward the optical elements of the surgical probe,
and receive reflections of the probe optical signals caused by one
or more of the optical elements in the surgical probe and direct
the reflections of the probe optical signals toward the detector.
The system may also include a control system communicably coupled
to the detector. The control system may be configured to detect,
based on signals generated by the detector, reflection signals
associated with the reflections of the probe optical signals and
disable the treatment laser source based on detection of the
reflection signals.
[0006] In certain embodiments, a method for sensing occlusions in
an optical system may include causing generation of first optical
signals by a first laser source, causing generation of second
optical signals by a second laser source, receiving, from a
detector, signals based on optical signals received at the
detector, detecting, based on the signals received from the
detector, reflection signals associated with the reflections of the
second optical signals, and disabling the first laser source in
response to detecting the reflection signals.
[0007] In some embodiments, a function generator may generate
modulation signals to modulate the optical signals used to detect
occlusions (e.g., by modulating the probe laser signals). In some
embodiments, a lock-in amplifier may be used to extract reflection
signals based on the modulation signal generated by the function
generator.
[0008] Certain embodiments may provide one or more advantages, in
some instances. For example, certain embodiments may allow for
sensing the presence or absence of blood or other contaminants on
laser probe tips. When blood or other contaminants that could lead
to probe failure or patient injury are sensed, a high-power
treatment laser may be disabled to avoid any such issues. Detection
of occlusions may be achieved prior to overheating of the laser
probe, whereas previous techniques for detecting occlusions, such
as blackbody-based techniques, may not detect occlusions until
overheating has occurred.
[0009] These and other advantages will be apparent to those skilled
in the art in view of the present drawings and specification.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] For a more complete understanding of the present disclosure
and the advantages thereof, reference is now made to the following
description taken in conjunction with the accompanying drawings in
which like reference numerals indicate like features and
wherein:
[0011] FIG. 1 is a diagram of an example ophthalmic surgical system
that includes a laser probe.
[0012] FIG. 2 is a diagram of an example of a multi-spot laser
probe for use with an ophthalmic surgical system.
[0013] FIG. 3 illustrates aspects of an example multi-spot laser
probe in operation.
[0014] FIG. 4 is a diagram showing an example system for sensing
occlusions in a laser probe of an ophthalmic surgical system.
[0015] FIG. 5 is a flow diagram of an example process for sensing
occlusions in an optical system, such as in a laser probe of an
ophthalmic surgical system.
[0016] One skilled in the art will understand that the drawings,
described below, are for illustration purposes only, and are not
intended to limit the scope of applicant's disclosure.
DETAILED DESCRIPTION
[0017] For the purposes of promoting an understanding of the
principles of the present disclosure, reference will now be made to
the embodiments illustrated in the drawings, and specific language
will be used to describe the same. It will nevertheless be
understood that no limitation of the scope of the disclosure is
intended. Alterations and further modifications to the described
systems, devices, and methods, and any further application of the
principles of the present disclosure are contemplated as would
normally occur to one skilled in the art to which the disclosure
relates. In particular, it is contemplated that the systems,
devices, and/or methods described with respect to one embodiment
may be combined with the features, components, and/or steps
described with respect to other embodiments of the present
disclosure. For the sake of brevity, however, the numerous
iterations of these combinations will not be described separately.
For simplicity, in some instances the same reference numbers are
used throughout the drawings to refer to the same or like
parts.
[0018] FIG. 1 is a diagram of an example ophthalmic surgical system
100 that includes a laser probe 106. The example system 100
includes a console 102 with a control system 104 and a laser system
110. In the example shown, the laser system 110 is in optical
communication with the laser probe 106 through optical fibers 111,
112. The optical fiber 112 may attach to the console via connector
113. The connector 113 may include one or more optical elements for
optically aligning the optical fibers 111, 112. The laser system
110 and laser probe 106 may be in optical communication via other
techniques or implementations.
[0019] In some implementations, the example laser probe 106 is used
by an operator (e.g., a surgeon) during a surgical procedure
relating to the eye. For example, the laser probe 106 may be used
in a laser photocoagulation therapy procedure for the eye of the
patient 108, wherein the laser probe 106 is used to burn spots in
the retina of the eye using a high-power treatment laser. A distal
end of the laser probe 106 may be inserted into the eye of a
patient 108 during such a procedure, as shown in FIG. 1.
[0020] In some cases, blood or other substances may cause an
occlusion near the tip of the laser probe, leading to significant
energy absorption at the tip of the laser probe 106 (i.e., the
distal end of the laser probe 106), heating the probe tip and
potentially causing thermal-induced failure of the probe or injury
to the patient 108. Thus, in some embodiments, the laser system 110
may include a system for sensing such occlusions using a relatively
low-power probe laser. In some cases, for example, the laser system
110 may include one or more of the components shown in FIG. 4 and
described further below.
[0021] The example control system 104 that provides signals to one
or more components of the laser system 110 to control operation of
the laser system 110 or to perform other functions or operations as
described herein. The control system 104 may include a processor, a
memory, software, and firmware that are configured to perform such
functions and operations. For example, in some embodiments, the
control system 104 is implemented similar to the control system 424
of FIG. 4, as described further below.
[0022] The example laser system 110 generates optical signals for
performing aspects of a surgical procedure on the eye of the
patient 108. For example, the laser system 110 may include a
femtosecond laser oscillator, such as a Ytterbium-based (e.g., a
Yb:Glass or Yb-doped fiber) laser, an Erbium-based (e.g., an
Er-doped fiber) laser, a Titanium Sapphire (TiAl2O3) laser,
Chromium-based (e.g., Cr:LiSAF Cr:LiCAF, or Cr:LiSGAF) laser, an
Alexandrite laser, a neodymium-doped yttrium aluminum garnet
(Nd:YAG) laser, a semiconductor- or dye-based laser, or another
type of laser for use in the surgical procedure. In some
embodiments, the laser system 110 may include one or more of the
components shown in FIG. 4 and described below.
[0023] FIG. 2 is a diagram of an example of a multi-spot laser
probe 200 for use with an ophthalmic surgical system (e.g., the
ophthalmic surgical system 100 of FIG. 1). In the example shown,
the multi-spot laser probe 200 generates four laser spots 208
simultaneously. Probe 200 comprises a handle 202 sized and shaped
for grasping by a user, such as an ophthalmic surgeon. Probe 200
further includes a cannula extending from handle 202 and 204 having
a tip 206 at a distal end (which may or may not be curved as shown
in various embodiments). Cannula 204 is adapted for insertion into
a patient's eye and may be cylindrically shaped. In various
examples, cannula 204 may be made of stainless steel, titanium,
nickel, nickel titanium (Nitinol), or platinum-iridium, and may be
23 Gauge, 25 Gauge, or 27 Gauge.
[0024] In operation, one or more laser beams from a laser source
(e.g., a laser within the laser system 110 of FIG. 1) are
transmitted through one or more optical fibers within handle 202
and cannula 204 and delivered from the distal tip 206 onto a
retina, producing spots 208. In some examples, probe 200 comprises
multiple fibers or a multi-core fiber, each transmitting a laser
beam which produces a separate one of spots 208. In other examples,
a single fiber may transmit a laser beam which is split (e.g.,
using a spherical lens or gradient-index (GRIN) lens in probe 200)
to produce each one of spots 208. Various multi-spot laser probe
designs are described in U.S. Pat. No. 8,951,244, which is
incorporated by reference herein in its entirety.
[0025] FIG. 3 illustrates aspects of an example multi-spot laser
probe in operation. In this example, distal end 300 of a multi-spot
laser probe includes a 2.times.2 fiber array (which may comprise
multiple fibers or a multi-core fiber) optically coupled to lens
304 located at the probe tip 306 within a cannula 301. In this
design, lens 304 is the distalmost optical element of probe 300,
and the distal surface of lens 304 is in physical contact with eye
tissue 310 while probe 300 is inserted in an eye during a
procedure. Other embodiments may include additional elements or
features. In operation, laser light is transmitted through fiber
array 302, refracted by lens 304, and projected onto a retina as a
plurality of laser spots.
[0026] In some surgical cases, blood or another contaminant may
build up at or near probe tip 306, causing an occlusion. For
example, blood can occlude at the distal surface 305 of lens 304
during a surgical procedure. Blood occluded at distal surface 305
may char and absorb energy from a laser, causing the temperature of
lens 304 to rise, potentially causing the lens 304 to melt,
adhesives to fail, or injury to the patient. In other instances,
blood or another foreign element or contaminant may seep into the
space between the outer surface of lens 304 and the inner surface
of cannula 301. As in the prior example, such substances may absorb
the laser energy, causing the temperature of lens 304 to rise and
potentially lead to the issues previously described.
[0027] In some cases, an optical element may be located distal to
the lens 304. The optical element may be designed to isolate and
protect lens 304 (and other components in the probe) from exposure
to foreign substances (e.g., tissue or blood in a surgical
environment), overheating, and melting. The optical element may
comprise one or more elements made of an optically clear material
with a high melting and high softening temperature, such as high
softening point ceramics or glasses, and may be the distalmost
optical element in the distal end 300. In certain examples, the
optical element may include sapphire or fused silica.
[0028] FIG. 4 is a diagram showing an example system 400 for
sensing occlusions in a laser probe of an ophthalmic surgical
system. In some embodiments, the example system 400 may be included
in a laser system of an ophthalmic surgical system such as the
laser system 110 of ophthalmic surgical system 100 of FIG. 1. The
example system 400 may be used, in some cases, to sense occlusions
in laser probes, such as multi-spot laser probes, used to perform
laser photocoagulation therapy. The example system 400 may also be
used to sense occlusions in other types of optical systems as well,
which might or might not relate to ophthalmic surgical procedures.
The system 400 may include additional, fewer, or different
components than those shown in FIG. 4. Further, the components of
system 400 may be arranged in another manner. For example, the
treatment laser source 402 and probe laser source 412 may be within
the same source and may be on the same axis as one another.
[0029] The example system 400 includes a treatment laser source 402
that generates optical signals for use in surgical procedures. For
example, the treatment laser source 402 may generate signals used
in laser photocoagulation therapy techniques. In some cases, the
treatment laser source 402 may include an intercavity-doubled
ND:TVO4 (Neodymium Vanadate) continuous wave laser (having a
wavelength of approximately 532 nm) or an Argon Ion laser (having a
wavelength of approximately 515 nm). In other cases, the treatment
laser source may include a femtosecond laser oscillator, such as a
Ytterbium-based (e.g., a Yb:Glass or Yb-doped fiber) laser, an
Erbium-based (e.g., an Er-doped fiber) laser, a Titanium Sapphire
(TiAl2O3) laser, Chromium-based (e.g., Cr:LiSAF Cr:LiCAF, or
Cr:LiSGAF) laser, an Alexandrite laser, a neodymium-doped yttrium
aluminum garnet (Nd:YAG) laser, a semiconductor- or dye-based
laser, or another type of laser for use in the surgical procedure.
The treatment laser source 402 may produce relatively high-power
optical signals. For example, the treatment laser source 402 may
produce optical signals with a power between approximately 30 mW to
3 W. In some embodiments, the treatment laser source 402 generates
optical signals having a wavelength between 500 nm and 700 nm
(e.g., approximately 532 nm, 577 nm, or 659 nm).
[0030] The example system 400 also includes a probe laser source
412 that generates optical signals used to detect the presence of
occlusions in the system 400. In some cases, the probe laser source
412 may include a semiconductor (diode) laser. The probe laser
source 412 may generate optical signals that are generally
low-power, especially when compared with the optical signals
generated by the treatment laser source 402. For example, the probe
laser source 412 may produce optical signals with a power between
approximately 100 uW to 5 mW. The wavelength of the signals
generated by the probe laser source 402 may be different from those
of the treatment laser source 402, and may be determined, in some
cases, by the type of contaminant to be detected by the system 400.
For instance, the wavelength of the optical signals generated by
the probe laser source 412 may be of a wavelength outside of the
absorption spectrum of the contaminant at issue. As an example, in
embodiments for detecting blood occlusions, the probe laser source
412 generates optical signals having a wavelength in the range of
approximately 600-700 nm (e.g., 635 nm or 650 nm) or in the range
of approximately 800-900 nm (e.g., 850 nm), since both wavelength
ranges are outside of the absorption spectrum of blood. In some
cases, the probe laser source 412 may be the same as the source of
the "aiming beam" in an ophthalmic surgical system. That is, the
aiming beam may serve a dual purpose of being used by a surgeon to
guide the surgical procedure (where the aiming beam shows where the
treatment beam is to be applied), and also to detect blood
occlusions (since such aiming beams may be between approximately
620-650 nm and therefore, outside of the absorption spectrum of
blood).
[0031] The example system 400 further includes a number of optical
elements for directing the optical signals generated by the
treatment laser source 402 and the probe laser source 412. For
instance, in the example shown, the system 400 includes a dichroic
mirror 404 and a lens 406, optical fiber 408, terminating optical
element 410, beamsplitter 418, and lens 420. The system 400 may
include additional, fewer, or other optical elements than those
shown in FIG. 4. The dichroic mirror 404 is configured to transmit
optical signals of a certain wavelength and reflect optical signals
of a different wavelength. In the example shown, the dichroic
mirror 404 is configured to transmit optical signals from the
treatment laser source 402 (as shown in beam path 403) and reflect
optical signals from the probe laser source 412 (as shown by beam
paths 413, 415). The beamsplitter 418 is configured to transmit a
portion of incident optical signals and reflect the remaining
portion of optical signals. For instance, the beamsplitter 418 is
configured to transmit a portion of the optical signals from the
probe laser source 412 (as shown in beam path 413) and reflect
another portion of those signals upward (not shown in FIG. 4 for
the sake of clarity).
[0032] In operation, optical signals from the treatment laser
source 402 are directed along the beam path 403 toward the optical
fiber 408 and optical signals from the probe laser source 412 are
directed along the beam path 413 toward the optical fiber 408. The
optical fiber 408 directs the respective optical signals from the
laser sources 402, 412 toward the terminating optical element 410.
In some embodiments, terminating optical element 410 and at least a
portion of the optical fiber 408 are located in a surgical laser
probe (e.g., the probe 106 of FIG. 1 or the probe 200 of FIG. 2).
For example, the terminating optical element may be a GRIN lens or
other type of optical element at a distal end of a laser probe tip.
The lens 406 (or other optical elements) may be used to focus the
optical signals into the optical fiber 408.
[0033] When blood or another type of contaminant is located on the
terminating optical element 410, the optical signals from the probe
laser source 412 may be reflected back along the beam path 415
toward the detector 422 (reflected by the beamsplitter 418 and
focused by the lens 420 as shown). The detector 422 may include a
photodetector that receives the reflected optical signals and
generates electrical signals based on the received optical signals.
The detector 422 may then provide those electrical signals to the
control system 424 (indirectly as shown, or directly in some
embodiments), which analyzes the signals to detect whether an
occlusion is present. If an occlusion is detected, then the control
system 424 may disable the treatment laser source 402 before any
overheating may occur.
[0034] In the example shown, a function generator 414 is
communicably coupled to the probe laser source 412. The function
generator 414 generates modulation signals that are provided to the
probe laser source 412 and operate to modulate the optical signals
generated by the probe laser source 412. By modulating the optical
signals generated by the probe laser source 412, the optical
signals reflected from the terminating optical element may be
differentiated from other optical signals that may be received at
the detector 422. The system 400 also includes a lock-in amplifier
416 that is communicably coupled to the detector 422 and the
function generator 414. The lock-in amplifier 416 may be configured
to extract, using the known modulation signal from the function
generator 414, electrical signals from the detector 422 that are
based on the reflected optical signals from the probe laser source
412. The extracted signals may be referred to as "reflected
signals" and may be provided to the control system 424. For
example, the lock-in amplifier 416 may filter the reflected signals
from the signals provided by the detector 422 based on the
modulation signal.
[0035] The control system 424 may then make a determination as to
whether to disable the treatment laser source 402 based on the
signals provided by the lock-in amplifier 416. The determination
may be made by any suitable means based on the beam strength of the
reflected optical signals from the probe laser source 412. For
example, in some implementations, the determination may be made
based on a threshold value, wherein a magnitude of the reflected
signals is compared with a threshold value. If the magnitude is
above the threshold value, then the control system 424 may disable
the treatment laser source 402. Otherwise, if the magnitude of the
reflected signals is below the threshold value, the control system
424 may continue operation of the treatment laser source 402. In
other implementations, the control system 424 may make its
determination based on additional or other factors.
[0036] The example control system 424 includes a processor 426 and
memory 428. The example processor 426 executes instructions, for
example, to generate output data based on data inputs. The
instructions can include programs, codes, scripts, or other types
of data stored in memory. Additionally, or alternatively, the
instructions can be encoded as pre-programmed or re-programmable
logic circuits, logic gates, or other types of hardware or firmware
components. The processor 426 may be or include a general-purpose
microprocessor, as a specialized co-processor or another type of
data processing apparatus. In some cases, the processor 426 may be
configured to execute or interpret software, scripts, programs,
functions, executables, or other instructions stored in the memory
428 to perform one or more functions or operations as described
herein (e.g., those shown in FIG. 5 and described below). In some
instances, the processor 426 includes multiple processors.
[0037] The example memory 428 includes one or more
computer-readable media. For example, the memory 428 may include a
volatile memory device, a non-volatile memory device, or a
combination thereof. The memory 428 can include one or more
read-only memory devices, random-access memory devices, buffer
memory devices, or a combination of these and other types of memory
devices. The memory 428 may store instructions that are executable
by the processor 426.
[0038] In some instances, the control system 424 may be implemented
in another manner. For instance, the control system 424 may be
implemented as an FPGA (field programmable gate array) or an ASIC
(application specific integrated circuit).
[0039] FIG. 5 is a flow diagram of an example process for sensing
occlusions in an optical system, such as in a laser probe of an
ophthalmic surgical system. Operations in the example process 500
may be performed by components of an ophthalmic surgical system
(e.g., the ophthalmic surgical system 100 of FIG. 1 or the system
400 of FIG. 4). For ease of explanation, certain operations in the
process 500 are discussed below with respect to terminology of
components of the system 400 of FIG. 4. However, it will be
understood that the operations of process 500 may be performed by
another type of apparatus that includes a data processing apparatus
or logic.
[0040] At 502, a control system (e.g., control system 424) causes,
directly or indirectly, generation of probe optical signals by a
probe laser source (e.g., probe laser source 412). The probe laser
source may be configured to generate optical signals that are
outside of the absorption spectrum of a contaminant to be sensed.
For instance, where blood occlusions are to be detected, the probe
optical signals may have a wavelength between 600-700 nm or between
800-900 nm. In some embodiments, the probe optical signals may be
modulated based on a modulation signal generated by a function
generator (e.g., function generator 414). The modulation signal may
be used, as described below, to differentiate signals caused by
reflections of the probe optical signals and signals caused by
other optical signals received at a detector. In some cases, the
function generator may directly cause generation of the probe
optical signals by driving a laser diode of the probe laser
source.
[0041] At 504, the control system receives signals generated by an
optical detector. In some cases, the optical detector includes a
photodetector and the signals received at 504 may be electrical
signals generated by the photodetector based on optical signals
received by the photodetector.
[0042] At 506, the control system determines whether reflection
signals associated with reflections of the probe optical signals
are present in the signals received at 504. In some cases,
detection of the reflection signals may be based on the modulation
signal used to modulate the probe optical signals. For instance, a
lock-in amplifier (e.g., lock-in amplifier 416) may be used to
extract or filter reflection signals caused by the reflected probe
optical signals from the signals received from the optical detector
at 504. The control system may determine whether reflection signals
are present at 506 based on a threshold value, as described above,
or in another manner.
[0043] If the control system determines that reflection signals are
determined to be present at 506, then at 508, the control system
disables a treatment laser source (e.g., treatment laser source
402). This may include sending a "kill" signal to the treatment
laser source, disabling power to the treatment laser source,
physically blocking transmission of optical signals from the
treatment laser source (e.g., using a shutter), or disabling the
treatment laser source in another manner. In some embodiments, an
alert, such as an audible alert, may also be generated in response
to detection of the reflection signals at 506. If no reflection
signals are determined to be present at 506, then the process 500
may be repeated.
[0044] The example process 500 may include additional or different
operations, and the operations may be performed in the order shown
or in another order. In some cases, one or more of the operations
shown in FIG. 5 are implemented as processes that include multiple
operations, sub-processes, or other types of routines. In some
cases, operations can be combined, performed in another order,
performed in parallel, iterated, or otherwise repeated or performed
another manner.
[0045] Some of the subject matter and operations described in this
specification can be implemented in digital electronic circuitry,
or in computer software, firmware, or hardware, including the
structures disclosed in this specification and their structural
equivalents, or in combinations of one or more of them. Some of the
subject matter described in this specification can be implemented
as one or more computer programs, i.e., one or more modules of
computer program instructions, encoded on a computer-readable
storage medium for execution by, or to control the operation of,
data-processing apparatus. A computer-readable storage medium can
be, or can be included in, a computer-readable storage device, a
computer-readable storage substrate, a random or serial access
memory array or device, or a combination of one or more of them.
Moreover, while a computer-readable storage medium is not a
propagated signal, a computer-readable storage medium can be a
source or destination of computer program instructions encoded in
an artificially generated propagated signal. The computer-readable
storage medium can also be, or be included in, one or more separate
physical components or media (e.g., multiple CDs, disks, or other
storage devices).
[0046] Some of the operations described in this specification can
be implemented as operations performed by a data processing
apparatus on data stored on one or more computer-readable storage
devices or received from other sources. The term "data processing
apparatus" encompasses all kinds of apparatus, devices, and
machines for processing data, including by way of example a
programmable processor, a computer, a system on a chip, or multiple
ones, or combinations, of the foregoing. The apparatus can include
special purpose logic circuitry, e.g., an FPGA (field programmable
gate array) or an ASIC (application specific integrated circuit).
The apparatus can also include, in addition to hardware, code that
creates an execution environment for the computer program in
question, e.g., code that constitutes processor firmware, a
protocol stack, a database management system, an operating system,
a cross-platform runtime environment, a virtual machine, or a
combination of one or more of them.
[0047] A computer system may include a single computing device, or
multiple computers that operate in proximity or generally remote
from each other and typically interact through a communication
network. Examples of communication networks include a local area
network ("LAN") and a wide area network ("WAN"), an inter-network
(e.g., the Internet), a network comprising a satellite link, and
peer-to-peer networks (e.g., ad hoc peer-to-peer networks). The
computer system may include one or more data processing apparatuses
coupled to computer-readable media storing one or more computer
programs that may be executed by the one or more data processing
apparatuses, and one or more interfaces for communicating with
other computer systems.
[0048] A computer program (also known as a program, software,
software application, script, or code) can be written in any form
of programming language, including compiled or interpreted
languages, declarative or procedural languages, and it can be
deployed in any form, including as a stand-alone program or as a
module, component, subroutine, object, or other unit suitable for
use in a computing environment. A computer program may, but need
not, correspond to a file in a file system. A program can be stored
in a portion of a file that holds other programs or data (e.g., one
or more scripts stored in a markup language document), in a single
file dedicated to the program, or in multiple coordinated files
(e.g., files that store one or more modules, sub programs, or
portions of code). A computer program can be deployed to be
executed on one computer or on multiple computers that are located
at one site or distributed across multiple sites and interconnected
by a communication network.
[0049] Embodiments of the present disclosure provide systems and
methods for sensing occlusions in optical systems, such as in laser
probes of an ophthalmic surgical system, that may overcome
limitations of conventional systems and methods. It will be
appreciated that above-disclosed and other features and functions,
or alternatives thereof, may be desirably combined into many other
different systems or applications in accordance with the
disclosure. It will also be appreciated that various presently
unforeseen or unanticipated alternatives, modifications,
variations, or improvements therein may be subsequently made by
those skilled in the art which alternatives, variations and
improvements are also intended to be encompassed by the following
claims.
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