U.S. patent application number 14/529861 was filed with the patent office on 2015-06-11 for ophthalmic laser system.
This patent application is currently assigned to ELLEX MEDICAL PTY LTD. The applicant listed for this patent is ELLEX MEDICAL PTY LTD. Invention is credited to Dmitri Feklistov, Malcolm Plunkett.
Application Number | 20150157506 14/529861 |
Document ID | / |
Family ID | 28047222 |
Filed Date | 2015-06-11 |
United States Patent
Application |
20150157506 |
Kind Code |
A1 |
Feklistov; Dmitri ; et
al. |
June 11, 2015 |
Ophthalmic Laser System
Abstract
An ophthalmic laser system generating a first beam at a
wavelength suitable for performing selective laser trabeculoplasty
and selectively generating a second beam at a wavelength suitable
for performing secondary cataract surgery procedures. The laser
system is able to select between directing the first beam or the
second beam to the eye of a patient. The first beam is suitably
generated at 1064 nm from a Nd:YAG laser and the second beam is
frequency doubled to 532 nm in a KTP doubling crystal.
Inventors: |
Feklistov; Dmitri;
(Adelaide, AU) ; Plunkett; Malcolm; (Adelaide,
AU) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ELLEX MEDICAL PTY LTD |
ADELAIDE |
|
AU |
|
|
Assignee: |
ELLEX MEDICAL PTY LTD
ADELAIDE
AU
|
Family ID: |
28047222 |
Appl. No.: |
14/529861 |
Filed: |
October 31, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14148683 |
Jan 6, 2014 |
8876808 |
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14529861 |
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10847062 |
May 17, 2004 |
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14148683 |
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PCT/AU2003/001224 |
Sep 18, 2003 |
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10847062 |
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Current U.S.
Class: |
606/6 |
Current CPC
Class: |
A61F 9/00821 20130101;
A61F 9/008 20130101; A61F 9/00823 20130101; A61B 2018/207 20130101;
A61F 2009/00891 20130101; A61F 9/0084 20130101; A61F 2009/00887
20130101; A61F 2009/00868 20130101 |
International
Class: |
A61F 9/008 20060101
A61F009/008 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 18, 2002 |
AU |
2002951467 |
Claims
1. An ophthalmic laser system, comprising: a laser module adapted
to produce a beam of short pulses of radiation with high energy
density at a first wavelength; a first beam path incorporating an
attenuator, beam shaping optics, and means for directing the beam
at said first wavelength to an eye of a patient; a second beam path
incorporating a frequency conversion module that converts the beam
at the first wavelength to a beam at a second wavelength, an
attenuator, and means for directing the beam at said second
wavelength to the eye of the patient; and extracavity deflecting
means for selectively deflecting the beam at said first wavelength
into the second beam path, said extracavity deflecting means being
operable between a first position in which the beam at said first
wavelength follows the first beam path and a second position in
which the beam at said first wavelength is deflected to said second
beam path.
2. The ophthalmic laser system of claim 1, wherein the extracavity
deflecting means comprises a half wave plate and polarizer.
3. The ophthalmic laser system of claim 1, wherein said half wave
plate is rotatable by motorized means.
4. The ophthalmic laser system of claim 1, wherein the half wave
plate is remotely operable.
5. The ophthalmic laser system of claim 1, further comprising means
for remotely selecting between said first beam path and said second
beam path.
6. The ophthalmic laser system of claim 1, wherein the laser module
is a flashlamp pumped, solid state laser.
7. The ophthalmic laser system of claim 1, wherein the laser module
is a Nd:YAG laser producing said beam at said first wavelength at a
wavelength of 1064 nm, and said beam at said second wavelength is
frequency-doubled to 532 nm.
8. The ophthalmic laser system of claim 1, wherein said beam
shaping optics in said first beam path comprises a beam
expander.
9. The ophthalmic laser system of claim 1, wherein said first beam
path further incorporates an energy monitor system.
10. The ophthalmic laser system of claim 1, further comprising an
aiming laser providing a targeting reference for said beam at said
first wavelength.
11. The ophthalmic laser system of claim 1, wherein the frequency
conversion module comprises a KTP doubling crystal or similar
frequency conversion device.
12. The ophthalmic laser system of claim 1, wherein said second
beam path further incorporates an energy monitor system.
13. The ophthalmic laser system of claim 1, wherein said second
beam path further incorporates beam shaping optics.
14. The ophthalmic laser system of claim 1, further comprising an
aiming laser providing a targeting reference for said beam at said
second wavelength.
15. An ophthalmic laser system for selective treatment of glaucoma
and/or secondary cataracts, comprising: a laser module adapted to
produce a beam of short pulses of radiation with high energy
density at a first wavelength; a first beam path incorporating an
attenuator, beam shaping optics, and means for directing the beam
at said first wavelength to an eye of a patient for secondary
cataract treatment; a second beam path incorporating a frequency
conversion module that converts the beam at the first wavelength to
a beam at a second wavelength, an attenuator, and means for
directing the beam at said second wavelength to the eye of the
patient for glaucoma treatment; extracavity deflecting means for
selectively deflecting the beam at said first wavelength into the
second beam path, said means being operable between a first
position in which the beam at said first wavelength follows the
first beam path and a second position in which the beam at said
first wavelength is deflected to said second beam path; and means
for remotely selecting between said first beam path for secondary
cataract treatment and said second beam path for glaucoma
treatment.
16. An ophthalmic laser system, comprising: a laser module adapted
to produce a beam of short pulses of radiation with high energy
density at a first wavelength; a first beam path incorporating an
attenuator, beam shaping optics, and a mirror that directs the beam
at said first wavelength to an eye of a patient; a second beam path
incorporating a frequency conversion module that converts the beam
at the first wavelength to a beam at a second wavelength, an
attenuator, and a mirror that directs the beam at said second
wavelength to the eye of the patient; and extracavity deflecting
means comprising a half wave plate and polarizer combination that
selectively deflects the beam at said first wavelength into the
second beam path, said extracavity deflecting means being operable
between a first position in which the beam at said first wavelength
follows the first beam path and a second position in which the beam
at said first wavelength is deflected to said second beam path.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S.
application Ser. No. 14/148,683 filed Jan. 6, 2014, which is a
divisional of U.S. application Ser. No. 10/847,062 filed May 17,
2004 (each incorporated by reference in its entirety for all
purposes), which is a continuation-in-part of PCT/AU2003/001224
filed Sep. 18, 2003, which claims priority to AU2002951467 filed
Sep. 18, 2002.
FIELD OF THE INVENTION
[0002] This invention relates to a treatment laser instrument
designed for use by ophthalmologists for performing selective laser
trabeculoplasty (for treating glaucoma) procedures and secondary
cataract surgery procedures. In particular, the invention relates
to an ophthalmic laser system that can operate effectively in both
the infrared region (for secondary cataract treatment) and other
regions, such as the green region (for glaucoma treatment
BACKGROUND TO THE INVENTION
[0003] Glaucoma (abnormal intra-ocular pressure) is a major eye
problem that leads to blindness in a significant percentage of the
world population. Glaucoma is the most common cause of blindness in
the world today. The established technique for treating glaucoma is
drug based. Alternative treatment modalities have been sought to
avoid the side effects and non-specificity associated with drug
based treatments. Over the past few years a technique known as
selective laser trabeculoplasty (SLT) has been invented by Latina.
The technique is described in U.S. Pat. No. 5,549,596, assigned to
The General Hospital Corporation. Latina describes the use of a
frequency doubled Nd:YAG laser for the SLT procedure.
[0004] SLT is an improvement over a previously used technique
referred to as argon laser trabeculoplasty (ALT). ALT uses a
thermal effect to coagulate loose trabecular meshwork cells
believed to be present in patients with glaucoma. Because an Argon
laser is essentially CW (if pulsed, the pulse duration is long
compared to thermal transfer mechanisms) there is significant heat
transfer into surrounding tissue. This results in damage to
otherwise healthy cells. It has been found that the ALT process can
only be used once or twice before collateral damage prevents any
further benefit from ALT treatment.
[0005] In contrast, SLT utilizes a pulsed laser (the pulse duration
is short compared to thermal effects) so there is minimal heat
transfer to surrounding tissue. SLT has been found to be
repeatable, unlike the ALT process.
[0006] A detailed discussion of the SLT modality and a comparison
with ALT is found in Ocular Surgery News published 1 Mar. 2000.
[0007] Another very common ophthalmic treatment is secondary
cataract surgery. The most effective laser for secondary cataract
surgery is a Nd:YAG laser operating at 1064 nm. These lasers are
typically referred to as photodisruptors as they act by non-thermal
mechanisms to cut tissue. A typical ophthalmic laser system
consists of the laser head and a beam delivery system coupled to a
conventional slit lamp assembly. A typical laser system for
secondary cataract surgery is described in U.S. Pat. No.
6,325,792.
[0008] At present, two separate laser systems are necessary to
perform the procedures for treating the two most common eye
problems.
[0009] An attempt to address the problem of requiring multiple
lasers for different treatment modalities has been described in
U.S. Pat. No. 6,066,127. This patent describes a system for
changing the laser cavity between a pulsed configuration and a
continuous wave configuration by introducing a movable intracavity
element. This approach is problematic because it is extremely
difficult to maintain optimum alignment of the laser cavity with a
movable intracavity element.
[0010] A better solution is required.
SUMMARY OF THE INVENTION
[0011] In one form, although it need not be the only or indeed the
broadest form, the invention resides in an ophthalmic laser system
comprising:
[0012] a laser module producing a beam of short pulses of radiation
with high energy density at a first wavelength;
[0013] a first beam path incorporating an attenuator, beam shaping
optics, and means for directing the beam at said first wavelength
to an eye of a patient;
[0014] a second beam path incorporating a frequency conversion
module that converts the beam at the first wavelength to a beam at
a second wavelength, an attenuator, and means for directing the
beam at said second wavelength to the eye of the patient; and
[0015] extracavity deflecting means for selectively deflecting the
beam at said first wavelength into the second beam path, said means
being operable between a first position in which the beam at said
first wavelength follows the first beam path and a second position
in which the beam at said first wavelength is deflected to said
second beam path.
[0016] Preferably the beam at said first wavelength is a 1064 nm
beam produced by a Nd:YAG laser, and said beam at said second
wavelength is frequency-doubled to 532 nm. The beam is suitably
doubled by a KTP doubling crystal or similar frequency doubling
device.
[0017] Preferably the extracavity deflecting means comprises a half
wave plate and polarizer. The half wave plate is suitably remotely
operable, such as by a servo motor or solenoid.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] To assist in understanding the invention, preferred
embodiments will be described with reference to the following
figures in which:
[0019] FIG. 1 shows a general schematic view of an ophthalmic laser
system;
[0020] FIG. 2 shows a schematic side view of the photodisruptor
optical system of the ophthalmic laser system in FIG. 1; and
[0021] FIG. 3 shows a schematic view of the SLT optical system of
the ophthalmic laser system in FIG. 1;
[0022] FIG. 4 shows a schematic view of the energy monitor
system;
[0023] FIG. 5 shows a schematic of the beam-shaping module of the
photodisruptor optical system;
[0024] FIG. 6 shows a schematic of the beam-shaping module of the
SLT optical system; and
[0025] FIG. 7 shows an external view of an ophthalmic treatment
device incorporating the ophthalmic laser system.
DETAILED DESCRIPTION
[0026] Referring to FIG. 1, there is shown an embodiment of an
ophthalmic laser system 1 useful for treating glaucoma and
secondary cataracts. The system is comprised of a laser module 2, a
photodisruptor optical system 3 and SLT optical system 4, as shown
separately in FIGS. 2 and 3.
[0027] The ophthalmic laser system 1 of the present invention
combines the photodisruptor optical system 3 and SLT optical system
4 into one integral unit, which uses a single laser module 2. The
laser module 2 is a Q switched Nd:YAG laser operating in the
infrared spectrum. The laser emits a beam at 1064 nm wavelength,
having a pulse width of less than 5 nsec. Other laser modules (such
as Nd:YLF, Yb:YAG, etc) will also be suitable as will be readily
apparent to persons skilled in the art.
[0028] Referring now to FIG. 1 and FIG. 2, a pulsed beam from the
laser module 2 is attenuated at attenuator/beam steering module 5.
An energy monitor system 6 measures the energy in each pulse. For
the photodisruptor optical system the desired energy density is
0.3-10 mj in an 8-10 .mu.m spot. A half wave plate 7 within the
attenuator/beam steering module 5 is adjusted to regulate the
intensity of the pulsed beam in the photodisruptor optical system
3. A polarizing plate 8 may deflect the pulsed beam to the SLT
optical system 4 depending on the orientation of the half wave
plate 7. The function of the attenuator/beam steering module 5 will
be described in more detail later.
[0029] Beam shaping optical module 9 expands the pulsed beam before
it travels up to the folding mirror module 10. The expanded beam is
then focused by objective lens 13 to produce the 8-10 .mu.m beam
waist at the treatment site which is required to produce
photodisruption. An aiming laser module 11 provides a continuous,
visible laser beam that is split into two beams and deflected by
folding mirror module 10 to give a targeting reference for the
treatment beam. These two aiming laser beams converge with the
pulsed treatment beam at the target site in a patient's eye 12 via
objective lens 13. An operator 14 views the patient's eye 12
through the folding mirror module 10. A safety filter 15 protects
the eye of the operator. The folding mirrors 10a, 10b are
positioned so that the viewing axis of the operator is not impeded.
It will be appreciated by those skilled in the art that the mirrors
may be replaced by prisms or other suitable beam steering
optics.
[0030] Referring to FIG. 3, the SLT optical system 4 comprises a
mirror 16 that directs a deflected pulsed beam from the polarizing
plate 8 in the attenuator/beam steering module 5 of FIG. 1 to the
frequency conversion module, which is a frequency doubling module
17 in the preferred embodiment. To maximize frequency doubling
efficiency the entire pulsed beam is deflected by
attenuator/beamsteering module 5. The frequency doubling module 17
converts the output of the laser module to half the wavelength so
that the output of the SLT optical system is in the visible
spectrum. For the particular embodiment the Nd:YAG laser module
operates in the near infrared at 1064 nm which is frequency doubled
to 532 nm, which is in the green region of the visible spectrum.
The green pulsed beam is effective in treating glaucoma in
patients.
[0031] The pulsed green beam may be attenuated at the SLT
attenuator 18 to regulate the energy in the pulsed green beam. An
energy monitor system 19 measures the energy in each pulse. For the
SLT process the desired energy density is 0.01-5 J/cm.sup.2, as
described by Latina.
[0032] Other wavelengths may be suitable for other ophthalmic
applications in which case the frequency conversion module may
triple or quadruple the fundamental frequency. In some applications
it may even be desirable to use a tunable frequency conversion
module, such as an optical parametric oscillator.
[0033] A beam shaping module 20 adjusts the beam profile to provide
an even energy distribution at the treatment plane. The green beam
then travels to a second folding mirror module 21. A second aiming
laser module 22 provides a single aiming laser beam which is
deflected by the second folding mirror 21 and transmitted through
folding mirror module 10 and objective lens 13, as shown in FIG. 1.
The continuous visible laser aiming beam generated by the second
aiming laser module 22 coincides with the green pulsed beam at the
target site in a patient's eye 12 via objective lens 13 and contact
lens 23. As mentioned earlier, the mirror could be replaced by
prisms or other suitable optical elements.
[0034] Although two separate aiming laser modules 11, 22 are
described, it will be appreciated that a single aiming laser module
could be used with appropriate beam deflecting optics, such as a
mirror, to direct the aiming laser beam through folding mirror
module 10 for off-axis illumination or folding mirror module 21 for
on-axis illumination.
[0035] The present invention provides an ophthalmic laser system
for treating glaucoma and secondary cataract conditions, using a
single laser source. The present invention integrates two known
laser treatment techniques, SLT and photodisruptor, into one
integrated system.
[0036] The method used to direct the laser beam from the laser
module 2 to the photodisruptor optical system 3 or the SLT optical
system 4 will now be described in detail. Referring to FIG. 1, the
attenuator/beam steering module 5 first receives a pulsed and
linearly polarized beam from laser module 2 at half wave plate 7.
The pulsed beam passes through the half wave plate to the
polarizing plate 8.
[0037] The orientation of the half wave plate 7 determines the
amount of the pulsed beam that is passed through the polarizing
plate 8 into the photodisruptor optical system 3. The orientation
of the half wave plate 7 can be adjusted by motorized means so that
the polarization angle of the component of the resulting beam which
coincides with the transmission characteristic of the polarizing
plate 8 will be passed through to the beam shaping module 9.
However, as the half wave plate 7 is rotated, the polarization of
the beam is changed. Accordingly, only some portion of the beam
will be transmitted.
[0038] In the photodisruptor mode for treating secondary cataracts,
the half wave plate 7 is rotated to permit transmission of the
required pulsed laser beam emitted from the laser module 2. If the
SLT mode is required, the half wave plate 7 is oriented so that all
the beam is reflected from the polarising plate 8 to the mirror 16
of the SLT optical system 4.
[0039] The ophthalmic laser system described above allows an
operator to select the mode of treatment to be administered to a
patient, simply by choosing one of two optical paths. A simple
adjustment of the half wave plate 7 determines whether a SLT or a
photodisruptor mode is chosen for treating glaucoma or secondary
cataracts respectively. The adjustment of the half wave plate can
be motorized so the selection of treatment modality may be by
simple button selection.
[0040] It will be appreciated that the directing of the Nd:YAG
laser beam into the photodisruptor module path or the SLT module
path can be achieved by any suitable means (such as a mirror) but
the use of a polarizing plate is preferred.
[0041] As mentioned above, each optical system includes an energy
monitor system in the preferred embodiment. A schematic of the
components of an energy monitor system is shown in FIG. 4. A small
percentage of the beam is split by optic plate 24 towards a
photodiode 25. A number of filters and diffusers 26 are positioned
in front of the photodiode 25.
[0042] As seen in FIG. 2, once the pulse beam is attenuated to the
desired power, the beam is further conditioned by beam shaping
optical module 9. The beam shaping optical module 9 is shown in
more detail in FIG. 5. Lenses 27 and 28 form a beam expander which
expands the 3 mm diameter beam from the laser module 2 by ten
times. The expanded beam is reflected into the optical viewing path
by the folding mirror 10 which uses a wavelength selective coating
to avoid blocking of the viewing path. The beam from folding mirror
10 is then focused by objective lens 13 to produce the 8-10 .mu.m
beam waist at the treatment site which is required to produce
photodisruption.
[0043] Referring to FIG. 6, the SLT beam is conditioned by beam
shaping module 20 before the folding mirror module 21. The beam
shaping module 20 consists of two lenses 28, 29 that form a beam
expander that is designed to produce a well defined treatment spot
with an even energy distribution.
[0044] The invention is conveniently embodied in an ophthalmic
treatment device of the type shown in FIG. 7. The treatment device
30 is of the conventional form having a slit lamp assembly 31
mounted on a table 32 which is in turn mounted on a height
adjusting pedestal 33. The slit lamp assembly 31 is movable with
respect to the table 32 +using joystick 34, in conventional manner.
The ophthalmic laser system is mounted in the body 35 of the slit
lamp assembly 31. This is achieved by using a compact laser cavity
and careful placement of optical components.
[0045] The ophthalmic laser system is controlled by a control panel
36. The joy stick 34 may incorporate a fire button 37 to fire the
laser, or alternatively a foot pedal (not shown) may be used.
[0046] The invention has been described with reference to one
particular embodiment however, it should be noted that other
embodiments are envisaged within the spirit and scope of the
invention. For instance, one or two aiming lasers could be used,
the photodisruptor or SLT beam path could be selected by a movable
mirror, or the beam shaping optics could have a different
configuration.
* * * * *