U.S. patent application number 14/213492 was filed with the patent office on 2014-10-23 for systems and methods for affecting the biomechanical properties of connective tissue.
The applicant listed for this patent is AnnMarie Hipsley. Invention is credited to AnnMarie Hipsley.
Application Number | 20140316388 14/213492 |
Document ID | / |
Family ID | 51537762 |
Filed Date | 2014-10-23 |
United States Patent
Application |
20140316388 |
Kind Code |
A1 |
Hipsley; AnnMarie |
October 23, 2014 |
SYSTEMS AND METHODS FOR AFFECTING THE BIOMECHANICAL PROPERTIES OF
CONNECTIVE TISSUE
Abstract
A device for delivering ablative medical treatments to improve
biomechanics comprising a laser for generating a beam of laser
radiation used in ablative medical treatments to improve
biomechanics, a housing, a controller within the housing, in
communication with the laser and operable to control dosimetry of
the beam of laser radiation in application to a target material, a
lens operable to focus the beam of laser radiation onto a target
material, and a power source operable to provide power to the laser
and controller.
Inventors: |
Hipsley; AnnMarie; (Silver
Lake, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hipsley; AnnMarie |
Silver Lake |
OH |
US |
|
|
Family ID: |
51537762 |
Appl. No.: |
14/213492 |
Filed: |
March 14, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61798379 |
Mar 15, 2013 |
|
|
|
Current U.S.
Class: |
606/4 |
Current CPC
Class: |
A61F 2009/00895
20130101; A61F 9/00802 20130101; A61F 2009/00865 20130101; A61B
2018/00577 20130101; A61F 2009/00844 20130101; A61B 18/20 20130101;
A61F 2009/00897 20130101; A61F 2009/00851 20130101; A61F 2009/00872
20130101; A61F 9/00838 20130101 |
Class at
Publication: |
606/4 |
International
Class: |
A61F 9/008 20060101
A61F009/008 |
Claims
1. A device for delivering ablative medical treatments to improve
biomechanics comprising: a laser for generating a beam of laser
radiation used in ablative medical treatments to improve
biomechanics; a housing; a controller within the housing, in
communication with the laser and operable to control dosimetry of
the beam of laser radiation in application to a target material; a
lens operable to focus the beam of laser radiation onto a target
material; and a power source operable to provide power to the laser
and controller.
2. The device for delivering ablative medical treatments to improve
biomechanics of claim 1, further comprising: a scanner operable to
monitor a position of the laser during the medical treatment and
send position information to a processor; the processor operable to
receive and use the position information to calculate whether a
treatment location has moved; the processor operable to reconfigure
the position of the laser if the treatment location has moved; and
the processor operable to stop the medical treatment if the
treatment location has moved a distance greater than a preselected
threshold distance.
3. The device for delivering ablative medical treatments to improve
biomechanics of claim 1, further comprising: a scanner operable to
monitor a depth of an ablation during the medical treatment and
send depth information to a processor; the processor operable to
receive and use the depth information to calculate whether a
treatment depth has reached a threshold; the processor operable to
allow continuation of the medical procedure if the treatment depth
has not reached the threshold; and the processor operable to stop
the medical treatment if the treatment depth has reached or
exceeded the threshold.
4. The device for delivery ablative medical treatments to improve
biomechanics of claim 1, wherein the laser further comprises a
flash lamp, a high powered diode, and an optical pump.
5. A method of delivering ablative medical treatments to improve
biomechanics comprising: using a laser to generate a treatment beam
in a treatment to improve biomechanics; wherein a controller, in
electrical communication with the laser, is used to control
dosimetry of the treatment beam in application to a target
material; wherein a lens is used to focus the treatment beam onto
the target material; and wherein a power source is used to provide
power to the laser and the controller.
6. The method of delivering ablative medical treatments to improve
biomechanics of claim 5, further comprising: using a scanner to
monitor a position of the treatment beam during the treatment and
send position information to a processor; wherein the processor
receives and uses the position information to calculate whether a
treatment location has moved; wherein the processor reconfigures
the position of the treatment beam if the treatment location has
moved; and wherein the processor halts the medical treatment if the
treatment location has moved a distance greater than a preselected
threshold distance.
7. The method of delivering ablative medical treatments to improve
biomechanics of claim 5, further comprising: using a scanner to
monitor a depth of an ablation during the treatment and sending
depth information to a processor; wherein the processor receives
and uses the depth information to calculate whether a treatment
depth has reached a threshold; wherein the processor allows
continuation of the procedure if the treatment depth has not
reached the threshold; and wherein the processor halts the
treatment if the treatment depth has reached or exceeded the
threshold.
8. The method of delivering ablative medical treatments to improve
biomechanics of claim 5, wherein using a laser further comprises
using a flash lamp, a high powered diode, and an optical pump.
9. A system of ablating biological tissue to improve biomechanics
comprising: performing an ablating procedure on a biological tissue
in a pattern while monitoring the ablating procedure.
10. The system of ablating biological tissue to improve
biomechanics of claim 9, wherein the ablating procedure is
performed using a laser.
11. The system of ablating biological tissue to improve
biomechanics of claim 9, wherein monitoring the ablating procedure
is performed using OCT (optical coherence tomography).
12. The system of ablating biological tissue to improve
biomechanics of claim 11, wherein using OCT further comprises
monitoring a depth of ablation.
13. The system of ablating biological tissue to improve
biomechanics of claim 11, wherein the pattern further comprises a
golden spiral.
14. The system of ablating biological tissue to improve
biomechanics of claim 9, wherein monitoring the ablating procedure
uses feature identification and positional tracking.
15. The system of ablating biological tissue to improve
biomechanics of claim 9, wherein the biological tissue is scleral
tissue.
16. The system of ablating biological tissue to improve
biomechanics of claim 9, wherein improving biomechanics includes
improving corneal accommodation.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Appl. No.
61/798,379, filed Mar. 15, 2013, and is related to the following
U.S. Appl. Nos.: U.S. Appl. No. 60/662,026, filed Mar. 15, 2005;
U.S. application Ser. No. 11/376,969, filed Mar. 15, 2006; U.S.
Appl. No. 60/842,270, filed Sep. 5, 2006; U.S. Appl. No.
60/865,314, filed Nov. 10, 2006; U.S. Appl. No. 60/857,821, filed
Nov. 10, 2006; U.S. application Ser. No. 11/850,407, filed Sep. 5,
2007; U.S. application Ser. No. 11/938,489, filed Nov. 12, 2007;
U.S. application Ser. No. 12/958,037, filed Dec. 1, 2010; and U.S.
application Ser. No. 13/342,441, filed Jan. 3, 2012, the entire
contents and disclosures of which are hereby incorporated by
reference.
FIELD
[0002] The subject matter described herein relates generally to
systems and methods for affecting the biomechanical properties of
connective tissue and more specifically, to systems and methods for
treating connective tissue to alter the fundamental and
biomechanical properties of the connective tissue.
BACKGROUND
[0003] Connective tissue is tissue that supports and connects other
tissues and parts of the body. The fundamental and biomechanical
properties of connective tissue, such as scleral tissue of the eye,
may change as it ages. These fundamental and biomechanical tissues
have properties which include, but are not limited to, their
structure, function, immunology, elasticity, shock absorption,
resilience, mechanical dampening, pliability, stiffness, rigidity,
configuration, alignment, deformation, mobility, volume,
biochemistry and molecular genetics of connective tissue proper and
newly metabolized connective tissue. The alterations of these
properties may result in an accumulation of low grade stress/strain
of the connective tissue. This can occur by acute injury or as a
normal gradual process of aging. The alterations of these
properties of connective tissue may change the overall desired
properties of the connective tissue and may also undesirably affect
the surrounding tissues, structures, organs, or systems related to
the connective tissue. Examples of such undesirable affects are
increased tension, loss of flexibility, contracture, fibrosis, or
sclerosis, any of which can prevent the connective tissue or
structures that are related to the connective tissue from
performing their desired function.
[0004] Natural alterations in fundamental and biomechanical
properties, specifically pliability and elasticity of the scleral
tissue of the eye may affect the ability of the eye to focus. These
alterations may be caused by disease or age-related changes to the
tissue. These alterations of the scleral tissue may also contribute
to an increase in intraocular pressure and to the loss of the
contrast sensitivity of the eye or visual field of the eye.
Biomechanical and structural alterations of the sclera may affect
the refractive ability as well as the efficiency of the homeostatic
functions of the eye such as intraocular pressure, aqueous
production, pH, balance, vascular dynamics, metabolism and eye
organ function. Furthermore, alterations of the scleral tissue may
contribute to damage to the mechanoreceptors, photoreceptors, or
sensory receptors in tissue layers and structures that are directly
or indirectly related to the scleral tissue. Additionally,
fundamental and biomechanical alterations of the scleral tissue may
also be a contributing factor in the ability of the cerebral cortex
to process accurate visual stimulus necessary for processing visual
signals into accurate visual perception.
[0005] Presbyopia is a condition which affects focusing ability of
the eye, especially in the elderly. Presbyopia is the loss of
accommodation--the ability to focus through a range of near to far
object. Some causes of presbyopia are considered to be a loss of
elasticity in the crystalline lens and loss of strength in the
ciliary muscles of the eye. Although naturally occurring,
presbyopia affects a person's vision including increased eyestrain,
visibility issues in low or dim lighting, and focusing problems on
small objects. As such, presbyopia causes a loss of
accommodation.
[0006] It is therefore desirable to provide improved systems and
methods for altering the biomechanical properties of connective
tissue having advantages not heretofore taught.
SUMMARY OF THE INVENTION
[0007] Systems and methods for altering the biomechanical
properties of connective tissue are described herein that overcomes
the limitations noted above.
[0008] In general a device for delivering medical treatments is
disclosed which comprises a laser for generating a beam of laser
radiation, a housing, a controller within the housing, in
communication with the laser and operable to control the qualities
of the beam of laser radiation in application to a target material,
a lens operable to focus the beam of laser radiation onto a target
material, and a power source operable to provide power to the laser
and controller.
[0009] Other features and advantages of the present invention will
become apparent from the following more detailed description, taken
in conjunction with the accompanying drawings, which illustrate, by
way of example, the principles of the presently described
invention.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)
[0010] Illustrated in the accompanying drawing(s) is at least one
of the best mode embodiments of the present invention. In such
drawing(s):
[0011] FIG. 1 illustrates an overview of a medical treatment system
using a laser according to an embodiment of the present
invention;
[0012] FIG. 2 illustrates a laser treatment system according to an
embodiment of the present invention;
[0013] FIG. 3 illustrates a laser treatment system according to an
embodiment of the present invention;
[0014] FIG. 3A illustrates a laser treatment system according to an
embodiment of the present invention;
[0015] FIG. 3B illustrates a laser treatment system according to an
embodiment of the present invention;
[0016] FIG. 3C illustrates a camera correction system according to
an embodiment of the present invention;
[0017] FIG. 3D illustrates a flow diagram of a camera-based eye
tracker process according to an embodiment of the present
invention;
[0018] FIG. 3E illustrates a flow diagram for a laser ablation
procedure according to an embodiment of the present invention;
[0019] FIG. 4 illustrates a laser treatment system according to an
embodiment of the present invention;
[0020] FIG. 4A illustrates a laser treatment system including
ablation pore depth according to an embodiment of the present
invention;
[0021] FIG. 4B illustrates a flow diagram of OCT-based depth
control according to an embodiment of the present invention;
[0022] FIG. 5A illustrates a laser treatment system lens placement
according to an embodiment of the present invention;
[0023] FIG. 5B illustrates a laser treatment system lens placement
according to an embodiment of the present invention;
[0024] FIG. 5C illustrates a laser treatment system lens placement
according to an embodiment of the present invention;
[0025] FIG. 6 illustrates a laser treatment system component map
showing relation of related subsystems according to an embodiment
of the present invention;
[0026] FIG. 7 illustrates a laser treatment system according to an
embodiment of the present invention;
[0027] FIG. 8 illustrates an eye treatment map according to an
embodiment of the present invention;
[0028] FIG. 9 illustrates a front view of an pore matrix according
to an embodiment of the present invention;
[0029] FIG. 10 illustrates a front view of pore matrices according
to an embodiment of the present invention;
[0030] FIG. 11 illustrates a rear view of an pore matrix according
to an embodiment of the present invention;
[0031] FIG. 12 illustrates a pore matrix according to an embodiment
of the present invention;
[0032] FIG. 13 illustrates a pore matrix according to an embodiment
of the present invention;
[0033] FIG. 14 illustrates a pore matrix according to an embodiment
of the present invention;
[0034] FIG. 15 illustrates a pore matrix according to an embodiment
of the present invention;
[0035] FIG. 16 illustrates a pore matrix depth according to an
embodiment of the present invention;
[0036] FIG. 17 illustrates a pore matrix depth according to an
embodiment of the present invention;
[0037] FIG. 18 illustrates a pore matrix according to an embodiment
of the present invention;
[0038] FIG. 19 illustrates a pore matrix according to an embodiment
of the present invention;
[0039] FIG. 20 illustrates a pore matrix in spiral form according
to an embodiment of the present invention;
[0040] FIG. 21 illustrates a pore matrix in spiral form according
to an embodiment of the present invention;
[0041] FIG. 22 illustrates a pore matrix in concentric circular
form according to an embodiment of the present invention; and
[0042] FIG. 23 illustrates a pore matrix in interspersed circular
form according to an embodiment of the present invention.
[0043] FIG. 24A illustrates an accommodated and a dis-accommodated
eye in showing muscle movement of the eye.
[0044] FIG. 24B illustrates the three parts of ciliary muscle and
their relation to one another in the eye.
[0045] FIG. 24C shows contraction of ciliary muscle and its effect
on the eye.
[0046] FIG. 25 shows a configuration according to at least one
embodiment of the present invention, where the beam delivery system
scans over the eye in a "goniometric" motion.
[0047] FIG. 26 shows an isotropic linearly elastic material
subjected to tension along the x axis with a Poisson's ratio of
0.5. The cube is unstrained while the rectangle is expanded in the
x direction due to tension and contracted in the y and z
directions.
DETAILED DESCRIPTION
[0048] The above described figures illustrate the described
invention in at least one of its preferred, best mode embodiments,
which is further defined in detail in the following description.
Those having ordinary skill in the art may be able to make
alterations and modifications to what is described herein without
departing from its spirit and scope. While this invention is
susceptible to embodiment in many different forms, there is shown
in the drawings and will herein be described in detail a preferred
embodiment of the invention with the understanding that the present
disclosure is to be considered as an exemplification of the
principles of the invention and is not intended to limit the broad
aspect of the invention to the embodiment illustrated. Therefore,
it should be understood that what is illustrated is set forth only
for the purposes of example and should not be taken as a limitation
on the scope of the present invention, since the scope of the
present disclosure will be limited only by the appended claims.
[0049] As used herein and in the appended claims, the singular
forms "a", "an", and "the" include plural referents unless the
context clearly dictates otherwise.
[0050] The publications discussed herein are provided solely for
their disclosure prior to the filing date of the present
application. Nothing herein is to be construed as an admission that
the present disclosure is not entitled to antedate such publication
by virtue of prior disclosure. Further, the dates of publication
provided may be different from the actual publication dates which
may need to be independently confirmed.
[0051] It should be noted that all features, elements, components,
functions, and steps described with respect to any embodiment
provided herein are intended to be freely combinable and
substitutable with those from any other embodiment. If a certain
feature, element, component, function, or step is described with
respect to only one embodiment, then it should be understood that
that feature, element, component, function, or step can be used
with every other embodiment described herein unless explicitly
stated otherwise. This paragraph therefore serves as antecedent
basis and written support for the introduction of claims, at any
time, that combine features, elements, components, functions, and
steps from different embodiments, or that substitute features,
elements, components, functions, and steps from one embodiment with
those of another, even if the following description does not
explicitly state, in a particular instance, that such combinations
or substitutions are possible. It is explicitly acknowledged that
express recitation of every possible combination and substitution
is overly burdensome, especially given that the permissibility of
each and every such combination and substitution will be readily
recognized by those of ordinary skill in the art.
[0052] In general, as discussed above, the fundamental and
biomechanical properties of connective tissue, such as scleral
tissue of the eye, may change over time. These fundamental and
biomechanical tissues have properties which include, but are not
limited to, their structure, function, immunology, elasticity,
shock absorption, resilience, mechanical dampening, pliability,
stiffness, rigidity, resilience, configuration, alignment,
deformation, mobility, volume, biochemistry and molecular genetics
of connective tissue proper and newly metabolized connective
tissue. The alterations of these properties may result in an
accumulation of low grade stress/strain of the connective tissue.
This can occur by acute injury or as a normal gradual process of
aging. The alterations of these properties of connective tissue may
change the overall desired properties of the connective tissue and
may also undesirably affect the surrounding tissues, structures,
organs, or systems related to the connective tissue. Examples of
such undesirable affects are increased tension, loss of flexibility
or resilience, along with contracture, fibrosis, or sclerosis, any
of which can prevent the connective tissue or structures that are
related to the connective tissue from performing their desired
function.
[0053] For example, in the human eye, natural alterations in
fundamental and biomechanical properties, specifically resilience,
pliability and elasticity of the scleral tissue of the eye may
affect the ability of the eye to focus. The sclera is the outer
layer of the eye and contains collagen and elastic fiber. It is
commonly referred to as the "white of the eye" and is opaque and
protects the eye. These alterations may affect the ability of the
ciliary muscles and complexes to exert forces on the crystalline
lens to affect central optical power (COP). These alterations of
the scleral tissue may also contribute to an increase in
intraocular pressure and to the loss of the contrast sensitivity of
the eye or visual field of the eye. Biomechanical and structural
alterations of the sclera may affect the refractive ability as well
as the efficiency of the homeostatic functions of the eye such as
intraocular pressure, aqueous production, pH, balance, vascular
dynamics, metabolism and eye organ function. Furthermore,
alterations of the scleral tissue may contribute to damage to the
mechanoreceptors, photoreceptors, or sensory receptors in tissue
layers and structures that are directly or indirectly related to
the scleral tissue. Additionally, fundamental and biomechanical
alterations of the scleral tissue may also be a contributing factor
in the ability of the cerebral cortex to process accurate visual
stimulus necessary for processing visual signals into accurate
visual perception.
[0054] The connective tissue may be any desired connective tissue.
For example, in the eye, the pore matrix may be applied to the
conjunctiva; the cornea (including all its layers and membranes);
the iris; the ciliary body; the ciliary muscles; the anterior
chamber; the zonula ciliaris; the subchoroidal laminathe zonnular
ligaments, the lens capsule, the extraocular muscles and their
associated connective tissues, membranes, and fascia; the posterior
chamber; the lens and all of its associated layers, tissues,
capsules, and membranes; the canal of schlemm, the trabecular
meshwork and all of its associated layers, tissues, capsules, and
membranes; the ora serrata; the vitreous body; the papilla nervi
optici; the optic nerve; the lamina cribrosa; the choroid; the
sclera; the vitreous and associated membranes; the retina; all
epithelial cell layers in the eye; the vascular structures in the
eye; the accessory organs of the eye; and the lymph vessels of the
eye and even the lamina cribrosa bony structure surrounding the
optic nerve head of the eye.
[0055] The present invention described herein relates to the
creation of one or more matrices of pores in the aged connective
tissue so as to restore the lost biomechanical properties of the
connective tissue. Such restorations include but are not limited to
increase in elasticity, resilience, shock absorption, pliability,
structural integrity and/or mobility, optimal organ or system
function. The pores (or perforations) may be formed via laser
ablation or other similar means, and may be maintained in the
connective tissue via the use of a healing inhibitor. Preferably,
the matrices are formed in the scleral tissue of the eye. However,
it will be appreciated that the present invention may be applied to
other connective or non-connective tissue as the case may be where
application of the one or more matrices restores lost biomechanical
properties to the tissue. In at least some embodiments, as will be
explained further herein, the one or more matrices may form a
tessellated pattern of pores in the connective tissue. In at least
one embodiment, the at least one matrices comprises at least one
of: anisotropic patterns, fractal patterns, random nano-patterns,
or any other patterns now known or hereinafter developed that may
alter the properties of the connective tissue to improve the
biomechanics thereof.
[0056] The relationship between the plurality of matrices to one
another in a plurality of planes which creates a change in
biomechanical properties affecting the tissue resilience,
pliability and preferably the vicoelastic properties of the aged
connective tissue and creates "negative stiffness". More physically
explained, the connective tissue biomechanical properties are
changed in a specific and unique manner by the matrices which
create tissue resilience. A second biomechanical effect of the
application of these plurality of matrices is that the tissue
properties has have a specific effect on the Poisson ratio--i.e.
are changed to a value of negative Poisson ratio. The Poisson ratio
(PR) is a fundamental mechanical parameter that approximates the
ratio of relative change in cross sectional area to tensile
elongation. A third biomechanical effect of the application of
these plurality of matrices is that the physical and biomechanical
changes have a remodeling effect on the connective tissue. A fourth
biomechanical effect of the application of the plurality of
matrices is that the physical and biomechanical property changes
have a negative Poisson's ratio structure with mechanical isotropy
in a minimum of two dimensions. When subjected to positive strain
in a longitudinal axis, the transverse strain in the material may
actually be positive (i.e. it would increase the cross sectional
area).
Laser Surgery System
[0057] A surgical laser system 102 for treating connective tissue
according to at least one preferred embodiment will now be
discussed with particular reference to FIGS. 1-15.
[0058] As illustrated for example in FIG. 1, the laser system 102
may be used to remove scleral tissue by ablating the scleral tissue
to form perforations therein. Normal tissue healing may be at least
partially affected to maintain the perforations or pores in the
scleral tissue. In other words, forming the perforations may
inhibit, disrupt, restrict, or otherwise cause the tissue to
deviate from healing, repairing, or regenerating in a manner
conforming to the usual or ordinary course of nature, producing
observable deficiencies therein.
[0059] The surgical laser system 102 includes a laser head 106
coupled to one end of a connector such as a laser delivery fiber
120, the opposite end of which is connected to a delivery apparatus
such as a hand piece 130.
[0060] The laser delivery fiber 120 delivers laser energy from the
laser emitter to the hand piece 130. The laser delivery fiber may
be of any desired construction that transfers laser energy from the
laser to the hand piece 130. In some embodiments the laser delivery
fiber 120 may be a fiber optic assembly. In other embodiments a
collimated arm system or an atomized particle beam may be used in
lieu of delivery fiber 120, as known in the art. The connector may
deliver energy through an optical pumped assembly or a fiber to
fiber assembly.
[0061] Laser 202 may be any desired laser. For example, the laser
may be a gas type laser (e.g argon, krypton, CO2, HeNe, Nitrogen,
etc.), an excimer type laser (e.g. ArF, KF, KCl, etc.), a solid
state type laser (e.g. glass (e.g. fiber optic) crystal (e.g. ruby,
YAG, YLF, GSSG, etc.), dopant (e.g. neodymidium, erbium, holmium
ytterbium, thulium, chromium, etc.)), a diode type laser, a metal
vapor type laser (e.g. Cu, Ag, etc.), or a dye type laser.
Preferred wavelengths may range from 193 nanometers to 10,600
nanometers. The laser may also be a continuous wave, long pulse,
q-switched, or mode locked laser.
[0062] In a preferred embodiment, laser 202 has a wavelength of
about 2.94 .mu.m. In some embodiments a CO2 laser with a 10.6
micron wavelength may be used. In some embodiments a Ho:YAG laser
with a 2.1 micron wavelength may be used.
[0063] In at least one embodiment, the pulse width of laser 202 may
be approximately 250 .mu.s. In some embodiments "Long Pulse" lasers
are used with pulse widths in the hundreds of microseconds range.
In some embodiments Q-switched lasers with pulse widths in the ten
to one hundred nanosecond range are used. In some embodiments
Mode-locked lasers with pulse widths in the tens to hundreds of
picoseconds are used. In some embodiments ultrafast lasers with
pulse widths in the tens to hundreds of femtoseconds are used. In
at least one embodiment, the repetition rate may range from 3 to 50
pps, preferably selected from 3, 10, 15, 20, 25, 30, 40 and 50 pps.
In some embodiments, the repetition rate may range from hundreds of
hertz to tens of kilohertz. Exemplary lasers are described in the
materials appended hereto and are hereby incorporated by reference
in their entirety.
[0064] Spatial mode structure in embodiments of the invention
herein may be varied. In some embodiments single mode Gaussian
spatial mode may be used. In other embodiments multi-spatial mode
lasers may be used.
[0065] Energy distribution from lasers according to embodiments of
the invention may in some embodiments be Gaussian and in some
embodiments flat-top.
[0066] As shown for example in FIG. 2, the delivery system may be
configured to direct the laser energy along a path from a beam
input location 204 to a beam output location 216. This may be
accomplished, inter alia, via a series of mirrors and/or lenses
204, 208, 210, 212, 214, 216 configured to direct the laser energy.
The series of mirrors and/or lenses may be adjustable either
manually, or automatically so as to direct the laser energy to one
or more desired locations.
[0067] The delivery system may further be configured to focus the
laser energy onto the scleral tissue 140. This may be accomplished,
inter alia, via a series of mirrors and/or lenses 204, 208, 210,
212, 214, 216 configured to focus the laser energy. The series of
mirrors and/or lenses 204, 208, 210, 212, 214, 216 may be
adjustable either manually, or automatically so as to focus the
laser energy to one or more desired locations.
[0068] The delivery system may also include an image platform, a
viewing platform, a slit lamp, a microscope, or a viewscope
150.
[0069] The delivery system 200 may further be configured to cause
the laser energy to form the pore matrix in the scleral tissue.
[0070] In at least one embodiment, the delivery system comprises a
hand piece 130 configured to apply the laser energy in the pore
matrix over the tissue. Such application may be manually or
automatic. For example, hand piece 130 may be configured to be
moved in a pore matrix over the tissue manually via a trained
physician or operator 160.
[0071] In some embodiments, the delivery system comprises a
scanning mechanism or system (such as eye tracker 304 in FIG. 4)
configured to move the laser energy in the pore matrix over the
tissue. This may be an automated process. For example, in at least
one embodiment, the delivery system comprises a 2D or 3D
galvano-scanning system configured to move the laser energy in a
desired pattern over the tissue. The scanning system may also
include a reverse imagery device and software platform. As
discussed further herein, the scanning mechanism or system directs
the laser ablation beam from pore to pore during formation of the
pore matrix. Conversely, as also discussed herein, the tracking
mechanism maintains the relative positioning of the scanning system
and the target tissue stable. The tracking system is
communicatively coupled to the scanning system for at least that
reason.
[0072] In at least one embodiment, the delivery system comprises a
mask configured to apply the laser energy in the pore matrix over
the tissue. For example, the mask may selectively permit laser
energy to reach the scleral tissue.
[0073] In some embodiments a mask or film may incorporate a
biological, chemical, electrical, ion, or other sensor in order to
control numerous parameters of laser beam function and
homogenization. In some embodiments a sensor can be incorporated
into a mask, film or galvo-optic assembly to control the gain
medium and bandwidth function of the laser beam. In other words, in
some embodiments, the scanning system includes a biofeedback
control loop. The biofeedback loop provides real-time feedback
about the characteristics of the irradiated tissue, such as
thickness, topography, focus, hydration, etc. In at least one
embodiment, the laser beam used to irradiate the tissue is measured
to give this feedback and is adjusted based on the real-time tissue
characteristics.
[0074] In at least one embodiment, the laser and delivery system is
an Ytterbium Fiber to Fiber system (such as in FIG. 1, element 120)
that does not require a crystal. In at least one embodiment, laser
202 has an amplifier that is either in the body piece, the head
piece, or remote hand piece 130.
[0075] It is important to note, that none of the aforementioned
features or embodiments are intended as being mutually exclusive
and all combinations thereof are specifically contemplated. For
example, the delivery system may comprise hand piece 130 having a
scanning mechanism therein to be used in conjunction with a
mask.
[0076] Turning to FIG. 1, a medical treatment system 100 using a
laser system 102 is shown that may be used in performing the
methods later described in accordance with the present
invention.
[0077] In the example embodiment, medical treatment system 100
broadly requires the use of laser system 102 which delivers a laser
beam via laser delivery fiber 120 to hand piece 130 and then to
patient (also referred to herein as patient's eye) 140. Operator
160 controls laser system 102 via foot pedal 114 and laser beam via
hand piece 130 and monitors progress of a medical procedure via
surgical microscope 150.
[0078] In the example embodiment laser system 102 is comprised of
various components including system control electronics 104, laser
head 106, laser cooling system 108, HV power supply 110, and system
power supplies 112.
[0079] In some embodiments laser cooling system 108 is a water
cooling system. In some embodiments laser cooling system 108 may be
an air or chemical substrate. Also included may be a user interface
button and LED panel including status indicators such as on, off,
standby, or others. An interface exists between laser system 102
and delivery fiber 120.
[0080] In the example embodiment laser system 102 creates a laser
beam that has an operational wavelength of 2.94 microns and typical
pulse repetition frequency of 10-50 Hz. The laser pulsewidth is
typically 250 microseconds.
[0081] Laser system 102 is coupled to hand piece 130 held by
operator 160 via a fiber optic cable. To transmit mid-infrared
light, the fiber material is a chalcogenide glass. It could be made
from germanium or ZBLAN. Alternatively, the fiber could be a hollow
core fiber, a photonic crystal fiber, or a double- or multi-clad
fiber. Fiber core diameter is about 400 microns, but could range
from single mode to 600 microns diameter.
[0082] Hand piece 130 interfaces at the proximal end to the fiber
cable and couples the light via focusing optics to a waveguide tip.
This tip can be composed of amorphous glass or crystalline
material, such as quartz or sapphire. The diameter of the tip may
range from 100 to 600 microns and may be straight or bent at an
angle. The end of the tip may be polished or cleaved flat or may be
angled or rounded. The tip of hand piece 130 is positioned in close
proximity to the tissue to be treated.
[0083] Hand piece 130 may be passive or active. An active hand
piece 130 may communicate in some way with laser control system 102
to activate/deactivate the laser beam, or to change other laser
parameters (e.g. pulsewidth, repetition frequency, or pulse
energy).
[0084] An alternative configuration for hand piece 130 is to
contain the actual laser crystal and cavity. Semiconductor diodes
are used rather than flashlamps to pump the laser crystal and the
diode optical energy is delivered to the laser crystal in handpiece
130 via fiber optics as disclosed in associated reference patent
Shen, U.S. Pat. No. 6,458,120, the entire contents and disclosure
of which is herein incorporated by reference.
[0085] In some embodiments a hands-free system may be used in place
of hand piece 130. In some embodiments a slit lamp interface may be
used to monitor or perform procedures. In some embodiments a supine
interface may be used as is common in some laser eye surgery
procedures.
[0086] In the example embodiment surgical microscope 150 is used to
provide magnification of the treatment area for operator 160 to
guide treatment. In other embodiments surgical microscope 150 may
be another viewing apparatus that provides magnification or other
vision of the treatment area.
[0087] Physician or operator 160 may interface with the system in
numerous manners in the various embodiments of the invention. Some
embodiments include a touchscreen video monitor. Other embodiments
include a video monitor without touchscreen capabilities. Some
embodiments allow for the use of a keyboard and mouse, hand
activated switch, additional foot pedals, virtual reality or
three-dimensional goggles, remote interaction capabilities, stereo
surgical microscopes, or other related equipment.
[0088] In some embodiments a laser crystal is disposed between two
reflective surfaces and these help form a laser beam. In some
embodiments the laser crystal is a rod crystal or a thin disk
crystal. An aperture member may be positioned between the laser
crystal and one of the reflective surfaces may include a
substantially circular aperture for passing the laser beam. In many
embodiments the size of the aperture is selectively adjustable. The
aperture member may have a plurality of apertures of various
different sizes and is rotatable about an axis of rotation. The
axis of rotation may be parallel to the longitudinal axis of the
laser crystal. By appropriately rotating the aperture member, a
selected one of the apertures may be positioned to pass the laser
beam. In some embodiments, an aperture is used to adjust the laser
beam size. The aperture is located outside the laser cavity. The
aperture is located relatively close to irradiation surface. In
such embodiments, the laser is preferably a handheld probe diode
laser pump crystal.
[0089] In some embodiments a stepper motor and flexible shaft are
utilized for rotating the aperture member. At least one of the
apertures may be surrounded by a beveled portion of the rotatable
member.
[0090] In some embodiments, two lasers with different size fixed
apertures may be utilized and directed to a common surface.
According to an aspect of the invention, an articulated arm is
provided in some embodiments along with one or more refocussing
optics for refocussing the laser beam as it travels through the
arm.
[0091] In some embodiments, the laser source is provided along with
a galvanometer for directing each of two laser beams to a surface
to be treated. Such an arrangement may provide additional
versatility and control.
[0092] In some embodiments, the laser source is provided along a
fiberoptic along with a hand piece and one or more focusing optics
or tips. According to another aspect, a fourth laser source is
provided with a semiconductor disk.
[0093] For broad wavelength tuning and for ultrashort pulse
generation, other ytterbium-doped gain media may offer a wider gain
bandwidth. Examples are tungstate crystals (Yb:KGW, Yb:KYW,
Yb:KLuW), Yb:LaSc3(BO3)4 (Yb:LSB), Yb:CaGdAlO4 (Yb:CALGO) and
Yb:YVO4. Particularly promising are novel sesquioxide materials
such as Yb:Sc2O3, Yb:Lu2O3 and Yb:Y2O3, having excellent
thermo-mechanical properties and a potential for very high output
powers and high efficiencies. A slope efficiency of 80% has been
demonstrated with Yb:Lu2O3.
[0094] Nd:YAG or Nd:YVO4 may also be used in thin-disk lasers, e.g.
when a wavelength of 1064 nm is required, or when the much smaller
saturation energy of Nd:YVO4 is relevant. Generally, a high doping
concentration is desirable for thin-disk gain media. This allows
one to use a rather thin disk (and thus to minimize thermal
effects) without arranging for too many passes of the pump
radiation. Most ytterbium doped gain media are quite favorable in
this respect.
[0095] According to another aspect a fifth laser source is provided
with an apparatus wherein said apparatus is part of a stand-alone
semiconductor wafer edge-processing system or is a fiber-optic
assembly is integrated into a module for use in a semiconductor
wafer edge-processing system. A unique light amplifier platform to
be adapted for laser marking and engraving is found in Ytterbium
fiber amplifiers.
[0096] In some embodiments the fiber to fiber laser system (such as
shown in FIG. 1) comprising of a clad fiber pumping technique
creates coherence in the beam structure that closely approaches a
Gaussian beam intensity profile. A method of ablating biological
tissue with a laser system comprising of a Ytterbium fiber-to-fiber
solid state laser wherein the optical fiber itself is the lasing
medium and which contains no laser crystal or intra-cavity optics
near the galvo assembly and the entire beam steering/galvo mount
assembly is reduced to a compact module.
[0097] In some embodiments the assembly is a true solid-state
design and comprises of a pumping chamber optics which is grown
into the active fiber assembly including a built-in ability of the
system to automatically monitor the output power of the laser
source through a self-calibrating feature which constantly provides
minute feedback, keeping the output power constant regardless of
variations in incoming voltage or any possible slight degradation
of the individual diodes.
[0098] In some embodiments, the small package size of the
fiber-to-fiber laser allows positioning of the beam in almost any
angle, giving an almost unlimited angle spatial treatment area.
[0099] In some embodiments, the preferred wavelength of the
near-infrared frequency of Ytterbium fiber at 1060 nm which can be
doubled, tripled or quadrupled. Preferably in this invention the
2940 nm wavelength parameter is presented.
[0100] In some embodiments, the laser system comprises a built-in
power monitoring feedback circuits as is known in the art.
[0101] In some embodiments the basic laser system is an all fiber
format that allows adjustment of pulse energy and/or change pulse
repetition rate without affecting any of the output beam
parameters.
[0102] In some embodiments the basic laser system features a single
mode M-squared of <1.2. M-squared is a beam quality metric
indicating how close the laser beam is to a true Gaussian beam.
[0103] Provided herein is a method of ablating biological tissue in
which the laser source is a single-frequency, broadly-tunable
mid-IR laser.
[0104] In some embodiments the laser beam may be positioned with
sub-nanometer accuracy. This may be accomplished with an automated,
high resolution, resonant probe AFM instrument that can be
connected to a closed loop nano-positioning system. In some
embodiments three axis nano-positioning systems with 100, 200, and
300 micron ranges of motion are provided in all three axes.
[0105] Other components may be provided in some embodiments
including laser components such as a sensor preamplifier, an
Akiyama probe, a mounting board, and/or a closed loop nano servo
controller.
[0106] Turning to FIG. 2, an embodiment of a medical treatment
system is shown using a laser treatment system 200 according to an
embodiment of the present invention.
[0107] In the example embodiment, a hands-free laser treatment
system 200 consists of a treatment laser 202 emitting a laser beam
which travels through relay lens 204 to dichroic or flip-in 208.
Treatment laser 202 is coupled to the system either via a fiber
optic, a hollow waveguide, or free space propagation. For free
space propagation, the laser beam may be manipulated with fixed
mirrors or prisms, or mirrors or prisms on an articulating arm. One
or more lenses are used to collimate and/or change the size of
and/or image the laser beam. Additional transport optics may be
used to control the beam as it is brought to the focusing
optics.
[0108] In some embodiments active steering elements change the
angle of the beam into the focusing subsystem to scan the focus
spot over an area of tissue. These active elements can be galvo,
voice coil, DC motor, stepper motor, piezo-driven or MEMS mirrors.
Alternatively, the steering elements could be refractive or
diffractive elements, such as Risley prisms or an electro-,
magneto-, or acousto-optic modulators. These are alternatively
referred to herein as a scanning system.
[0109] In the example embodiment, the beam or beams leave dichroic
or flip-in 208 and travels to Galvo1 210. Galvo1 210 may consist of
a mirror which rotates through a galvanometer set-up in order to
move a laser beam. The beam or beams leave Galvo1 210 and travel to
Galvo2 212 which may be a similar setup to Galvo1 210. The beam or
beams leave Galvo2 212 and travel to dichroic (visible/IR) 214.
Operator 160 may monitor the beam or beams at dichroic (visible/IR)
214 by using a surgical microscope 150. The beam or beams travel
from dichroic (visible/IR) 214 through focusing optics 216 to
patient eye 140.
[0110] In some embodiments the tracking system further includes a
3D image stabilization system for microscopy is provided, capable
of controlling temperature gradients, sample drift, and microscope
drift.
[0111] In some embodiments focusing optics 216 may include a
focusing subsystem focuses the beam onto the tissue to be treated,
creating a focus spot with desired spot size, energy profile, and
focus depth. The focusing subsystem can consist of refractive,
reflective, or diffractive elements.
[0112] In some embodiments visual spotting laser 206 may be a low
power laser employed as a spotting beam to aid visualization of the
focus spot location on tissue. Visual spotting laser 206 may be a
gas, solid state or semiconductor laser. The preferred embodiment
would be a visible wavelength laser that can be seen with the naked
eye or with a silicon CCD or CMOS camera.
[0113] Visual spotting laser 206 is injected into the optical
system via a beam-splitter dichroic or flip in 208 optic and is
preferably collinear to the line of sight of treatment laser 202.
Alternatively, an element that selectively blocks some of the
treatment or spotting laser beam and allows a portion of the other
beam to pass could be used so that the spotting and treatment beams
are incident on the tissue simultaneously. Alternatively, a
rotating or oscillating reflective element that alternates between
the treatment and spotting lasers could be used. In other
embodiments the beams may reach dichroic or flip-in 208 at
staggered times.
[0114] It is also possible to have the visible spotting beam
integral to the treatment laser. An example would be to propagate a
visible laser beam through the intra-cavity mirrors or a solid
state laser. The intra-cavity mirrors could be coated to transmit
the spotting laser wavelength while reflecting the treatment laser
wavelength.
[0115] Alternatively, multiple spotting laser beams may be used and
aligned such that they are coincident at the focal plane of the
focusing optics. If the tissue is not in the focus plane, multiple
visible beams will be apparent, indicating the need to adjust
focus.
[0116] A line of sight for operator 160 to view the area of tissue
being treatment is injected after the steering elements and before
the focusing subsystem. A beam-splitter dichroic 208 is used so
that the tissue may be viewed concurrently with the spotting and/or
treatment lasers 206. It is also possible to employ a reflective
element to combine the treatment/spotting laser lines of sight with
the visible line of sight. This reflective element may create a
central obscuration in the laser beam or visible line of sight.
Shown in the figure is a surgical, binocular microscope head 150.
Instead of a direct visual system to the operator's eye, a CCD or
CMOS camera with imaging optics could be employed. This preferably
includes a controller for adjusting for parallax error.
[0117] Alternatively, the line of sight could be located after
focusing optics 216. A similar aperture sharing element as
described above could be used to combine the lines of sight. In
this case, separate focusing optics 216 would be required for
operator 160 to focus on the surface of the tissue such as
patient's eye 140.
[0118] Turning to FIG. 3, a laser treatment system 300 according to
an embodiment of the present invention is shown. FIG. 3 shows the
optical system of FIG. 2, with additional subsystems added for
monitoring and controlling the depth of tissue ablation and for
tracking eye movement.
[0119] Similar to the embodiment depicted in FIG. 2, in the example
embodiment, laser treatment system 300 consists of a treatment
laser 202 emitting a laser beam which travels through relay lens
204 to dichroic or flip-in 208. Visible spotting laser 206 emits a
laser beam which also travels to dichroic or flip-in 208. In some
embodiments the beams from treatment laser 202 and visible spotting
laser 206 may meet simultaneously at dichroic or flip-in 208. In
other embodiments the beams may reach dichroic or flip-in 208 at
staggered times.
[0120] The beam or beams leave dichroic or flip-in 208 and travels
to Galvo1 210. Galvo1 210 may consist of a mirror which rotates
through a galvanometer set-up in order to move a laser beam. The
beam or beams leave Galvo1 210 and travel to Galvo2 212 which may
be a similar setup to Galvo1 210. The beam or beams leave Galvo2
212 and travel to dichroic (visible/IR) 214. Operator 160 may
monitor the beam or beams at dichroic (visible/IR) 214 by using a
surgical microscope 150. The beam or beams travel from dichroic
(visible/IR) 214 through focusing optics 216 to patient eye
140.
[0121] In FIG. 3, additional monitoring elements are provided for
use by operator 160 to aid in medical procedures. Depth control
subsystem 302 is coupled to surgical microscope to assist in
controlling the depth of ablation procedures in accordance with the
present invention. Similarly, eye tracker 304 is coupled to
surgical microscope to assist in tracking landmarks on patient eye
140 during medical procedures in accordance with the present
invention.
[0122] Depth control may be achieved by viewing the ablation region
and visually detecting a change in structure or color in the image.
A CCD camera and passive or active illumination may be employed to
visualize the ablation region of patient's eye 140. Image data may
be processed and algorithms used to segment the image to determine
characteristics of the image within a region of interest. These
characteristics may be compared to known, stored, or computed
values that may be used to determine when to stop the treatment
laser exposure. Alternatively, a measure of ablation depth may be
made and compared to known or stored maximum depth desired for
ablation. Alternatively, the subsurface tissue may be imaged using,
for example, ultrasound or optical coherence tomography. The depth
of ablation may be viewed in reference to imaged landmarks or
layers to provide indicators when desired ablation depth has been
achieved.
[0123] The region of tissue to be treated must remain positionally
stable during treatment. In the case of the eye, whole body or head
movement, as well as ocular movements such as saccades, smooth
motion pursuit, vergence, and vestibular-ocular movements must be
detected and compensated. One method of accomplishing this is via
imaging of the eye with a camera, such as a CCD or CMOS camera.
Image data can be processed in a variety of ways. One method is to
extract features in the image field and track changes in position
relative to the fixed position of the camera pixels. A feedback
loop to the steering elements is employed to compensate the line of
sight of the treatment beam to maintain its relative position on
the eye. The imaging camera may be in front of or behind the
steering elements. If it is in front, then the compensation will
run open-loop, in that there is no error signal between the
commanded and resultant position of compensation. If the camera is
behind the steering elements, then the image field of the camera
can generate a continuous error signal to feedback to the steering
elements. If the system has one set of steering elements, then they
will be used both for scanning the treatment laser beam over tissue
and compensating for eye motion. Alternatively, two sets of
steering elements could be employed to separate these
functions.
[0124] Turning to FIG. 3A, a laser treatment system 301 according
to an embodiment of the present invention is shown.
[0125] In this embodiment, a treatment laser beam travels to
dichroic 208. At dichroic 208 the laser beam travels to Galvo Setup
320 which consists of Galvo1 210 and Galvo2 212. The beam then
passes from Galvo Setup 320 to focusing optics 216 and ultimately
to patient eye 140.
[0126] Also provided for in this embodiment is a control and
monitoring system which broadly consists of a computer 310, video
monitor 312, and camera 308. Camera 308 provides monitoring of the
laser beam at dichroic 208 via lens 306. Camera 308 transmits its
feed to computer 310. Computer 310 is also operable monitor and
control Galvo Setup 320. Computer 310 is also coupled to video
monitor 312 to provide a user or operator a live feed from camera
308.
[0127] In some embodiments of the invention a dual axis closed loop
galvanometer optics assembly is used.
[0128] Since multiple lasers systems may be used for treatment in
some embodiments, additional laser systems will now be
described.
[0129] The laser system may include a cage mount galvanometer
containing a servo controller, intelligent sensor, feedback system
and mount assembly with an optical camera. Some embodiments may
include use of a cage mount galvanometer optics assembly. Some
embodiments may include ultra-high resolution nano-positioners to
achieve sub-nanometer resolution.
[0130] To expand, FIG. 3A shows more detail of a CCD (or CMOS)
camera-based eye tracker subsystem. Dichroic 208 beamsplitter is
used to pick off visible light, while allowing the IR treatment
beam to transmit. The beamsplitter 208 is located in front of the
steering elements, shown here as galvo mirrors 320. Lens 306 images
the tissue plane (eye) onto the camera. Features in the image field
(e.g. blood vessels, edge of the iris, etc.) are identified by
image processing and their coordinates in the camera pixel field
computed. If the eye moves within the pixel field frame-to-frame,
the change in position of the reference features can be computed.
An error function is computed from the change in reference feature
position and commands issued to the galvo mirrors 320 to minimize
the error function. In this configuration, the optical line of
sight is always centered on the treatment spot, which is at a fixed
coordinate in the camera pixel field. The apparent motion from
repositioning the galvos 320 will be to move the eye image relative
to the fixed treatment spot.
[0131] Turning to FIG. 3B, another embodiment of a laser treatment
system 303 according to an embodiment of the present invention is
shown. FIG. 3B is similar to FIG. 3A, except that the eye tracking
subsystem is located after galvo mirrors 320.
[0132] In this embodiment, a treatment laser beam travels to Galvo
Setup 320 which consists of Galvo1 210 and Galvo2 212. The beam
then passes from Galvo Setup 320 to dichroic 208. At dichroic 208
the laser beam travels to focusing optics 216 and ultimately to
patient eye 140.
[0133] Also provided for in this embodiment is a control and
monitoring system which broadly consists of a computer 310, video
monitor 312, and camera 308. Camera 308 provides monitoring of the
laser beam at dichroic 208 via lens 306. Camera 308 transmits its
feed to computer 310. Computer 310 is also operable monitor and
control Galvo Setup 320. Computer 310 is also coupled to video
monitor 312 to provide a user or operator a live feed from camera
308.
[0134] Here, the eye image is shown centered in the pixel field.
When eye motion is detected within the pixel field, the galvos 320
are repositioned to move the treatment spot to a new position
within the pixel field corresponding to the movement of the eye,
and to a desired fixed position relative to the eye reference
features.
[0135] With reference to the aforementioned biofeedback look, eye
tracking includes in some embodiments includes use of light source
producing an infrared illumination beam projected onto an
artificial reference affixed to an eye. The infrared illumination
beam is projected near the visual axis of the eye and has a spot
size on the eye greater than the reference and covering an area
when the reference moves with the eye.
[0136] In some embodiments the reference has a retro-reflective
surface that produces backward scattering orders of magnitude
stronger than backward scattering from the eye would. An optical
collector may be configured and positioned a distance from the eye
to collect this backward scattered infrared light in order to form
a bright image spot of the reference at a selected image
location.
[0137] The bright image spot appears over a dark background with a
single element positioning detector positioned at the selected
image location to receive the bright image spot and configured to
measure a two-dimensional position of the bright image spot of the
reference on the positioning detector. An electric circuit may be
coupled to the positioning detector to produce positioning signals
indicative of a position of the reference according to a centroid
of the bright image spot based on the measured two-dimensional
position of the bright image spot on the positioning detector.
[0138] FIG. 3C illustrates a camera correction system according to
an embodiment of the present invention.
[0139] In the example embodiment the top row illustrates the camera
focus location after galvos have been used and the bottom row
illustrates the camera focus location before galvos. Various
landmarks 392 may be seen in the example embodiments including
capillaries, iris, pupil, etc. Treatment spot 394 may also be seen
in each embodiment.
[0140] As is shown in the example embodiment the top row of focus
before the galvos each show the pupil of as the center pixel of
each image. Compensation after galvos in the bottom row allows the
treatment spot 394 to remain the focus of the camera's attention in
each image and thereby allow the system to remain in position for
the associated procedure.
[0141] Turning to FIG. 3D, a camera-based eye tracker flow diagram
330 is depicted showing a process according to an embodiment of the
present invention.
[0142] Broadly put, the diagram represents the use of a CCD or CMOS
camera to capture an image of eye. Image data is transmitted to a
computer, where key features are segmented/extracted (e.g. blood
vessels, iris features, edge of pupil). The image is stored as a
reference frame. Subsequent images are then compared to reference
frame. A shift is computed after comparing reference features in
pixel coordinates. Conversion of pixel coordinates to scanning
system coordinates then occurs before commanding the scanning
system to deviate treatment beam line of site to restore
relationship relative to reference features. If the shift is too
large or out of range of scanning system, halt procedure and take
steps to reacquire the target image field.
[0143] As a more detailed explanation referencing each step, an
initialization or starting sequence according to some embodiments
requires capture image frame in step 332 before processing the
captured image frame in order to extract features in step 334. This
captured frame with extracted features is then used to set a
reference frame in step 336.
[0144] After a reference frame is set, step 338 consists of
capturing an additional image frame, called a current frame. This
image or current frame is processed in step 340 in order to extract
features. Step 342 consists of comparing the current frame to the
reference frame which was set in step 336. An image shift is
computed between the current frame and the reference frame in order
to determine the difference between the frames. A comparison to a
pre-set threshold allows the system to determine if the image shift
exceeds the pre-set threshold and stops the procedure at this point
by going to step 352.
[0145] If an image shift does not exceed the pre-set threshold and
therefore is not too large, the system computes a compensation
level in step 346 in order to compensate for the change or shift
between the current frame and the reference frame. This
compensation level is computed into physical coordinates used by a
scanner in step 348. The scanner is then commanded to compensate
using the coordinates in step 350. After this compensation step 338
occurs and another current image frame is captured and the cycle
continues.
[0146] Turning to FIG. 3E, a flow diagram for a laser ablation
procedure 360 embodiment is shown in accordance with the present
invention.
[0147] Generally put, the procedure flow represents a procedure for
stepping through, one quadrant at a time, one pore at a time, an
ablation pattern. The procedure starts with a patient focused on an
off-axis fixation target. A position scanning system locates pore 1
coordinates. Eye tracking is initiated, starting with reference
frame. Pore 1 is ablated while tracking. The procedure is halted if
eye movement is out of range to prevent harm or other negative
consequences. Upon completion of pore 1, the position scanning
system locates pore 2 coordinates and repeats the eye tracking and
ablation process. These steps are repeated until quadrant 1 pattern
complete. The fixation target is then moved and patient focuses on
new position and repeat application of ablation pattern on a new
quadrant.
[0148] As a more detailed explanation referencing each step, in the
example embodiment a patient is positioned in step 362 in order to
receive the treatment. The patient is then instructed to fixate
their gaze for a first quadrant procedure in step 364.
[0149] The line of sight of the laser beam is positioned to a first
pore position in step 366 before a tracker reference is set for the
first pore position in step 368. The user or operator then
initiates the ablation in step 370 and the first pore is
ablated.
[0150] The user or operator then moves to step 372 and positions
the line of sight of the laser beam for the second pore position
before tracker reference is set for the second pore position in
step 374. The user or operator then initiates the ablation in step
376 and the second pore is ablated.
[0151] The several steps described in the above paragraph which are
similar to those in the paragraph above it are repeated in step 378
until ablation in the quadrant is complete.
[0152] After the quadrant is complete, the patient is instructed to
fixate their gaze for a second quadrant in step 380 and the process
repeats for each successive quadrant until the procedure as a whole
is complete.
[0153] Also provided for in the diagram is eye tracking 382 that
represents the steps required and repeated in tracking the position
of the eye concurrently with the steps of laser ablation procedure
flow 360 in the embodiment.
[0154] Also provided for in the diagram is eye tracking 384 that
represents the steps required and repeated in tracking the position
of the eye concurrently with the steps of laser ablation procedure
flow 360 in the embodiment.
[0155] In some embodiments an eye tracking subsystem may be a
camera based imaging system. This camera based imaging system may
be used for image feature identification and to assist in tracking
position of a laser beam during a procedure. Feedback from the eye
tracking subsystem is provided to the scanning system to maintain
correct position during procedures.
[0156] In some embodiments the eye tracking subsystem is used for
registration of previously created pores (also referred to as
voids) for retreatment or additional treatment as necessary.
[0157] Also provided for in the diagram is depth control 386 that
represents the steps required and repeated in controlling the depth
of the laser beam on the eye concurrently with the steps of laser
ablation procedure flow 360 in the embodiment.
[0158] Depth control subsystem in some embodiments includes an
imaging system and/or Optical Coherence Tomography. The imaging
system may include detection of a pigmented layer or layers in
order to ensure proper depth is reached without exceeding a
particular limit.
[0159] FIG. 4 illustrates a laser treatment system 400 according to
an embodiment of the present invention. In the example embodiment,
laser treatment system 400 consists of a treatment laser 202
emitting a laser beam which travels through relay lens 204 to
dichroic or flip-in 208. Visible spotting laser 206 emits a laser
beam which also travels to dichroic or flip-in 208. In some
embodiments the beams from treatment laser 202 and visible spotting
laser 206 may meet simultaneously at first dichroic or flip-in 208.
In other embodiments the beams may reach first dichroic or flip-in
208 at staggered times.
[0160] The beam or beams leave first dichroic or flip-in 208 and
travels to a second dichroic 208. The beam or beams leave second
dichroic 208 and travel to Galvo1 210. Galvo1 210 may consist of a
mirror which rotates through a galvanometer set-up in order to move
a laser beam. The beam or beams leave Galvo1 210 and travel to
Galvo2 212 which may be a similar setup to Galvo1 210. The beam or
beams leave Galvo2 212 and travel to dichroic (visible/IR) 214.
Operator 160 may monitor the beam or beams at dichroic (visible/IR)
214 by using a surgical microscope 150. The beam or beams travel
from dichroic (visible/IR) 214 through focusing optics 216 to
patient eye 140.
[0161] In FIG. 4, additional monitoring elements are provided for
use by operator 160 to aid in medical procedures. Depth control
subsystem 302 assists in controlling the depth of ablation
procedures in accordance with the present invention and receives
input from second dichroic 208. Similarly, eye tracker 304 assists
in tracking landmarks on patient eye 140 during medical procedures
in accordance with the present invention and also receives input
from second dichroic 208. Another dichroic 208 is shown in the
example embodiment splitting the beam with outputs to eye tracker
304 and depth control subsystem 302.
[0162] FIG. 4A illustrates a laser treatment system including
ablation pore depth according to an embodiment of the present
invention.
[0163] FIG. 4A generally shows a treatment laser beam traveling to
dichroic 208 before travelling to Galvo1 210, then to Galvo2 212,
through focusing optics 216, and to patient eye 140.
[0164] An OCT system 404 is an Optical Coherence Tomography system
used to obtain subsurface images of the eye. As such, when coupled
to computer 310 which is coupled to video monitor 312, OCT system
404 provides a user or operator the ability to see subsurface
images of the tissue ablation.
[0165] In at least some embodiments OCT provides a real-time,
intraoperative view of depth levels in the tissue. OCT may provide
for image segmentation in order to identify sclera interior
boundary to help better control depth.
[0166] OCT system 404 uses an OCT measurement beam, injected into
the treatment beam line of sight via a dichroic beam splitter 208,
located before the scanning system. In this way, the OCT system
line of sight is always centered on the pore being ablated. The OCT
system is connected to a computer 310 for processing the images and
for control of the laser.
[0167] In some embodiments of the invention an anatomy avoidance
subsystem is provided to identify critical biological obstacles or
locations during procedures (e.g. blood vessels and others). As
such, subsurface visualization may be provided to identify
obstacles such as blood vessels intra-operatively.
[0168] Also shown in FIG. 4A is a simple diagram of an ablation
pore in the sclera showing an example of the depth of an ablation
in relation to the inner boundary of the sclera.
[0169] Turning to FIG. 4B, a flow diagram of OCT-based depth
control 410 is shown according to an embodiment of the present
invention.
[0170] In general, The OCT system executes a repetitive B-scan,
synchronized with the laser. The B-scan shows the top surface of
the conjunctiva and/or sclera, the boundaries of the pore being
ablated, and the bottom interface between the sclera and the
choroid or ciliary body. Automatic image segmentation algorithms
are employed to identify the top and bottom surfaces of the sclera
(typically 400-1000 microns thick) and the boundaries of the
ablated pore. The distance from the top surface of the sclera to
the bottom surface of the pore is automatically computed and
compared to the local thickness of the sclera. In some embodiments
this occurs in real time. When the pore depth reaches a predefined
number or fraction of sclera thickness, ablation is halted and the
scanning system indexed to the next target ablation location. In
some embodiments images may be segmented to identify interior
sclera boundaries.
[0171] With reference to the steps in the figure, in the example
embodiment a starting or initialization set of steps occurs first.
This starting set of steps begins with positioning to a pore
coordinate in step 412. A B-scan of the target region occurs in
step 414. This scan creates an image which is processed in step 416
in order to segment and identify the sclera boundary. A distance is
then computed in step 418 between the conjunctive surface and the
sclera boundary.
[0172] After completion of this starting set of steps ablation is
initiated in step 420. A laser beam pulse is fired in step 422
followed by a B-scan in step 424. This B-scan creates an image that
is then segmented in step 426 and pore depth and ablation rate are
computed from the image. This pore depth and ablation rate are
compared to the target depth in step 430. If the target depth has
not been reached then the process loops back to step 422 and
repeats. Upon reaching a target depth step 432 stops the ablation
process and the starting process begins again at step 434 with
positioning to a next pore coordinates.
[0173] FIG. 5A-FIG. 5C show various means of coupling the treatment
laser into the optical system.
[0174] Turning to FIG. 5A, a laser treatment system lens placement
is shown according to an embodiment of the present invention. In
the example embodiment the laser beam emitted from treatment laser
202 travels through a waveguide, either hollow or fiber. These were
described above in depth in FIG. 1.
[0175] Turning to FIG. 5B, a laser treatment system lens placement
is shown according to an embodiment of the present invention. In
the example embodiment free space propagation is shown. A
multi-lens collimating telescope can serve to change the size of
the beam (expand or reduce) as well as image the beam waist or
output aperture of the laser beam to some location in the optical
system. Shown here is a so-called Keplarian configuration, where a
real focus is formed inside the telescope.
[0176] Turning to FIG. 5C, a laser treatment system lens placement
is shown according to an embodiment of the present invention. In
the example embodiment, an aperture is used similar to the
embodiment in FIG. 5B except that this embodiment uses a Galilean
configuration telescope with a negative and a positive element
rather than a Keplarian configuration. This configuration does not
form a real image within the telescope. This optical configuration
is also known as a telephoto or reverse telephoto configuration
(depending on orientation), which can be important when considering
the desired position of the beam waist or laser beam output
aperture in the system.
[0177] FIG. 6 illustrates a laser treatment system component map
600 showing relation of related subsystems according to an
embodiment of the present invention.
[0178] In general laser treatment system component map 600 shows a
laser 602, a laser delivery fiber 120, laser control system 604,
monitoring system 608, and beam control system 606.
[0179] Laser 602 is generally made up of several subsystems. In the
example embodiment these subsystems include system control
electronics 104, Er:YAG laser head 612, laser cooling system 108,
HV power supply 110, and system power supplies 112. Foot pedal 114
provides some control for the system user. Laser 602 transmits a
laser beam via laser delivery fiber 120 to beam control system
606.
[0180] Beam control system 606 is generally made up of beam
transport optics 624, red spotting laser 626, galvo mirrors 628,
beam delivery optics 630, and active focus 632.
[0181] Laser control system 604 maintains a link to laser 602 via a
laser sync and to beam control system 606 via power control
position status. Laser control system 604 is generally made up of a
user interface 614, power supply 616, galvo controller 618, galvo
controller 620, and microcontroller 622. Laser control system 604
is also manipulable via joystick 610.
[0182] Monitoring system 608 is generally made up of CCD camera 634
and visual microscope 636.
[0183] In some embodiments a fiber laser is used which is composed
of an undoped cladding and a doped core of higher refraction. The
laser beam travels through the fiber guided within the fiber core
and experiences a high amplification due to the length of
interaction. Fiber lasers are considered advantageous to other
laser systems because, among other qualities, they have simple
thermal management properties, high beam quality, high electrical
efficiency, high optical efficiency, high peak energy, in addition
to being low cost, requiring low maintenance, having superior
reliability, a lack of mirror or beam path alignment, and they are
lightweight and generally compact.
[0184] In some embodiments of the invention spot arrays may be used
in order to ablate multiple pores at once. These spot arrays may,
in some cases, be created using microlenses and also be affected by
the properties of the laser. A larger wavelength may lead to a
smaller number of spots with increased spot diameter.
[0185] Turning to FIG. 7, a laser treatment system 700 is shown
according to an embodiment of the present invention.
[0186] Laser treatment system 700 is generally made up of control
system 702, optics and beam controls.
[0187] Control system 702 includes monitor1 704 and monitor2 706 as
well as keyboard 708 and mouse 710 to provide a user the ability to
interact and control with a host computer 724 running computer
programs. In many embodiments the computer programs running on host
computer 724 include control programs for controlling visible
spotting laser 712, laser head 714, laser cooling system 716,
system power supplies 718, laser power supply 720, and beam
transport optics 722.
[0188] Also provided for in this embodiment are depth control
subsystem 726, galvo mirrors 728, CCD Camera 730, visual microscope
732, focus subsystem 734, and beam delivery optics 736.
[0189] Preoperative measurement of ocular properties and
customization of treatment to an individual patient's needs is
beneficial in many embodiments. Preoperative measurement of ocular
properties may include measuring intraocular pressure (IOP),
scleral thickness, scleral stress/strain, anterior vasculature,
accommodative response, and refractive error. Measurement of
scleral thickness may include use of optical coherence tomography
(OCT). Measurement of scleral stress/strain may include using
Brillouin scattering, OCT elastography, photoacoustics (light plus
ultrasound). Measurement of anterior vasculature may include using
OCT or Doppler OCT. Measurement of refractive error may include
using the products such as the iTrace trademarked product from
Tracey Technologies Corp.
[0190] Intraoperative biofeedback loops may be important during the
procedure in order to keep the physician informed on the progress
of the procedure. Such feedback loops may include use of
topographical measurements and monitoring "keep away" zones such as
anterior ciliary arteries.
[0191] Biofeedback loops may include a closed-loop sensor to
correct for nonlinearity in the piezo scanning mechanism. The
sensor in some embodiments may offer real-time position feedback in
a few milliseconds and utilizing capacitive sensors for real-time
position feedback. Sensor/feedback apparatus may also perform
biological or chemical "smart sensing" to allow ablation of target
tissue and protect or avoid surrounding tissue. In some instances
this smart sensing may be accomplished by using a biochip
incorporation in a mask which is activated by light irradiation and
senses location, depth, size, shape, or other parameters of an
ablation profile. Galvo-optic assemblies are also contemplated in
some embodiments and may be used to gage numerous parameters of
laser steering and special function.
[0192] FIG. 8 illustrates an eye treatment map 800 according to an
embodiment of the present invention.
[0193] In the example embodiment sclera 802 is shown broken into
four quadrants. Limbus 804 is located aside from ablative pore
locations 806. As procedures in many embodiments of this invention
are completed by quadrants, only a first quadrant is shown however
each additional quadrant will have similar mapping.
[0194] FIGS. 9-11 illustrates exemplary pore matrices according to
preferred embodiments of the present invention. Patient eye 900 has
pupil 902, iris 904, and sclera 906. The pore matrices comprise a
plurality of pores 912 formed in first ablation pattern location
908 and second ablation pattern location 910.
[0195] In at least one embodiment, the connective tissue is the
sclera of the eye, and the delivery system comprises a
spacer/fixator configured to fix the delivery system relative to
the eye, and a corneal shield configured to be placed over the
cornea so as to block laser energy from being applied thereto. In
some embodiments the spacer/fixator may be detachable and/or
disposable. The delivery system may then form the pore matrix in
the sclera of the eye.
[0196] In at least one embodiment, the fixator includes a track
along which the delivery system can move relative to the eye. The
laser energy is selectively delivered to the scleral tissue
therethrough to form one or more matrices of the pore matrix at a
first location of the scleral tissue. Then, the delivery system is
relocated so that the laser energy may be selectively delivered to
the scleral tissue at a second location of the scleral tissue. In
this way, tessellated matrices may be formed.
[0197] The eye spacer/fixator is an adjustable dual cylinder shaped
apparatus that accommodates the anterior globe of the sclera where
a central cylinder excludes the cornea from a treatment zone and
where a periphery cylinder includes a scleral treatment zone up to
a 6-7 mm radius.
[0198] A scleral fixator may be attached to the inferior surface of
the dual cylinder assembly and may have four fixator prongs at
1:30-4:30-7:30-10:30 and the fixator may be detachable and
disposable from a treatment spacer bar.
[0199] In some embodiments there may be a corneal shield or plate
which can be tinted to protect associated portions of the eye.
[0200] In at least one embodiment, the delivery system contains a
sensor with a feedback configured to control depth, spot size and
dynamic control of the delivery system, and energy parameters of
the laser beam delivery.
[0201] In at least one embodiment, the delivery system contains a
transmitter communicatively coupled to a satellite unit that
communicates with the base unit--preferably by Radio frequency or
blue tooth or WIFI--regarding the tissue parameters and has a
dynamic control which communicates with the laser. Such
communication may include delivery parameters and shut off
features.
[0202] In some embodiments accessories may be provided for use with
the main system and device disclosed herein. These accessories may
include, in addition to the detachable and/or disposable eye
spacer/fixator described above, a disposable eye suction ring for
use with an eye module. The eye suction ring may be used in a
complementary or supplementary role with the eye spacer/fixator or,
in some embodiments, as a replacement.
[0203] In some embodiments a sterile "docking station" may be
provided for slit lamp-type configuration of the procedure.
Ablation Patterns
[0204] A method of use of the invention will now be discussed with
reference to the figures. As mentioned previously, the main purpose
of the method is to modify the biomechanical properties of the
tissue, particularly the sclera. This modification allows the pars
plicata of the ciliary body to move upward and inward on
contraction of the ciliary muscle, compensating for an increase in
choroidal and/or scleral stiffness with age and also potentially
enables corneal accommodation.
[0205] As shown in FIGS. 9 to 23, ablation patterns are formed in
various configurations on a patient's eye in accordance with the
invention.
[0206] Ablation patterns are formed by the laser beam during the
procedure. These are also referred to herein as pore matrices.
[0207] A pore matrix is formed of a plurality of perforations
scleral tissue of a patient. By being located in the scleral tissue
according to the pore matrix, the perforations interact with and
affect the fundamental mechanisms involved in the immunology,
biochemistry and molecular genetics of scleral tissue metabolism.
Indeed, tension or resilience in the scleral tissue is modified in
such a way that reduces natural degradation of physiological,
biomechanical, and biologic function of the tissues and organ. This
in turn helps restore mechanical efficiency of the natural
accommodative mechanism in optical focus and improves biomechanical
mobility to achieve this accommodative power.
[0208] The perforations may be formed by any means now known or
later developed. Such means may, for example, ablate, excise,
incise, vaporize, remodel or puncture the scleral tissue to create
the perforations. Although the pores or perforations in the scleral
tissue are generally described herein as being formed by ablating
the tissue using laser energy, it is contemplated that the
perforations could be formed using any desired surgical tool, such
as a diamond knife, ruby knife, or a radio frequency device, or a
nano device, robotics, a chemical application, electrical
application or a substrate wafer application.
[0209] In many embodiments the increase in pliability, resilience,
and restoration of viscoelastic properties caused by successful
ablation by the methods disclosed herein induces a "negative
stiffness" or Poisson's effect in the tissue. Poisson's effect is
described as the negative ratio of transverse to axial strain in a
material. That is to say, that when a material is compressed in one
three-dimensional direction that the material tends to expand in
the other two three-dimensional directions. Conversely, if a
material is stretched in one three-dimensional direction then the
material compresses in the other two three dimensional directions.
This is beneficial in the case where tissue has become stiff
because an increase in its ability to stretch or compress allows
for a greater range of movement and greater biomechanical
adaptability.
[0210] Ablation by the methods disclosed herein may be considered
to have a remodeling effect on the tissue being ablated since it is
inherently changing the properties of the tissue. This remodeling
effect creates mechanical isotropy in a minimum of two dimensions.
That is to say mechanical properties are identical in at least two
dimensions as a result of successful ablation.
[0211] In some cases, additional positive results may be observed
as a result of successful ablation. These may include improved
physiological interaction between pores including improved ion
exchange, separation catalysis, as well as improved biological,
chemical, and molecular purification and processing.
[0212] FIG. 12-FIG. 19 will now be described in detail. For each of
FIG. 12-FIG. 19, the region shown varies from Limbus to Ora Serrata
in one quadrant of the eye. The edge of the treatment zone is 0.5
mm from the limbus and nominally extends down 5.5 mm towards the
Ora Serrata. Eye dimensions vary with race, patient to patient and
with orientation around the globe (Temporal, Superior, Nasal,
Inferior).
[0213] The treatment region is divided radially into zones
correlating to anatomy. Zone 1: Ciliary body Pars Plicata; Zone 2:
Ciliary body Pars Plana; Zone 3: Transition of ciliary body to Ora
Serrata. This is described in further detail below in FIGS.
24A-C.
[0214] Aside from the exterior boundaries of the patterns, the main
differences in the patterns are regular grids (e.g. FIG. 12) versus
an "interspersed" grid (e.g. FIG. 14). In the regular grid, 4 pores
form the vertices of a square, whereas in the interspersed grid, 3
pores form the vertices of an equilateral triangle.
[0215] Turning to FIG. 12, a pore matrix map according to an
embodiment of the present invention is shown.
[0216] FIG. 12 generally shows distance map 1200 including excision
locations 1202. In some embodiments excision locations 1202 include
nine locations per oblique quadrant of the eye in a mathematical
diamond matrix pattern. Excision locations are set to six-hundred
micrometer sizes and are ablated using an Er:YAG laser. The process
is completed until each oblique quadrant has been completed. In
some embodiments the quadrants need not be oblique.
[0217] FIG. 13 illustrates a pore matrix according to an embodiment
of the present In some embodiments excision locations 1302 include
nine locations per quadrant of the eye in a mathematical angle
matrix pattern. Excision locations are set to six-hundred
micrometer sizes and are ablated using an Er:YAG laser. The process
is completed until each quadrant has been completed.
[0218] FIG. 14 illustrates a pore matrix according to an embodiment
of the present invention. In some embodiments excision locations
1402 include nine locations per quadrant of the eye in a
mathematical chevron matrix pattern. Excision locations are set to
six-hundred micrometer sizes and are ablated using an Er:YAG laser.
The process is completed until each quadrant has been
completed.
[0219] FIG. 15 illustrates a pore matrix according to an embodiment
of the present invention. In some embodiments excision locations
1502 include ten locations per quadrant of the eye in a
mathematical horizontal hexagonal matrix pattern. Excision
locations are set to six-hundred micrometer sizes and are ablated
using an Er:YAG laser. The process is completed until each quadrant
has been completed.
[0220] FIG. 16 illustrates a pore matrix according to an embodiment
of the present invention. In some embodiments excision locations
1602 include ten locations per quadrant of the eye in a
mathematical vertical hexagonal matrix pattern. Excision locations
are set to six-hundred micrometer sizes and are ablated using an
Er:YAG laser. The process is completed until each quadrant has been
completed.
[0221] FIG. 17 illustrates a pore matrix according to an embodiment
of the present invention. In some embodiments excision locations
1702 include fifteen locations per quadrant of the eye in a
mathematical triangular matrix pattern. Excision locations are set
to six-hundred micrometer sizes and are ablated using an Er:YAG
laser. The process is completed until each quadrant has been
completed.
[0222] FIG. 18 illustrates a pore matrix according to an embodiment
of the present invention. In some embodiments excision locations
1802 include fifteen locations per quadrant of the eye in a
mathematical wave matrix pattern. Excision locations are set to
six-hundred micrometer sizes and are ablated using an Er:YAG laser.
The process is completed until each quadrant has been
completed.
[0223] FIG. 19 illustrates a pore matrix according to an embodiment
of the present invention. In some embodiments excision locations
1902 include locations per quadrant of the eye in a mathematical
decagon matrix pattern. Excision locations are set to six-hundred
micrometer sizes and are ablated using an Er:YAG laser. The process
is completed until each quadrant has been completed.
[0224] Turning to FIG. 20-FIG. 21, examples of pores tracing out
"golden" spirals--clockwise, counterclockwise and combined are
shown. A golden spiral is a logarithmic spiral that grows by a
factor of .phi. (the golden number; .phi.=1.618) for each quarter
turn of the spiral. This is a form of spiral commonly found in
nature. This "golden" spiral pore matrix is the preferred
embodiment. In other embodiments other types of spirals could be
used as well.
[0225] Spiral and circle patterns in accordance with the invention
generally demonstrate a transition from quadrant-based treatment to
complete circumferential treatment.
[0226] FIG. 20 illustrates pore matrices in spiral form according
to embodiments of the present invention. According to the example
embodiment patterns 2000 are made of pores 2002.
[0227] FIG. 21 illustrates a pore matrix in spiral form according
to an embodiment of the present invention. According to the example
embodiment patterns 2100 are made of spirals 2102. Spirals 2102 are
in turn made of pores (not shown in the current embodiment).
[0228] FIG. 22 illustrates a pore matrix in concentric circular
form according to an embodiment of the present invention. According
to the example embodiment patterns 2200 are made of pores 2202.
[0229] These concentric circles are shown emanating from limbus to
ora serrata. Each circle shown here has pores with equal angular
spacing. In some embodiments patterns may also be created with
equal pore to pore lateral spacing. In some embodiments every other
circle shifted by one half of the pore spacing rotationally to
produce an "interspersed" pattern.
[0230] FIG. 23 illustrates a pore matrix in interspersed circular
form according to an embodiment of the present invention. According
to the example embodiment patterns 2300 are made of pores 2302.
[0231] The pore matrix is such that the fundamental biomechanical
properties of the scleral tissue may be improved by formation of
the pore matrix therein. The pore matrix may consist of one or more
regularly spaced arrays of perforations. The pore matrix may also
comprise one or more matrices, each matrix comprising one or more
regularly spaced arrays of perforations. That is, the pore matrix
is comprised of one or more matrices, which is comprised of one or
more regularly spaced arrays of perforations in the scleral tissue.
Various pore matrices are contemplated, some non-limiting examples
of which are described above. Other exemplary pore matrices are
described in the materials appended hereto and are hereby
incorporated by reference in their entireties.
[0232] The pore matrix may be a tessellated pore matrix. That is,
the pore matrix may comprise a plurality of matrices repeating with
no gaps and no overlap. Although patterns shown in the drawings are
discretized, showing a specific number of ablations in specific
patterns, the drawings are not exhaustive. As such, numerous other
regular or interspersed grid patterns are contemplated and
different spirals, concentric circles, three dimensional, and even
other irregular or perturbed patterns are contemplated. Pore
characteristics may be highly variable in additional embodiments of
the invention, not specifically described here.
[0233] In some embodiments, the pores or perforations may extend
through the entire depth or thickness of the scleral tissue, or
substantially therethrough. Accordingly, the tissue may be ablated
through an infinite number of planes of the tissue. Alternatively,
the pore matrix may be formed in multiple discrete planes of the
scleral tissue. Indeed, it subsurface pore matrices are
specifically contemplated. Thus, for example, pore matrices of
n.times.m.times.1 matrices may be formed.
[0234] Additionally, the perforations may be formed according to
different sizes and shapes. These may include cylindrical,
cone-shaped, square, rectangular, pyramidal, and others.
[0235] Turning to FIG. 24A, an illustration of an accommodated eye
2401 and a disaccommodated eye 2402 and associated muscle movement
of the eye is shown. FIG. 24A generally shows ciliary muscle 2404,
lens 2406, pars plicata portion 2408 of ciliary body, cornea 2410,
zonules 2412, and sclera 2414. In FIG. 24A, accommodated eye 2401
and disaccomodated eye 2402 are shown, the changes between the two
described below.
[0236] The relaxed, or disaccommodated eye 2402 is shown on the
right. The ciliary muscle 2402 is relaxed and the zonules 2412 are
pulled taut, flattening (thinning) the lens 2406 for distance
vision and lower power.
[0237] The accommodated eye 2401 is shown on the left. Here, the
ciliary muscle 2404 is contracted, relaxing the tension on the
zonules 2412 and allowing the crystalline lens 2406 to take its
more natural, curved shape for near vision. Lens 2406 in this
configuration may also be referred to as steeper or thicker. Also,
the pars plicata 2408 of the ciliary body moves inward.
[0238] Zonules 2412 are variously known as suspensory ligaments,
zonules of Zinn, and zonnular apparatus. Zonular fibers that attach
to the lens are anterior, central, and posterior. Ciliary muscle
2402 is contained within the ciliary body.
[0239] FIG. 24B illustrates the three parts of ciliary muscle and
their relation to one another in the eye. Ciliary body 2414
contains ciliary muscle. Ciliary muscle includes Circular Ciliary
Muscle Fibers 2416, Radial (Oblique) Ciliary Muscle Fibers 2418,
Longitudinal (Meridonal) Ciliary Muscle Fibers (aka Bruke's Muscle)
2420, and "Epichoroidal Star" attachment 2422. Also shown is sclera
spur 2424 of sclera 2414.
[0240] These muscles are generally grouped into three types,
circular, radial and longitudinal. The radial and longitudinal
muscle fibers terminate in the scleral spur 2424. The longitudinal
muscle fibers terminate in "epichoroidal stars" 2422 for attachment
to the choroid layer 2426 at the ora serrata 2428.
[0241] FIG. 24C is corneo-scleral shell with the ciliary body 2414
showing contraction of ciliary muscle and its effect on the eye.
Shown in FIG. 24C is the increase in the bundle cross section of
Circular Ciliary Muscle Fibers 2416 as the contraction of ciliary
muscles stretches choroid 2426 and causes inward/upward movement of
pars plicata 2408, relaxing zonules 2412. More particularly, when
the ciliary muscle contracts, the longitudinal fibers stretch the
choroid and pull ora serrata 2428 up. The end of the ciliary body
2414 close to the scleral spur 2424 is called the pars plicata
2408. As the ciliary muscle contracts, the pars plicata 2408 moves
inward and upward. This relaxes the tension on the zonules 2412
attached to the crystalline lens 2406, allowing lens 2406 to take a
steeper shape for near vision. As discussed above, aging generally
impairs the biomechanical properties of the scleral tissue and so
impedes the above described functionality of the sclera with
respect to accommodation. Formation of the aforementioned pore
matrices in the scleral tissue in accordance with the embodiments
described herein restore the biomechanical properties of the
scleral tissue that were impaired by age.
[0242] Ablation creates pliable matrix zones in the sclera and in
the example embodiment micro-excisions are created in three
critical zones over the ciliary complex. However, matrix zones are
not limited to two dimensional matrices. In many embodiments of the
invention the matrix zones are three dimensional. Also provided are
treatments wherein locations may be reached within the tissue
without ablating regions above the tissue. That is, a location with
x, y, z coordinates in the tissue may be reached without ablating
any or all tissue in the three dimensional space to get to the x,
y, z coordinate location.
[0243] In some embodiments the living tissue matrix creates a
hyperbolic plane of tissue having a differential tissue plane
within a plurality of pore matrices being anisotropic, tessellated
and within a mathematical array exists. Additionally, particular
matrices chosen may effect biological or biomechanical
reactions.
[0244] In some embodiments pores may be nanopores which are less
than two nanometers in diameter, neopores which are between two and
fifty nanometers, or macropores which ware greater than fifty
nanometers in diameter. Pores may generally be between one and one
hundred nanometers.
[0245] Some embodiments of the invention provide for a high surface
to volume ratio ordered uniform pore structure throughout a
plurality of planes. In general there is a specificity of pore
size, shape and distribution in the matrix used in an embodiment
and pores are specifically and mathematically arranged in a
matrix.
[0246] In some embodiments the specificity of a pore pattern may be
a fractal. In some embodiments the specificity of a pore wall
morphology is integral. Pore walls contain an inner wall, an outer
wall, and interstitial space which may occur at a plurality of
depths, angles, and planes through several layers of tissue.
[0247] Some pre configurations have a three dimensional
architecture of particle aggregates. The biomechanical properties
of a tissue cross section where matrices are placed may be effected
by porosity such as the equation f=VfNt or F=Va+Vu/Vs+Va+Vw where
there is a surface volume ratio diameter and depth distribution of
the pore relationship within the plurality of matrices of
Fv=-(dV/dD) where V=pore Volume and D=pore Diameter.
[0248] As another example, in the ear, the surgical laser system
may be used to treat the tympanic membrane, the crista ampullaris,
the cochlear, the cochlear duct, and hair cells. As another
example, the surgical laser system may be used to treat tissue of
the kidneys or tissue of the ovaries. As another example, the
surgical laser system may be used to treat large aponeuroses, such
as lumbosacral fascia, abdominal raphe, and neural sheath in the
spinal cord. As yet another example, the surgical laser system may
be used to treat bones, cartilage, ligaments, and tendons. As still
another example, the surgical laser system may be used to treat the
brain, such as dura matter of the brain and the bony surroundings
of the brain. As another example, the surgical laser system may be
used to treat lymph node CT or spleen CT. As another example, the
surgical laser system may be used to treat vascular vessels and/or
the heart as well as the surrounding tissue such as the
pericardium. As a further example, the surgical laser system may be
used to treat muscles.
[0249] FIG. 25 shows a configuration where the beam delivery system
scans over the eye in a "goniometric" motion--that is the beam
delivery system traces an arc with an offset center of curvature.
In this case, the center of curvature is at the center of the
treated eye. This allows the nominal line of sight from the beam
delivery system to maintain perpendicularity to the surface of the
sclera. The motion of the beam delivery system can be along either
or both of two axes, labeled with the alpha and beta angles in the
drawing. The galvo scanners can be used to scan locally within an
angular neighborhood of theta, to place spots in the (annular)
treatment zone while maintaining perpendicularity of the line of
sight to the scleral surface.
[0250] The effects of ablation may be seen in many of the
structures of the eye. For instance, the ciliary muscle is a ring
of striated smooth muscle that controls accommodation for viewing
objects at varying distances. In simpler terms, it helps in
focusing of the eye. Some of the mechanisms used include regulating
flow of aqueaous humour into Schlemm's canal and changing the shape
of the lens within the eye (but not the pupil size which is
affected by a different muscle). Ablation of scleral tissue as
performed in numerous embodiments in this description causes a
decrease in scleral resistive forces. This decrease in scleral
resistive forces in turn increases ciliary muscle resultant forces
and allows for improved focusing and restoration of dynamic
accommodation within the eye.
[0251] In some instances near and intermediate vision and both
uncorrected and distance corrected vision improves as a result of
the methods described herein.
Healing Inhibition
[0252] The perforations may have inner walls that are spaced from
each other a distance that alters the fundamental mechanisms
involved in the immunology, biochemistry and molecular genetics of
scleral tissue metabolism in such a way as to inhibit normal tissue
healing, repair, or regeneration to prevent total healing of the
perforations in the scleral tissue. The inner walls of the
perforations may be spaced from each other by a distance greater
than 400 .mu.m. It is also contemplated that the inner walls of the
perforations may be spaced from each other by a distance greater
than 600 .mu.m. It is also contemplated that the inner walls of the
perforations may be spaced from each other by a distance greater
than 200 .mu.m. It is also contemplated that the size of the
perforations can range from 0.001 to 1 um. Preferably, the
perforation size is determined by the proportion of removed tissue
to remaining tissue in the target tissue. For the perforations of
the pore matrix, there may be a positive correlation of the
perforation area to the residual interstitial tissue--in other
words, the perforation may comprise a complete negative space.
Additionally, for the perforations of the pore matrix, the
perforation may comprise a negative, or reverse pattern, where the
perforation may comprise a negative space encapsulating a positive
space--in other words, the perforation may comprise an outline of
remaining interstitial tissue. Preferably, such reverse
perforations comprise rings surrounding interstitial tissue.
[0253] The perforations may be filled with a scarring inhibitor
substance such as a porous collagen-glycosaminoglican scaffold. An
example of such a porous collagen-glycosaminoglican scaffold is
made by Mediking under the trade name OccuusGen. Alternatively, the
perforations may be filled with a biological glycoprotein or a
synthetic glycoprotein. As another alternative, the perforations
may be filled via the application of a biologically compatible
product, which can be in the form of a liquid, a gel, or a porous
solid. The perforations may also be treated with a sealant. An
example of such a sealant is made by Johnson and Johnson under the
tradename Band-Aid.RTM. brand liquid bandage; and a similar product
is made by Spenco under the tradename 2nd Skin.RTM. and OcuSeal.TM.
Liquid Ocular BandageAs a further alternative, the perforations may
be filled via application or treatment to facilitate an ionic
reaction, chemical reaction, photonic reaction, organic reaction,
inorganic reaction, electronic reaction, or a combination of these
reactions to disrupt normal tissue healing. One such preferred
embodiment would be to utilize anti fibrotic or other wound healing
prevention agent in the form of a collagenous contact lens or
biodegradable material. Another such preferred embodiment would be
to utilize a biochemical to inhibit wound healing or a biological
synthetic to inhibit wound healing.
[0254] The enablements described in detail above are considered
novel over the prior art of record and are considered critical to
the operation of at least one aspect of the invention and to the
achievement of the above described objectives. The words used in
this specification to describe the instant embodiments are to be
understood not only in the sense of their commonly defined
meanings, but to include by special definition in this
specification: structure, material or acts beyond the scope of the
commonly defined meanings. Thus if an element can be understood in
the context of this specification as including more than one
meaning, then its use must be understood as being generic to all
possible meanings supported by the specification and by the word or
words describing the element.
[0255] The definitions of the words or drawing elements described
herein are meant to include not only the combination of elements
which are literally set forth, but all equivalent structure,
material or acts for performing substantially the same function in
substantially the same way to obtain substantially the same result.
In this sense it is therefore contemplated that an equivalent
substitution of two or more elements may be made for any one of the
elements described and its various embodiments or that a single
element may be substituted for two or more elements in a claim.
[0256] Changes from the claimed subject matter as viewed by a
person with ordinary skill in the art, now known or later devised,
are expressly contemplated as being equivalents within the scope
intended and its various embodiments. Therefore, obvious
substitutions now or later known to one with ordinary skill in the
art are defined to be within the scope of the defined elements.
This disclosure is thus meant to be understood to include what is
specifically illustrated and described above, what is conceptually
equivalent, what can be obviously substituted, and also what
incorporates the essential ideas.
[0257] The scope of this description is to be interpreted only in
conjunction with the appended claims and it is made clear, here,
that the named inventor believes that the claimed subject matter is
what is intended to be patented.
* * * * *