U.S. patent application number 15/227410 was filed with the patent office on 2017-01-05 for preformed lens systems and methods.
This patent application is currently assigned to AMO Development, LLC. The applicant listed for this patent is AMO Development, LLC. Invention is credited to Paul Bradford, Guang-ming Dai, Dan Summers.
Application Number | 20170000645 15/227410 |
Document ID | / |
Family ID | 47790540 |
Filed Date | 2017-01-05 |
United States Patent
Application |
20170000645 |
Kind Code |
A1 |
Summers; Dan ; et
al. |
January 5, 2017 |
PREFORMED LENS SYSTEMS AND METHODS
Abstract
Systems, methods, computer program products, and kits involving
deformation mechanisms are provided for the removal of corneal
tissue in optical vision treatments. According to exemplary
embodiments, deformation mechanisms may be used in combination with
the administration of femtosecond photoalteration lasers to create
or define volumetric tissue portions for such removal.
Inventors: |
Summers; Dan; (Santa Clara,
CA) ; Dai; Guang-ming; (Fremont, CA) ;
Bradford; Paul; (San Jose, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AMO Development, LLC |
Santa Ana |
CA |
US |
|
|
Assignee: |
AMO Development, LLC
Santa Ana
CA
|
Family ID: |
47790540 |
Appl. No.: |
15/227410 |
Filed: |
August 3, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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13773913 |
Feb 22, 2013 |
9427357 |
|
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15227410 |
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61601865 |
Feb 22, 2012 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 2018/20351
20170501; A61F 2/16 20130101; A61F 2009/00872 20130101; A61B
2018/2055 20130101; A61F 9/009 20130101; A61F 9/00827 20130101;
A61F 9/00745 20130101; A61F 2009/0087 20130101; A61F 9/008
20130101 |
International
Class: |
A61F 9/007 20060101
A61F009/007; A61F 9/009 20060101 A61F009/009; A61F 2/16 20060101
A61F002/16; A61F 9/008 20060101 A61F009/008 |
Claims
1. A method of providing a surgical treatment to an eye of a
patient, the method comprising: positioning a corneal deformation
mechanism against an anterior surface of the eye of the patient, so
as to induce a first intended biomechanical conformation within a
corneal stromal tissue of the eye; delivering a first photoaltering
energy protocol to the eye while the corneal stromal tissue is in
the first intended biomechanical conformation, so as to incise the
corneal stromal tissue along a first target surface; positioning
the corneal deformation mechanism against the anterior surface of
the eye of the patient, such that the corneal stromal tissue of the
eye assumes a second intended biomechanical conformation different
from the first intended biomechanical conformation; delivering a
second photoaltering energy protocol to the eye while the corneal
stromal tissue is in the second intended biomechanical
conformation, so as to incise the corneal stromal tissue along a
second target surface different from the first target surface; and
removing a portion of corneal stromal tissue bounded by the first
and second target surfaces, wherein the corneal deformation
mechanism comprises an applanation assembly that provides a first
shape configuration and a second shape configuration, such that
when in the first shape configuration, the applanation assembly is
shaped to induce the first intended biomechanical conformation
within the corneal stromal tissue, and when in the second shape
configuration, the applanation assembly is shaped to induce the
second intended biomechanical conformation within the corneal
stromal tissue.
2. The method according to claim 1, wherein the corneal deformation
mechanism comprises an applanation plate and a removable body, the
removable body constructed of a material having an index of
refraction of about 1.377.
3. The method according to claim 2, wherein the removable body is
removed from the applanation plate during the first positioning and
delivering steps, and wherein the removable body is coupled with
the applanation plate and contacts the anterior surface of the eye
during the second positioning and energy delivery steps.
4. The method according to claim 2, wherein the removable body is
coupled with the applanation plate and contacts the anterior
surface of the eye during the first positioning and energy delivery
steps, and wherein the removable body is removed from the
applanation plate during the second positioning and delivering
steps.
5. The method according to claim 1, wherein the step of removing
the portion of corneal stromal tissue comprises emulsifying the
portion of corneal stromal tissue with an ultrasonic device.
6. The method according to claim 5, wherein the step of removing
the portion of corneal stromal tissue comprises aspirating the
emulsified tissue.
7. The method according to claim 1, wherein the step of removing
the portion of corneal tissue comprises aspirating the portion of
tissue through a corneal incision.
8. The method according to claim 1, further comprising removing a
natural crystalline lens from the eye of the patient.
9. The method according to claim 1, further comprising replacing a
natural crystalline lens of the eye of the patient with an
artificial intraocular lens implant.
10. A method of providing a surgical treatment to an eye of a
patient, the method comprising: positioning an energy transmission
assembly against an anterior surface of the eye of the patient, so
as to induce a first intended biomechanical conformation within a
corneal stromal tissue of the eye; delivering a first photoaltering
energy protocol through the energy transmission assembly to the eye
while the corneal stromal tissue is in the first intended
biomechanical conformation, so as to incise the corneal stromal
tissue along a first target surface; positioning the energy
transmission assembly against the anterior surface of the eye of
the patient, such that the corneal stromal tissue of the eye
assumes a second intended biomechanical conformation different from
the first intended biomechanical conformation; delivering a second
photoaltering energy protocol through the energy transmission
assembly to the eye while the corneal stromal tissue is in the
second intended biomechanical conformation, so as to incise the
corneal stromal tissue along a second target surface different from
the first target surface; and removing a portion of corneal stromal
tissue bounded by the first and second target surfaces, wherein the
energy transmission assembly provides a first shape configuration
and a second shape configuration, such that when in the first shape
configuration, the energy transmission assembly is shaped to induce
the first intended biomechanical conformation within the corneal
stromal tissue, and when in the second shape configuration, the
energy transmission assembly is shaped to induce the second
intended biomechanical conformation within the corneal stromal
tissue.
11. The method according to claim 10, wherein the energy
transmission assembly comprises an applanation plate and a
removable body, the removable body constructed of a material having
an index of refraction of about 1.377.
12. The method according to claim 11, wherein the removable body is
removed from the applanation plate during the first positioning and
delivering steps, and wherein the removable body is coupled with
the applanation plate and contacts the anterior surface of the eye
during the second positioning and energy delivery steps.
13. The method according to claim 11, wherein the removable body is
coupled with the applanation plate and contacts the anterior
surface of the eye during the first positioning and energy delivery
steps, and wherein the removable body is removed from the
applanation plate during the second positioning and delivering
steps.
14. The method according to claim 10, wherein the step of removing
the portion of corneal stromal tissue comprises emulsifying the
portion of corneal stromal tissue with an ultrasonic device.
15. The method according to claim 14, wherein the step of removing
the portion of corneal stromal tissue comprises aspirating the
emulsified tissue.
16. The method according to claim 10, wherein the step of removing
the portion of corneal tissue comprises aspirating the portion of
tissue through a corneal incision.
17. The method according to claim 10, further comprising removing a
natural crystalline lens from the eye of the patient.
18. The method according to claim 10, further comprising replacing
a natural crystalline lens of the eye of the patient with an
artificial intraocular lens implant.
19-22. (canceled)
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application is a divisional application of U.S. patent
application Ser. No. 13/773,913, filed on Feb. 22, 2013, which
claims priority to U.S. Application No. 61/601,865, filed on Feb.
22, 2012, which is related to U.S. patent application Ser. Nos.
11/677,504 and 12/471,090, filed Feb. 21, 2007 and May 22, 2009
respectively, the contents of which are incorporated herein by
reference for all purposes.
BACKGROUND OF THE INVENTION
[0002] In general, embodiments of the present invention relate to
the field of vision treatment. Exemplary embodiments relate to
laser eye surgery devices, systems, and methods for selectively
altering refractive properties of corneas having regular and/or
irregular optical defects or shapes, often by directing energy into
the corneal stroma.
[0003] Laser eye surgery systems and methods are now used to
correct or treat defects in vision, often using a technique known
as ablative photodecomposition. In general, this technique applies
a pattern of laser radiation to an exposed corneal tissue so as to
selectively remove and resculpt the cornea. The pattern of laser
energy often includes a series of discrete laser pulses from an
excimer laser, with the locations, sizes, and/or numbers of pulses
of the pattern being calculated to achieve a desired volumetric
resculpting of the cornea, and to thereby create enhanced optical
properties or treat optical defects.
[0004] Many patients suffer from optical defects which are not
easily treated using standard glasses and contact lenses. Glasses
and contacts often treat only regular or spherical and cylindrical
refractive errors of the eye. Wavefront diagnostic techniques have
been developed to measure irregular refractive errors, and these
techniques have proven highly useful in determining customized
refractive prescriptions for these patients. The flexibility of
laser photorefractive decomposition offers hope to these patients,
as this technique can be used to resculpt the eyes to correct both
regular and irregular refractive errors. By combining laser eye
surgery techniques with wavefront diagnostic approaches, it is
often possible to achieve visual acuity measurements of 20/20 or
better for many patients.
[0005] Early laser eye surgery treatments often involved the
removal of the epithelial layer before changing the shape of the
underlying corneal tissue. The epithelial layer tends to regrow,
whereas volumetric resculpting of the underlying stroma can provide
long-lasting effects. Corneal resculpting techniques involving
mechanical abrasion or laser ablation of the epithelial layer so as
to expose the underlying stroma for volumetric photoablative
decomposition are often referred to as photorefractive keratectomy
("PRK"), and PRK remains a good option for many patients. In the
last several years, alternative techniques involving formation of a
flap of corneal tissue (including the epithelial layer) have gained
in popularity. Such techniques are sometimes popularly referred to
"flap-and-zap," or laser in situ keratomileusis ("LASIK"). LASIK
and related variations often have the advantage that vision can be
improved within a few hours (or even minutes) after surgery is
complete. LASIK flaps are often formed using mechanical cutting
blades or microkeratomes, and the flap of epithelial tissue can be
temporarily displaced during laser ablation of the stroma. The flap
can reattach to the underlying stroma quite quickly, and the
patient need not wait for epithelial tissue regrowth to experience
the benefits of laser resculpting, so that these procedures are
safe and highly effective for many patients.
[0006] A variety of alternative refraction altering techniques have
also been proposed. In particular, focusing of femtosecond laser
energy within the stroma so as to ablate a volume of intrastromal
tissue has been proposed. By scanning the focal spot within an
appropriate volume of the stromal tissue, it might be possible to
vaporize the volume so as to achieve a desired refractive
alteration. Despite possible advantages of intrastromal volumetric
ablation techniques, these approaches have not yet gained the
popularity of LASIK and/or PRK. Intrastromal femtosecond ablation
techniques have, however, begun to gain popularity as a method for
incising the cornea so as to form the flap of corneal tissue in
LASIK and related procedures. Unfortunately, this combined approach
often involves the use of both a fairly expensive intrastromal
femtosecond laser for incising the corneal tissues, and then an
excimer laser for resculpting the exposed stroma. The combined use
of these two separate, fairly complex and/or expensive laser
systems may limit the acceptability and benefits of these new
refractive laser eye surgery techniques.
[0007] Hence, although current vision treatment modalities deliver
real benefits to patients in need thereof, further advancement to
provide to improved devices, system, and methods for laser eye
surgery is desired. Embodiments of the present invention provide
solutions that address certain inefficiencies or shortcomings which
may be associated with known techniques, and hence provide answers
to at least some of these outstanding needs.
BRIEF SUMMARY OF THE INVENTION
[0008] Embodiments of the present invention encompass the
manufacture of pre-cut lenses and the use of such lenses in
combination with laser surgical techniques, including femtosecond
laser photodisruption or photoalteration treatments. These
techniques further expand the capabilities of lasers, and allow
their use for both incising and refractively altering the eye. In
many instances, embodiments disclosed herein are suitable for the
treatment or correction of regular refractive errors and an
irregular refractive alterations (such as correcting an irregular
refractive error of the eye), without having to resort to two
separate laser systems.
[0009] Exemplary systems and methods involve the formation of two
regular flap-type cuts or disruption patterns, where one pattern is
formed using a pre-cut lens, and another pattern is formed without
using the pre-cut lens. Tissue between the disruption patterns,
which may be present as an envelope of a certain volume of stroma,
can be removed, so as to alter the shape of the eye. In some cases,
a femtosecond laser can be used to perform the photodisruption,
thus providing an easy, precise, and effective approach to
effective refractive surgery. Optionally, the photodisruption
patterns can be created as a flat surface configuration. In some
instances, the pre-cut lens includes a material having an index of
refraction that matches the index of refraction of the corneal
stroma. The pre-cut lens may be placed over the surface of the
cornea, or onto a patient interface (PI). In some instances, the
pre-cut lens can be manufactured according to principles used for
the manufacture of intraocular lenses. By using the pre-cut lens,
it is possible to provide spatially precise disruption patterns in
such a way so as to avoid some of the difficulties that may be
associated with other techniques for controlling a laser focal
point in three dimensions to cut an envelope of tissue volume. For
example, software control of arbitrary focusing of each laser pulse
may be difficult to implement in certain situations. In contrast,
the use of a preformed lens to create a flat surface disruption can
be easier to implement. As noted elsewhere herein, by creating two
cuts or disruption patterns (one using a preformed lens and one
without using the lens), it is possible to define an amount of
tissue for removal that approximates the volume and shape of the
lens, thus leaving a void or space in the stroma that approximates
the volume and shape of the lens.
[0010] The present invention generally provides improved devices,
systems, and methods for laser eye surgery. In many embodiments,
the invention will make use of femtosecond (or optionally
picosecond) lasers and their ability to selectively ablate tissues
within the cornea of an eye. By focusing energy from these lasers
at a focal spot within a corneal stroma, and by scanning the spot
along a surface, such lasers can quickly and accurately incise the
corneal tissues along that surface. Rather than attempting to rely
on volumetric intrastromal tissue vaporization, embodiments of the
invention may largely (or even primarily) employ mechanical removal
of tissues bordered by a laser incision surface. Advantageously,
large variations in depth of the focal spot from a plane (or other
surface, such as a sphere or the like) may be avoided by
pre-shaping the corneal tissues using a tissue-shaping surface.
[0011] By selecting an appropriate tissue-shaping surface, for
example based on a regular and/or irregular refractive error of the
eye, and by calculating an appropriate tissue incision surface so
as to correct or treat the regular and/or irregular errors, the
corneal reshaping may mitigate both regular and irregular
refractive defects. In some cases, the laser treatment may be
completed in less than 100 seconds. In some cases, the treatment
may be completed in less than 50 seconds. In some cases, the
treatment may be completed in less than 30 seconds. In some cases,
the treatment may be completed in less than 10 seconds. These time
durations refer to the period of time between initiation of and
completion of the laser ablation.
[0012] In some aspects, embodiments of the present invention
provide systems and methods for altering refraction of an eye. For
example, the eye may have a refractive error, and therefore may
potentially benefit from receiving an optical treatment, the goal
of providing a desired refractive alteration. In many embodiments,
the desired refractive alteration of the eye may involve the
correction of refractive defects, typically based on wavefront
measurements of the eye. An appropriate tissue-shaping surface or
deformation mechanism may be selected by choosing or manufacturing
a shaping body, which can correspond to a desired refractive
treatment for the eye. In exemplary embodiments, a tissue-shaping
body may include a material transmissive of the laser energy used
to form the spot. In many embodiments, tissue will be at least
partially mechanically excised from between two disruption
patterns. Tissue may be mechanically excised from between these two
laser-formed or photoaltered tissue surfaces so that the eye has
enhanced refractive characteristics when the two tissue surfaces
engage each other, and without having to wait for epithelial
regrowth.
[0013] In some aspects, embodiments may provide methods for
customized correction of an eye. Exemplary methods may include
measuring regular and/or irregular refractive errors of the eye.
Aspects of the deformation mechanism or shaping body can be
determined in response to the measured refractive error of the eye,
and tissue of the eye can be incised by scanning a laser spot
through the tissue along one or more laser target surfaces. Tissue
bordered by the laser target surfaces can be mechanically excised
so as to mitigate the regular and/or irregular refractive errors of
the eye. In some cases, embodiments of the present invention
encompass systems, kits, and computer program products for altering
refraction of an eye.
[0014] In some aspects, embodiments provide a deformation mechanism
or tissue-shaping body for use with a system to alter refraction of
an eye. The eye will often have a refractive error, the system
including a support for positioning the deformation mechanism or
shaping body along an optical path from a laser and beam scanning
optics for scanning along a target surface to incise tissue of the
eye when the eye engages the body such that removal along the
incised tissue surface mitigates the errors of the eye. The
deformation mechanism or body may include a material transmissive
of light from the laser, and a tissue shaping surface defined by
the material.
[0015] Embodiments of the present invention can be readily adapted
for use with existing laser systems and other optical treatment
devices. Although system, software, and method embodiments of the
present invention are described primarily in the context of a laser
eye surgery system, it should be understood that embodiments of the
present invention may be adapted for use in or in combination with
alternative eye treatment procedures, systems, or modalities, such
as spectacle lenses, intraocular lenses, accommodating IOLs,
contact lenses, corneal ring implants, collagenous corneal tissue
thermal remodeling, corneal inlays, corneal onlays, other corneal
implants or grafts, and the like. Relatedly, systems, software, and
methods according to embodiments of the present invention are well
suited for customizing any of these treatment modalities to a
specific patient. Thus, for example, embodiments encompass custom
preformed lenses, intraocular lenses, custom contact lenses, custom
corneal implants, and the like, which can be configured to treat or
ameliorate any of a variety of vision conditions in a particular
patient based on their unique ocular characteristics or
anatomy.
[0016] In some instances, these techniques can be carried out in
conjunction with treatments provided by any of a variety of laser
devices, including without limitation the WaveScan.RTM. System and
the STAR 54.RTM. Excimer Laser System both by Abbott Medical Optics
Inc., the WaveLight.RTM. Allegretto Wave.RTM. Eye-Q laser, the
Schwind Amaris.TM. lasers, the 217P excimer workstation by
Technolas PerfectVision GmbH, the Mel 80.TM. laser by Carl Zeiss
Meditec, Inc., and the like.
[0017] In one aspect, embodiments of the present invention
encompass methods for providing a surgical treatment to an eye of a
patient. Methods may include, for example, positioning a corneal
deformation mechanism against an anterior surface of the eye of the
patient, so as to induce a first intended biomechanical
conformation within a corneal stromal tissue of the eye, and
delivering a first photoaltering energy protocol to the eye while
the corneal stromal tissue is in the first intended biomechanical
conformation, so as to incise the corneal stromal tissue along a
first target surface. Methods may also include positioning the
corneal deformation mechanism against the anterior surface of the
eye of the patient, such that the corneal stromal tissue of the eye
assumes a second intended biomechanical conformation different from
the first intended biomechanical conformation, and delivering a
second photoaltering energy protocol to the eye while the corneal
stromal tissue is in the second intended biomechanical
conformation, so as to incise the corneal stromal tissue along a
second target surface different from the first target surface.
Further, methods may include removing a portion of corneal stromal
tissue bounded by the first and second target surfaces. According
to some embodiments, the corneal deformation mechanism includes an
applanation assembly that provides a first shape configuration and
a second shape configuration, such that when in the first shape
configuration, the applanation assembly is shaped to induce the
first intended biomechanical conformation within the corneal
stromal tissue, and when in the second shape configuration, the
applanation assembly is shaped to induce the second intended
biomechanical conformation within the corneal stromal tissue. In
some cases, the corneal deformation mechanism includes an
applanation plate and a removable body. The removable body may be
constructed of a material having an index of refraction of about
1.377, for example. According to some embodiments, the removable
body is removed from the applanation plate during the first
positioning and delivering steps, and the removable body is coupled
or engaged with the applanation plate and contacts the anterior
surface of the eye during the second positioning and energy
delivery steps. In some instances, the removable body is coupled or
engaged with the applanation plate and contacts the anterior
surface of the eye during the first positioning and energy delivery
steps, and the removable body is removed from the applanation plate
during the second positioning and delivering steps. The step of
removing the portion of corneal stromal tissue may involve
emulsifying the portion of corneal stromal tissue with an
ultrasonic device. In some cases, the step of removing the portion
of corneal stromal tissue involves aspirating the emulsified
tissue. In some cases, the step of removing the portion of corneal
tissue involves aspirating the portion of tissue through a corneal
incision. Methods may also include removing a natural crystalline
lens from the eye of the patient. Some methods may include
replacing a natural crystalline lens of the eye of the patient with
an artificial intraocular lens implant.
[0018] In another aspect, embodiments of the present invention
encompass methods of providing a surgical treatment to an eye of a
patient that include positioning an energy transmission assembly
against an anterior surface of the eye of the patient, so as to
induce a first intended biomechanical conformation within a corneal
stromal tissue of the eye, and delivering a first photoaltering
energy protocol through the energy transmission assembly to the eye
while the corneal stromal tissue is in the first intended
biomechanical conformation, so as to incise the corneal stromal
tissue along a first target surface. Methods may also include
positioning the energy transmission assembly against the anterior
surface of the eye of the patient, such that the corneal stromal
tissue of the eye assumes a second intended biomechanical
conformation different from the first intended biomechanical
conformation, and delivering a second photoaltering energy protocol
through the energy transmission assembly to the eye while the
corneal stromal tissue is in the second intended biomechanical
conformation, so as to incise the corneal stromal tissue along a
second target surface different from the first target surface.
Further, methods may include removing a portion of corneal stromal
tissue bounded by the first and second target surfaces. According
to some embodiments, the energy transmission assembly provides a
first shape configuration and a second shape configuration, such
that when in the first shape configuration, the energy transmission
assembly is shaped to induce the first intended biomechanical
conformation within the corneal stromal tissue, and when in the
second shape configuration, the energy transmission assembly is
shaped to induce the second intended biomechanical conformation
within the corneal stromal tissue. In some cases, the energy
transmission assembly includes an applanation plate and a removable
body. The removable body may be constructed of a material having an
index of refraction of about 1.377, for example. According to some
methods, the removable body is removed from the applanation plate
during the first positioning and delivering steps, and the
removable body is coupled or engaged with the applanation plate and
contacts the anterior surface of the eye during the second
positioning and energy delivery steps. In some cases, the removable
body is coupled or engaged with the applanation plate and contacts
the anterior surface of the eye during the first positioning and
energy delivery steps, and the removable body is removed from the
applanation plate during the second positioning and delivering
steps. According to some embodiments, the step of removing the
portion of corneal stromal tissue includes emulsifying the portion
of corneal stromal tissue with an ultrasonic device. According to
some embodiments, the step of removing the portion of corneal
stromal tissue includes aspirating the emulsified tissue. According
to some embodiments, the step of removing the portion of corneal
tissue includes aspirating the portion of tissue through a corneal
incision. Some methods may include removing a natural crystalline
lens from the eye of the patient. Relatedly, some methods may
include replacing a natural crystalline lens of the eye of the
patient with an artificial intraocular lens implant.
[0019] In yet another aspect, embodiments of the present invention
encompass systems for altering refraction of an eye of a patient.
For example, systems may include a corneal deformation mechanism
configured to provide a first applanation shape configuration, and
a second applanation shape configuration different from the first
applanation shape configuration. Systems may also include a
photoalteration laser for transmitting a laser beam along an
optical path, a support for positioning the corneal deformation
mechanism along the optical path, and a processor for determining a
first laser target surface based on the first applanation shape
configuration and a second laser target surface based on the second
applanation shape configuration. Further, systems may include beam
scanning optics coupled to the processor for scanning the beam
along the first laser target surface when the eye assumes a first
intended biomechanical conformation responsive to engagement with
the first applanation shape configuration, and along the second
laser target surface when the eye assumes a second intended
biomechanical confirmation responsive to engagement with the second
applanation shape configuration. According to some embodiments, the
corneal deformation mechanism may include a material having an
index of refraction of about 1.377. In some instances, the corneal
deformation mechanism may include an applanation plate having a
substantially flat proximal portion for receiving the laser beam
from the photoalteration laser, and a distal portion configured to
engage an anterior corneal surface of the eye so as to induce the
first intended biomechanical conformation in the eye. The corneal
deformation mechanism may also include a lens deformation element
having a proximal portion configured to engage the distal portion
of the applanation plate, and a distal portion configured to engage
the anterior corneal surface of the eye so as to induce the second
intended biomechanical conformation in the eye. According to some
embodiments, the distal portion of the applanation plate includes a
substantially flat surface.
[0020] For a fuller understanding of the nature and advantages of
the present invention, reference should be had to the ensuing
detailed description taken in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a schematic perspective view of a laser-eye
surgery system and patient support system, according to embodiments
of the present invention.
[0022] FIG. 1A illustrates aspects of optical treatment systems and
methods according to embodiments of the present invention.
[0023] FIG. 1B illustrates aspects of optical treatment systems and
methods according to embodiments of the present invention.
[0024] FIG. 1C illustrates aspects of optical treatment systems and
methods according to embodiments of the present invention.
[0025] FIG. 1D illustrates aspects of optical treatment systems and
methods according to embodiments of the present invention.
[0026] FIG. 1E illustrates aspects of optical treatment systems and
methods according to embodiments of the present invention.
[0027] FIG. 1F illustrates aspects of optical treatment systems and
methods according to embodiments of the present invention.
[0028] FIG. 1G illustrates aspects of optical treatment systems and
methods according to embodiments of the present invention.
[0029] FIG. 1H illustrates aspects of optical treatment systems and
methods according to embodiments of the present invention.
[0030] FIG. 2 is a schematic illustration of a data processing
computer system for use in a laser eye surgery system, according to
embodiments of the present invention.
[0031] FIG. 3 illustrates a wavefront measurement system according
to an embodiment of the present invention.
[0032] FIG. 3A illustrates another wavefront measurement system
according to an embodiment of the present invention.
[0033] FIG. 4 is a schematic side view of a simplified model of an
eye and tissue-shaping surface and body, according to embodiments
of the present invention.
[0034] FIG. 5 is a schematic illustration of an image taken from
along the optical path through the image shaping body of FIG. 4,
showing horizontal and rotational alignment offsets between the
tissue shaping body and tissues of the eye, as maybe identified
using image processing software in the system of FIG. 1H, according
to embodiments of the present invention.
[0035] FIG. 6 schematically illustrates some of the optical and
structural components of the laser system of FIG. 1H, according to
embodiments of the present invention.
[0036] FIGS. 7A and 7B are top and side views, respectively, of a
laser delivery arm of the system of FIG. 1H, according to
embodiments of the present invention.
[0037] FIG. 8 depicts aspects of a treatment process according to
embodiments of the present invention.
[0038] FIG. 9 illustrates diagnostic, manufacturing, and treatment
aspects of exemplary methods according to embodiments of the
present invention.
[0039] FIGS. 10A and 10B depict aspects of a patient interface
according to embodiments of the present invention.
[0040] FIGS. 11A, 11B, and 11C depict aspects of surgical systems
according to embodiments of the present invention.
[0041] FIGS. 12A and 12B depict aspects of deformation mechanisms
according to embodiments of the present invention.
[0042] FIGS. 13A and 13B illustrate aspects of treatment processes
according to embodiments of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0043] Embodiments of the present invention generally provides
improved devices, systems, and methods for refractive correction of
an eye. Embodiments of the invention can take advantage of the
capabilities of femtosecond lasers, picosecond lasers and the like,
to incise the eye along precisely defined target surfaces. In some
instances, the volume of each individual laser ablation need not be
precisely known and/or controlled, particularly when the total
volume of tissue removal will be much greater than the overall
volumetric ablation. Even when the absolute depth of an individual
ablation or photoalteration is not perfectly controlled or known,
focused intrastromal laser ablation or photoalteration may be able
to incise the corneal tissue along a surface shape with sufficient
accuracy (such as by controlling the depths of ablation or
photoalteration spots along a target surface relative to each
other) so as to provide a desired high order resculpting or
reshaping of the overall cornea. By relying at least in part on
incising and mechanical removal of tissues along the incised tissue
surfaces (rather than solely or even primarily on volumetric
photoablation), precise corrections may be provided very
rapidly.
[0044] According to some embodiments, a femtosecond laser (or other
laser) of the optical system can be used to incise the cornea or to
cut a flap. A femtosecond laser may be used to make arcuate or
other incisions in the cornea, which incisions may be customized,
intrastromal, stable, predictable, and the like. Likewise, corneal
entry incisions may be made, which are custom, multi-plane, and
self sealing.
[0045] Many embodiments of the invention will make use of a
selected corneal tissue-shaping surface, with the surface often
being selected in response to a low-order, regular refractive error
of the eye, and/or a high-order refractive error of the eye. By
pre-shaping or conforming the tissue of the eye using a
tissue-shaping surface that substantially corresponds to a regular
and/or irregular refractive error of the eye, delivering
photoaltering energy to the eye to incise the cornea along a first
target surface, again conforming the tissue of the eye to that the
eye assumes a second different confirmation, delivering a second
photoaltering energy to the eye to incise the cornea along a second
different target surface, and removing a portion of corneal tissue
between the first and second target incisions, it is possible to
reshape the cornea of the eye.
[0046] Exemplary embodiments of the invention include techniques
for determining and manufacturing tissue-shaping bodies, with each
body of the set corresponding to a standard refractive error or
error range. By selecting or generating a body having an
appropriate shape, and by conforming the tissue of the eye to the
tissue shaping surface of that body, the capabilities of
intrastromal laser ablations for correction of a wide range of
regular and/or irregular refractive defects may be significantly
enhanced.
[0047] Embodiments of the present invention can be readily adapted
for use with existing laser systems and other optical treatment
devices. Although system, software, and method embodiments of the
present invention are described primarily in the context of a laser
eye surgery system, it should be understood that embodiments of the
present invention may be adapted for use optionally in combination
with alternative eye treatment procedures, systems, or modalities,
such as spectacle lenses, intraocular lenses, accommodating IOLs,
contact lenses, corneal ring implants, collagenous corneal tissue
thermal remodeling, corneal inlays, corneal onlays, other corneal
implants or grafts, and the like. Relatedly, systems, software, and
methods according to embodiments of the present invention are well
suited for customizing any of these treatment modalities to a
specific patient. Thus, for example, embodiments encompass custom
treatments which can be configured ameliorate any of a variety of
vision conditions in a particular patient based on their unique
ocular characteristics or anatomy.
[0048] Turning now to the drawings, FIG. 1 illustrates a laser eye
surgery system 10 of the present invention, including a laser 12
that produces a laser beam 14. Laser 12 is optically coupled to
laser delivery optics 16, which directs laser beam 14 to an eye E
of patient P. A delivery optics support structure (not shown here
for clarity) extends from a frame 18 supporting laser 12. A
microscope 20 is mounted on the delivery optics support structure,
the microscope often being used to image a cornea of eye E.
[0049] Laser 12 may comprises a femtosecond laser capable of
providing pulsed laser beams, which may be used in optical
procedures, such as localized photodisruption or photoalteration
(e.g., laser induced optical breakdown). Localized photodisruptions
or photoalterations can be placed at or below the surface of the
material to produce high-precision material processing. For
example, a micro-optics scanning system may be used to scan the
pulsed laser beam to produce an incision in the material, create a
flap of material, create a pocket within the material, form
removable structures of the material, and the like. The term "scan"
or "scanning" refers to the movement of the focal point of the
pulsed laser beam along a desired path or in a desired pattern.
[0050] To provide the pulsed laser beam, the laser 12 may utilize a
chirped pulse laser amplification system, such as described in U.S.
Pat. No. RE 37,585, for photoalteration. U.S. Pat. Publication No.
2004/0243111 also describes other methods of photoalteration. Other
devices or systems may be used to generate pulsed laser beams. For
example, non-ultraviolet (UV), ultrashort pulsed laser technology
can produce pulsed laser beams having pulse durations measured in
femtoseconds. Some of the non-UV, ultrashort pulsed laser
technology may be used in ophthalmic applications. For example,
U.S. Pat. No. 5,993,438 discloses a device for performing
ophthalmic surgical procedures to effect high-accuracy corrections
of optical aberrations. U.S. Pat. No. 5,993,438 discloses an
intrastromal photodisruption technique for reshaping the cornea
using a non-UV, ultrashort (e.g., femtosecond pulse duration),
pulsed laser beam that propagates through corneal tissue and is
focused at a point below the surface of the cornea to photodisrupt
stromal tissue at the focal point. Typically, photodisruption or
photoalteration involves the disruption or optical tissue, such as
corneal stroma or epithelium, ionization of molecules which is
induced by the laser. In some cases, a short duration, high
intensity laser is applied with low pulse energies, to form plasma
and tissue disruption or optical breakdown at the laser focal
point, often with minimal mechanical and thermal effects to nearby
tissue, thus providing a precise cutting mechanism.
[0051] The system 10 is capable of generating the pulsed laser beam
14 with physical characteristics similar to those of the laser
beams generated by a laser system disclosed in U.S. Pat. No.
4,764,930, U.S. Pat. No. 5,993,438, or the like. For example, the
system 10 can produce a non-UV, ultrashort pulsed laser beam for
use as an incising laser beam. This pulsed laser beam preferably
has laser pulses with durations as long as a few nanoseconds or as
short as a few femtoseconds. For intrastromal photodisruption of
the tissue, the pulsed laser beam 14 has a wavelength that permits
the pulsed laser beam 14 to pass through the cornea without
absorption by the corneal tissue. The wavelength of the pulsed
laser beam 14 is generally in the range of about 3 microns to about
1.9 nm, preferably between about 400 nm to about 3000 nm, and the
irradiance of the pulsed laser beam 14 for accomplishing
photodisruption of stromal tissues at the focal point is greater
than the threshold for optical breakdown of the tissue. Although a
non-UV, ultrashort pulsed laser beam is described in this
embodiment, the laser 12 produces a laser beam with other pulse
durations and different wavelengths in other embodiments.
[0052] In this embodiment, the delivery optics 16 direct the pulsed
laser beam 14 toward the eye (e.g., onto the cornea) for plasma
mediated (e.g., non-UV) photoablation of superficial tissue, or
into the stroma for intrastromal photodisruption of tissue. The
system 10 may also include an applanation lens (not shown) to
flatten the cornea prior to scanning the pulsed laser beam 14
toward the eye. A curved, or non-planar, lens may substitute this
applanation lens to contact the cornea in other embodiments.
[0053] Laser system 10 will generally include a computer or
programmable processor 22. Processor 22 may comprise (or interface
with) a conventional PC system including the standard user
interface devices such as a keyboard, a display monitor, and the
like. Processor 22 will typically include an input device such as a
magnetic or optical disk drive, an internet connection, or the
like. Such input devices will often be used to download a computer
executable code from a tangible storage media 29 embodying any of
the methods of the present invention. Tangible storage media 29 may
take the form of a floppy disk, an optical disk, a data tape, a
volatile or non-volatile memory, RAM, or the like, and the
processor 22 will include the memory boards and other standard
components of modern computer systems for storing and executing
this code. Tangible storage media 29 may optionally embody
wavefront sensor data, wavefront gradients, a wavefront elevation
map, a treatment map, a corneal elevation map, and/or an ablation
table. While tangible storage media 29 will often be used directly
in cooperation with a input device of processor 22, the storage
media may also be remotely operatively coupled with processor by
means of network connections such as the internet, and by wireless
methods such as infrared, Bluetooth, or the like.
[0054] Laser 12 and delivery optics 16 will generally direct laser
beam 14 to the eye of patient P under the direction of a computer
22. Computer 22 will often selectively adjust laser beam 14 to
expose portions of the cornea to the pulses of laser energy so as
to effect a predetermined sculpting of the cornea and alter the
refractive characteristics of the eye. In many embodiments, both
laser beam 14 and the laser delivery optical system 16 will be
under computer control of processor 22 to effect the desired laser
incising or sculpting process, with the processor effecting (and
optionally modifying) the pattern of laser pulses. The pattern of
pulses may by summarized in machine readable data of tangible
storage media 29 in the form of a treatment table, and the
treatment table may be adjusted according to feedback input into
processor 22 from an automated image analysis system in response to
feedback data provided from an ablation monitoring system feedback
system. Optionally, the feedback may be manually entered into the
processor by a system operator. Such feedback might be provided by
integrating the wavefront measurement system described below with
the laser treatment system 10, and processor 22 may continue and/or
terminate a sculpting treatment in response to the feedback, and
may optionally also modify the planned sculpting based at least in
part on the feedback. Measurement systems are further described in
U.S. Pat. No. 6,315,413, the full disclosure of which is
incorporated herein by reference.
[0055] Laser beam 14 may be adjusted to produce the desired
incisions or sculpting using a variety of alternative mechanisms.
The laser beam may also be tailored by varying the size and offset
of the laser spot from an axis of the eye, as described in U.S.
Pat. Nos. 5,683,379, 6,203,539, and 6,331,177, the full disclosures
of which are incorporated herein by reference. In some cases, the
laser beam 14 may be selectively limited using one or more variable
apertures. An exemplary variable aperture system having a variable
iris and a variable width slit is described in U.S. Pat. No.
5,713,892, the full disclosure of which is incorporated herein by
reference.
[0056] Still further alternatives are possible, including scanning
of the laser beam over the surface of the eye and controlling the
number of pulses and/or dwell time at each location, as described,
for example, by U.S. Pat. No. 4,665,913, the full disclosure of
which is incorporated herein by reference; using masks in the
optical path of laser beam 14 which ablate to vary the profile of
the beam incident on the cornea, as described in U.S. Pat. No.
5,807,379, the full disclosure of which is incorporated herein by
reference; hybrid profile-scanning systems in which a variable size
beam (typically controlled by a variable width slit and/or variable
diameter iris diaphragm) is scanned across the cornea; or the like.
The computer programs and control methodology for these laser
pattern tailoring techniques are well described in the patent
literature.
[0057] Additional components and subsystems may be included with
laser system 10, as should be understood by those of skill in the
art. Further details of suitable systems can be found in commonly
assigned U.S. Publication Nos. 20090247997 and 20090247998, the
complete disclosures of which are incorporated herein by reference.
Suitable systems also include commercially available femtosecond
laser systems such as those manufactured and/or sold by Alcon,
Technolas, Nidek, WaveLight, Schwind, Zeiss-Meditec, Ziemer, and
the like. According to some embodiments, spatial and/or temporal
integrators may be included to control the distribution of energy
within the laser beam, as described in U.S. Pat. No. 5,646,791, the
full disclosure of which is incorporated herein by reference.
Ablation effluent evacuators/filters, aspirators, and other
ancillary components of the laser surgery system are known in the
art. Basis data can be further characterized for particular lasers
or operating conditions, by taking into account localized
environmental variables such as temperature, humidity, airflow, and
aspiration. Further details of suitable systems for performing a
laser ablation procedure can be found in commonly assigned U.S.
Pat. Nos. 4,665,913, 4,669,466, 4,732,148, 4,770,172, 4,773,414,
5,207,668, 5,108,388, 5,219,343, 5,646,791 and 5,163,934, the
complete disclosures of which are incorporated herein by
reference.
[0058] The delivery optics 16 may include a scanner that operates
at pulse repetition rates between about 10 kHz and about 400 kHz,
or at any other desired rate. In one embodiment, the scanner
generally moves the focal point of the pulsed laser beam 14 through
the desired scan pattern at a substantially constant scan rate
while maintaining a substantially constant separation between
adjacent focal points of the pulsed laser beam 14. The step rate at
which the focal point of the laser beam 14 is moved is referred to
herein as the scan rate. The scan rates may be selected from a
range between about 30 MHz and about 1 GHz with a pulse width in a
range between about 300 picoseconds and about 10 femtoseconds,
although other scan rates and pulse widths may be used. Further
details of laser scanners are known in the art, such as described,
for example, in U.S. Pat. No. 5,549,632, the entire disclosure of
which is incorporated herein by reference.
[0059] In one embodiment, the scanner utilizes a pair of scanning
mirrors or other optics (not shown) to angularly deflect and scan
the pulsed laser beam 14. For example, scanning mirrors driven by
galvanometers may be employed where each of the mirrors scans the
pulsed laser beam 14 along one of two orthogonal axes. A focusing
objective (not shown), whether one lens or several lenses, images
the pulsed laser beam 14 onto a focal plane of the system 10. The
focal point of the pulsed laser beam 14 may thus be scanned in two
dimensions (e.g., the x-axis and the y-axis) within the focal plane
of the system 10. Scanning along the third dimension, i.e., moving
the focal plane along an optical axis (e.g., the z-axis), may be
achieved by moving the focusing objective, or one or more lenses
within the focusing objective, along the optical axis.]
[0060] FIG. 1A shows a corneal deformation mechanism 100a and a
patient cornea 110a having an anterior surface 120a. As shown here,
deformation mechanism 100a can be advanced toward anterior surface
120a, in a direction as indicated by arrow A. In a method of
providing a surgical treatment to the eye of the patient, the
corneal deformation mechanism 100a can be positioned against the
anterior surface 120a of the eye of the patient, so as to induce a
first biomechanical conformation within a corneal stromal tissue of
the eye, as depicted in FIG. 1B. For example, as shown here, the
corneal deformation mechanism 100a impinges upon the anterior
surface 120a, so as to flatten or reshape the anterior surface,
thus deforming the corneal tissue 110a. Photoaltering energy, as
indicated by arrow PE, can be delivered to the eye while the
corneal stromal tissue 110a is in a first biomechanical
conformation (e.g. in response to the applied deformation mechanism
100a), so as to incise the corneal stromal tissue along a first
target surface 130a. In this way, a steady and exacting fluence can
be scanned in the x-y plane within the corneal stroma. As shown
here, the photoaltering energy can form a beam waist, focal point,
or altering focus F, which when scanned through the corneal tissue,
for example as part of a first photoaltering energy protocol,
creates an incision within the corneal tissue 110a along target
surface 130a. The location or position of the focal point within
the corneal stroma is governed by the applanated lens. In this way,
the focal depth of the photoalteration within the eye is due to the
external applanated lens which creates a deformation in the cornea,
or otherwise imposes a desired biomechanical shape on the eye. As
shown here, focus F can be scanned approximately parallel to a flat
portion of the deformed flat anterior corneal surface 120a, in a
way that the z axis depth of the focal point does not vary as the
focus is scanned in the x-y plane. In addition to providing a
photoalteration along a flat surface, embodiments of the present
invention also encompass techniques for incising the eye along
other types of predetermined paths, including surfaces with a
consistent curvature, and the like.
[0061] As indicated in FIG. 1C, the corneal deformation mechanism
100a impinges upon the anterior corneal surface, so as to reshape
the anterior surface and induce a second biomechanical conformation
in the eye. In some cases, the corneal deformation mechanism 100a
may be provided as an applanation assembly, which may include, for
example, a first deformation element 102a (e.g. an applanation
plate) and a second deformation element 104a (e.g. a lens). The
corneal deformation mechanism 100a can be positioned against the
anterior surface 120a of the eye of the patient, such that the
corneal stromal tissue 110a of the eye assumes a second
biomechanical conformation different from the first biomechanical
conformation. As shown here, first incision 130a, which was a
substantially flat incision in the conformation of FIG. 1B, has now
become a curved incision in FIG. 1C. Photoaltering energy can be
applied to the eye according to a second photoaltering energy
protocol when the eye is in the second biomechanical conformation
of FIG. 1C, so as to incise the corneal stromal tissue 110a along a
second target surface 140a which is different from the first target
surface 130a. Effectively, the presence of deformation element 104a
operates to alter the depth of the focus of the femtosecond laser
relative to the anterior corneal surface, by deforming the corneal
tissue while at the same time not refracting the laser energy. In
this way, a portion or volume 150a of corneal stromal tissue is
defined between the first target surface 130a and the second target
surface 140a. Again, formation of the second target surface 140a
can be accomplished using a steady and exacting fluence of the
laser, scanned in the x-y plane within the corneal stroma, in a way
such that the z axis depth of the focal point does not vary during
the scan.
[0062] The focal depth of the photoalteration within the eye is due
to the external applanated lens which creates a deformation or
biomechanical reshaping of the cornea, or otherwise imposes a
desired biomechanical shape on the eye. In a first shape
configuration (e.g. as depicted in FIG. 1B), the applanation
assembly or deformation mechanism has a first pre-determined or
known shape that is intended to induce a first biomechanical
conformation within the corneal stromal tissue. In a second shape
configuration (e.g. as depicted in FIG. 1C), the applanation
assembly or deformation mechanism has a second pre-determined or
known shape that is intended to induce a second biomechanical
conformation within the corneal stromal tissue.
[0063] Embodiments of the present invention encompass systems and
methods that involve the formation of a posteriorly disposed
photoalteration or cut (e.g. incision along first target surface
130a) prior to the formation of an anteriorly disposed
photoalteration or cut (e.g. incision along second target surface
140a), such as when the applanation plate is used in a first
photoalteration step and the combined applanation plate and lens
are used in a second photoalteration step following the first
photoalteration step. Likewise, embodiments of the present
invention similarly encompass systems and methods that involve the
formation of an anteriorly disposed photoalteration or cut (e.g.
incision along second target surface 140a) prior to the formation
of a posteriorly disposed photoalteration or cut (e.g. incision
along first target surface 130a), such as when the combined
applanation plate and lens are used in a first photoalteration step
and the applanation plate is used in a second photoalteration step
following the first photoalteration step.
[0064] As depicted in FIG. 1D, methods may also include removing
the portion 150a of corneal stromal tissue (e.g. a lenticule) that
is bound by or disposed between the first and second target
surfaces 130a, 140a. In some cases, the corneal tissue portion or
lentoid volume 150a is removed via a suction tube. In some cases,
the tissue portion, which may in some cases include both epithelium
and stroma, may be removed mechanically from the eye using other
techniques, such as by grasping the tissue with micro forceps,
displacing the tissue using a flow of fluid (either liquid or gas),
grasping the tissue using a vacuum applied through a port in a
deformation element or a hand-held implement, or the like. When the
tissue portion 150a is removed, the shape of the resulting space
between the first and second target surfaces approximates that of
the second deformation element 104a. In this way, the shape of the
deformation element or pre-formed lens can be approximated or
mimicked as a corresponding cavity within the stroma. In some
cases, the applanated element 104a is a customized shape, designed
specifically to treat a particular vision condition of the
patient.
[0065] As illustrated in FIG. 1E, following removal of portion
150a, the first and second target surfaces 130a and 140a can then
appose one another to close the space therebetween, for example by
the corneal stroma collapsing upon itself, and as such the corneal
tissue 110a adopts an altered or corrected shape or configuration,
relative to the original shape or configuration shown in FIG. 1A.
The altered or corrected eye shape is thus informed by the original
eye shape as well as the deformation lens shape. According to some
embodiments, the effect of the volumetric removal can be
approximated, predicted, or simulated by providing the patient with
a contact lens having a shape which corresponds to the shape of the
deformation lens.
[0066] Removal of this tissue can effect both high-order or
irregular refractive correction and low-order or regular refractive
correction of the eye. Appropriate tissue removal shapes may be
determined using ray tracing or wavefront analysis, through
empirical studies, and the like, and may in some cases reflect the
anticipated epithelial regrowth from an incision formed along a
target laser surface. The incision need not be complete when a
deformation mechanism is retracted, as small remaining contact
points can optionally be separated by pulling of the severed tissue
body. In some cases, the tissue targeted for removal may extend to
an exposed tissue region engaged by the deformation mechanism, and
a vacuum port of the deformation mechanism may be used to remove
the tissue bordered by the incisions when the deformation mechanism
is withdrawn proximally away from eye. Additional ports in the
deformation mechanism (or an adjacent structure of the system) may
provide fluid or gas flow to help separate the corneal tissues from
the tissue-shaping surfaces and the like, to apply a vacuum to
affix the engaged eye relative to the delivery optics, and the
like. In some cases, deformation mechanism may include multiple
tissue-shaping surfaces, such as a first tissue-shaping surface
corresponding to a first selected shape, a second selected shape,
and so on. Switching between the tissue-shaping surfaces may be
implemented using the motion stages of a support structure.
[0067] Techniques developed to facilitate formation of a LASIK
flap, including the formation of ablation reservoirs, applanation
lens support and vacuum tissue affixation systems, alternating
locations along the target surface to inhibit thermal damage, and
the like, may be modified for use in laser incising of the corneal
tissues along the target surface. Hence, as depicted in FIG. 1E,
following removal of the lenticule or tissue portion, the tissues
bordered by the laser target surfaces 130a and 140a can engage and
attach to each other. Once again, the final corneal surface will
reflect any regular and/or irregular or high-order aberration
corrected provided by the deformation mechanism, but without here
having to wait for epithelial regrowth to enjoy the benefits of the
procedure. However, in contrast to standard LASIK procedures which
involve the formation of such a hinged flap (e.g. partial
microkeratome cut which is pulled back to expose the corneal bed,
followed by volumetric ablation with an excimer laser, and
replacement of the flap), embodiments of the present invention
provide for the removal of a portion of the corneal stroma, without
requiring creation of the hinged flap.
[0068] According to some embodiments, a method of providing a
surgical treatment to an eye of a patient may include delivering a
first photoaltering energy protocol through a first configuration
laser transmitting assembly 100a, and into corneal stromal tissue
110a of the eye, so as to incise the corneal stromal tissue along a
first target surface 130a, as shown in FIG. 1B. The first
configuration laser transmitting assembly determines a first focal
depth pattern (relative to the anterior corneal surface) for the
delivered energy along the first target surface 130a. The method
also includes delivering a second photoaltering energy protocol
through a second configuration laser transmitting assembly 102a,
104a, and into corneal stromal tissue 110a of the eye, so as to
incise the corneal stromal tissue along a second target surface
140a, as shown in FIG. 1C. The second configuration laser
transmission assembly determines a second focal depth pattern
(relative to the anterior corneal surface) for the delivered energy
along the second target surface 140a. As depicted in FIG. 1D, the
first target surface 130a corresponds to a first focal depth
pattern (relative to the anterior corneal surface) and the second
target surface 140a corresponds to a second focal depth pattern
(relative to the anterior corneal surface). The difference between
the first and second focal depth patterns corresponds to a
resulting of portion of corneal stromal tissue disposed between the
first and second target surfaces, which can be removed.
[0069] According to some embodiments, a method of providing a
surgical treatment to an eye of a patient may include providing a
first configuration energy transmitting assembly 100a along a beam
path between an energy source and an anterior surface of the eye of
the patient, and delivering a first photoaltering energy protocol
along the beam path from the energy source, through the first
configuration energy transmitting assembly, and into corneal
stromal tissue 110a of the eye, so as to incise the corneal stromal
tissue along a first target surface 130a, as shown in FIG. 1B. The
first configuration energy transmitting assembly determines a first
focal depth pattern (relative to the anterior corneal surface) for
the delivered energy along the first target surface 130a. The
method may also include delivering a second photoaltering energy
protocol along the beam path from the energy source, through a
second configuration energy transmitting assembly 102a, 104a, and
into corneal stromal tissue 110a of the eye, so as to incise the
corneal stromal tissue along a second target surface 140a, as
depicted in FIG. 1C. The second configuration energy transmitting
assembly determines a second focal depth pattern (relative to the
anterior corneal surface) for the delivered energy along the second
target surface 140a. As depicted in FIG. 1D, the first target
surface 130a corresponds to a first focal depth pattern (relative
to the anterior corneal surface) and the second target surface 140a
corresponds to a second focal depth pattern (relative to the
anterior corneal surface). The difference between the first and
second focal depth patterns corresponds to a resulting of portion
of corneal stromal tissue disposed between the first and second
target surfaces, which can be removed.
[0070] Hence, embodiments of the present invention encompass
systems and methods for providing a patient with an ocular
treatment. Exemplary embodiments encompass techniques where the
cornea is applanated and a laser light focal waist from a
femtosecond laser beam is scanned laterally within eye in order to
create a first incision, the cornea is further applanated, this
time by including an inserted or auxiliary lens, and a femtosecond
beam waist is used to create a second incision, such that the first
and second cuts define a volumetric lenticule that can be removed,
for example via suction through a needle, thus providing a reshaped
cornea. According to some embodiments, the epithelium remains
intact during the procedure. In this way, it is possible to remove
a volume of corneal stromal tissue, without using complicated
control mechanism to vary the z-axis depth of the beam focal point.
Instead, the focal point of the beam is simply scanned across a
flat or smooth surface when making both the first and the second
cuts. In other words, two regular flap-type cuts can be made, where
the first cut is made without the lens (e.g. a pre-cut IOL-like
body), and the second cut is made using the lens. The volume of
tissue removed is often determined by the shape of the lens or
deformation mechanism used. Hence, that lens can be formed based on
measured refractive properties of the eye, and the lens shape also
corresponds to the refractive correction intended for the eye.
Because the lens shape is being used to deform the cornea in a
corresponding shape, and not necessarily to bend light, the lens
material will often have a refractive index similar to that of the
corneal stroma (e.g. 1.377). In some cases, material used in the
fabrication of the lens can be selected so as to provide a
consistent index of refraction between the lens, or interface lens
system, and the eye.
[0071] According to some embodiments, a single cut extending
through the epithelium can be made, when using the deformation
mechanism or lens to deform the eye. In this way, the depth of the
incision relative to the anterior surface of the cornea can be
altered based on the shape of the deformation mechanism or lens.
Because this technique can remove an amount of corneal surface
epithelium, the procedure may involve a longer recovery time due to
corneal healing or re-epithelialization.
[0072] According to some embodiments, a shaped lens can be used to
adjust the depth of the beam waist relative to the anterior corneal
surface. In some cases, however, the shaped lens may not be
contacted with the cornea. Instead, the lens may operate to adjust
the depth of the beam waist within the cornea, according to the
lens shape.
[0073] In some instances, an applanation assembly can transition
between a first shape configuration and a second shape
configuration. For example, as shown in FIG. 1F, applanation
assembly 100f can modulate or change between a first shape
configuration 110f and a second shape configuration 120f When in
the first shape configuration 110f, the applanation assembly 100f
is shaped to induce a first biomechanical conformation within
corneal stromal tissue when impinging or pressed thereupon (e.g.
when a corneal contacting surface 102f of the assembly 100f is
placed against the anterior corneal surface of the eye), and when
in the second shape configuration 120f, the applanation assembly
100f is shaped to induce a second biomechanical conformation within
corneal stromal tissue when impinging or pressed thereupon (e.g.
when a corneal contacting surface 102f of the assembly 100f is
placed against the anterior corneal surface of the eye).
[0074] As shown in FIG. 1G, in some cases a corneal deformation
mechanism 100g may include an applanation plate 110g and a
removable body 120g. The removable body 120g may be attached to or
detached from the applanation plate 110g. In some embodiments, the
removable body 120g can be constructed of a material having an
index of refraction of about 1.377. In some instances, deformation
mechanism 100g may be used in a dual mode procedure. For example,
in a first mode, the removable body 120g can be removed from the
applanation plate 110g during one step (e.g. where the applanation
plate 110g is positioned against the cornea, and photoalteration
energy is delivered therethrough to the corneal tissue to form an
incision) such that photoalteration energy passes through only the
applanation plate 110g before photoaltering the eye. In a second
mode, the removable body 120g can be coupled with the applanation
plate 110g during another step (e.g. where the removable body 120g
is positioned against the cornea, and photoalteration energy is
delivered through both the applanation plate 110g and the removable
body 120g to the corneal tissue to form an incision) such that
photoalteration energy passes through the combined plate 110g and
body 120g before photoaltering the eye.
[0075] Referring now to FIG. 1H, an exemplary system 100 is
suitable for correcting regular and/or irregular refractive errors
of eye E. System 100 generally directs laser energy from a
femtosecond laser 102 to corneal tissues of eye E while those
tissues are shaped by a deformation mechanism 104. In some cases,
deformation mechanism 104 is supported and positioned by an
electromechanical support structure 106, with the exemplary support
structure having a series of motion stages for selectively
positioning the deformation mechanism relative to the tissues of
eye E. Optics 108 of system 100 selectively direct the laser energy
from laser 102 into the corneal tissues, with the optics and
support structure generally being under the control of a system
processor or computer 22.
[0076] The deformation mechanism 104 generally includes at least
one distal tissue-shaping surface 112. According to some
embodiments, the target laser surface will, for example, be
nominally planar, and the tissue-shaping surface may present a
similarly nominally planar surface, or a shaped or curved surface.
In an exemplary embodiment, a deformation mechanism may include a
flat (or optionally curved or lens-shaped) proximal surface. The
material along surface 112 (and typically from surface 112 to the
proximal surface) comprises a material which is sufficiently
transmissive of the laser energy from laser 102 to allow treatment
eye E without overheating of the deformation mechanism, the
tissue-shaping surface, and the engaged corneal tissues. Suitable
materials may comprise, for example, glass, a suitable polymer such
as PMMA, or the like. Deformation mechanism 104 may also include
positioning surfaces that can be engaged by corresponding surfaces
of the support structure 106 so as to accurately position the
deformation mechanism horizontally (along the X-Y plane) relative
to an optical axis 116 of the laser treatment, and also so as to
rotationally position the deformation mechanism 104 about the axis
116 (such as the notch illustrated). This can help facilitate
rotational alignment of any aspect of a tissue-shaping surface 112
relative to the eye E. A wide variety of alternative deformation
mechanisms might also be implemented.
[0077] Referring now to FIG. 1H, elements of system 100 may be
incorporated into, and/or may make use of components of a laser eye
surgery system 10. Laser eye surgery system 10 generally includes a
laser system 12 and a patient support system 15. Laser system 12
includes a housing that contains both a laser and a system
processor 22. The laser generates the laser beam 14, which is
directed to a patient's eye under the direction of a system
operator. Delivery optics used to direct the laser beam, the
microscope mounted to the delivery optics, and the like may employ
existing structures from commercially available laser systems,
including at least some portions of femtosecond or excimer
refractive laser systems, such as those available from ADVANCED
MEDICAL OPTICS, INC. of Santa Clara, Calif.
[0078] In addition to (or in some cases, instead of) adjustment to
the delivery optics directing laser beam 14, alignment between the
patient and the laser treatment system may be provided at least in
part by the patient support system 15. Patient support system 15
generally includes a patient support 21 having an associated
patient support movement mechanism. Patient support 21 may be
contoured, helping to position the patient at a nominal location on
the patient support. Large and fine adjustments of the patient
support and patient may be effected using large and fine motion
control mechanisms such as those more fully described in U.S.
patent application Ser. No. 10/226,867 filed on Aug. 20, 2002
(Attorney Docket No. 018158-012730US), the disclosure of which is
incorporated herein by reference.
[0079] FIG. 2 is a simplified block diagram of an exemplary
computer system 22 that may be used by the laser surgical system
100. Computer system 22 typically includes at least one processor
52 which may communicate with a number of peripheral devices
(and/or other processors) via a bus subsystem 54. These peripheral
devices may include a storage subsystem 56, typically including a
memory 58 and a file storage subsystem 60. The peripheral devices
may also include one or more user interface input device 62, user
interface output device 64, and a network interface subsystem 66.
Network interface subsystem 66 can provide an interface to outside
networks 68 and/or other devices, such as the wavefront measurement
system 30 described below with reference to FIG. 3 or 3A.
[0080] User interface input devices 62 may include a keyboard,
pointing devices such as a mouse, trackball, touch pad, or graphics
tablet, a scanner, foot pedals, a joystick, a touch screen
incorporated into the display, audio input devices such as voice
recognition systems, microphones, and other types of input devices.
User input devices 62 will often be used to download a computer
executable code from a tangible storage media 29 embodying any of
the methods described herein. In general, use of the term "input
device" is intended to include a variety of conventional and
proprietary devices and ways to input information into computer
system 22.
[0081] User or user interface output devices 64 may include a
display subsystem, a printer, a fax machine, or non-visual displays
such as audio output devices. The display subsystem may comprise a
cathode ray tube (CRT), a flat-panel display such as a liquid
crystal display (LCD), a projection device, or the like. The
display subsystem may also provide a non-visual display such as via
audio output devices. In general, use of the term "output device"
is intended to include a variety of conventional and proprietary
devices and ways to output information from computer system 22 to a
user.
[0082] Storage subsystem 56 stores the basic programming and data
constructs that provide the functionality of the various
embodiments of the invention. For example, a database and modules
implementing the functionality of the methods described herein may
be stored in storage subsystem 56. These software modules will
generally be executed by processor 52. In a distributed processing
environment, the software modules may be stored on any of a
plurality of computer systems and executed by processors of those
computer subsystems. Storage subsystem 56 typically comprises
memory subsystem 58 and file storage subsystem 60.
[0083] Memory subsystem 58 typically includes a number of memories
including a main random access memory (RAM) 70 for storage of
instructions and data during program execution, and a read only
memory (ROM) 72 in which fixed instructions are stored. File
storage subsystem 60 may provide persistent (non-volatile) storage
for program and data files, and may include tangible storage media
29 (see e.g. FIGS. 1, 1H, and 3) which may optionally embody
wavefront sensor data, wavefront gradients, a wavefront elevation
map, a treatment map, and/or an ablation table, as well as machine
readable code or programming instructions for implementing the data
processing and control methods described herein. File storage
subsystem 60 may include a hard disk drive, a floppy disk drive
(along with associated removable media), a compact digital read
only memory (CD-ROM) drive, an optical drive, DVD, CD-R, CD-RW,
solid-state removable memory, and/or other removable media
cartridges or disks. One or more of the drives may be located at
remote locations or on other connected computers at other sites
coupled to computer system 22. The modules implementing the
functionality of embodiments of the present invention may be stored
by file storage subsystem 60.
[0084] Bus subsystem 54 provides a mechanism for letting the
various components and subsystems of computer system 22 communicate
with each other as intended. The various subsystems and components
of computer system 22 need not be at the same physical location but
may be distributed at various locations within a distributed
network. Although a single bus subsystem is shown schematically,
alternate embodiments the bus may utilize multiple bus systems or
multiple busses.
[0085] Computer system 22 can be of various types including a
personal computer, a portable computer, a work station, a computer
terminal, a network computer, a control system in a wavefront
measurement system or laser surgical system, a mainframe, or
another appropriate data processing system. As computers and
networks change over time, the description of computer system 22
shown in FIG. 2 represents only an example for purposes of
illustration of an embodiment of the invention, and many other
configurations of computer systems are possible, for example system
configurations having more or less components than the computer
system depicted in FIG. 2.
[0086] As noted above, laser system 100 may correct both regular
and irregular optical errors of the eye. Regular optical errors
(such as spherical errors associated with myopia and hyperopia, and
cylindrical errors associated with standard cylindrical stigmatism)
can be measured using any of a wide variety of commercially
available diagnostic devices, including phoropters, automated
refractometers, trial lenses, and the like. While a variety of
devices and systems have also been developed and to measure
irregular optical errors of the eye (including topographers,
tomography systems, and the like) any irregular astigmatism or
high-order aberrations of the eye will often be measured using a
wavefront system.
[0087] Referring now to FIG. 3, one embodiment of a wavefront
measurement system 30 is schematically illustrated in simplified
form. In very general terms, wavefront measurement system 30 is
configured to sense local slopes of a wavefront exiting the
patient's eye. Devices based on the Hartmann-Shack principle
generally include a lenslet array to sample the slopes across the
pupil of the eye. In some embodiments, lenslet arrays may be used
to sample the gradient map uniformly over an aperture, which is
typically the exit pupil of the eye. Thereafter, the local slopes,
for example of the gradient map, are analyzed so as to reconstruct
the wavefront surface or map, often using Zernike polynomial
expansion methods.
[0088] More specifically, one wavefront measurement system 30
includes a light or image source 32, such as a laser, which
projects a source image through optical or refractive tissues 34 of
eye E so as to form an image 44 upon a surface of retina R. The
image from retina R is transmitted by the optical or refractive
system of the eye (e.g., optical or refractive tissues 34) and
imaged onto a wavefront sensor 36 by system optics 37. The
wavefront sensor 36 communicates signals to a computer system 22'
for measurement of the optical errors in the optical tissues 34
and/or determination of an optical tissue ablation treatment
program. Computer 22' may include the same or similar hardware as
the computer system 22 illustrated in FIGS. 1, 1H, and 2. Computer
system 22' may be in communication with computer system 22 that
directs the laser surgery system 10, or some or all of the computer
system components of the wavefront measurement system 30 and laser
surgery system 10 may be combined or separate. If desired, data
from wavefront sensor 36 may be transmitted to a laser computer
system 22 via tangible media 29, via an I/O port, via a networking
connection 66 such as an intranet or the Internet, or the like.
[0089] Wavefront sensor 36 generally comprises a lenslet array 38
and an image sensor 40. The reflected light from retina R is
transmitted through optical tissues 34 and imaged onto a surface of
image sensor 40 and the eye pupil P is similarly imaged onto a
surface of lenslet array 38. The lenslet array separates the
transmitted light beam into an array of beamlets 42, and (in
combination with other optical components of the system) images the
separated beamlets on the surface of sensor 40. Sensor 40 typically
comprises a charged couple device or "CCD," and senses the
characteristics of these individual beamlets, which can be used to
determine the characteristics of an associated region of optical
tissues 34. In particular, where image 44 comprises a point or
small spot of light, a location of the transmitted spot as imaged
by a beamlet can directly indicate a local gradient of the
associated region of optical tissue.
[0090] Eye E generally defines an anterior orientation ANT and a
posterior orientation POS. Image or light source 32 generally sends
light in a posterior orientation through optical tissues 34 onto
retina R as indicated in FIG. 3. Optical tissues 34 again transmit
light or image 44 reflected from the retina anteriorly toward
wavefront sensor 36. Image 44 actually formed on retina R may be
distorted by any imperfections in the eye's optical system when the
image source is originally transmitted by optical tissues 34.
Optionally, image projection optics 46 may be configured or adapted
to decrease any distortion of image 44.
[0091] In some embodiments, projection optics or image source
optics 46 may decrease lower order optical errors by compensating
for spherical and/or cylindrical errors of optical tissues 34.
Higher order optical errors of the optical tissues may also be
compensated through the use of an adaptive optics system, such as a
deformable mirror. Use of a light source or image source 32
selected to define a point or small spot at image 44 upon retina R
may facilitate the analysis of the data provided by wavefront
sensor 36. Distortion of image 44 may be limited by transmitting a
source image through a central region 48 of optical tissues 34
which is smaller than a pupil 50, as the central portion of the
pupil may be less prone to optical errors than the peripheral
portion. Regardless of the particular light source structure, it
will be generally be beneficial to have a well-defined and
accurately formed image 44 on retina R.
[0092] According to some embodiments, wavefront data may be stored
in computer readable medium 29 or a memory of the wavefront sensor
system 30 in two separate arrays containing the x and y wavefront
gradient values obtained from image spot analysis of the
Hartmann-Shack sensor images, plus the x and y pupil center offsets
from the nominal center of the Hartmann-Shack lenslet array, as
measured by the pupil camera 51 (FIG. 3) image. Such information
may include the available information on the wavefront error of the
eye and is typically sufficient to reconstruct the wavefront or a
desired portion of it. In such embodiments, there may be no need to
reprocess the Hartmann-Shack image more than once, and the data
space required to store the gradient array is not large. For
example, to accommodate an image of a pupil with an 8 mm diameter,
an array of a 20.times.20 size (i.e., 400 elements) is often
sufficient. As can be appreciated, in other embodiments, the
wavefront data may be stored in a memory of the wavefront sensor
system in a single array or multiple arrays.
[0093] While embodiments of the invention will generally be
described with reference to sensing of an image 44, it should be
understood that a series of wavefront sensor data readings may be
taken. For example, a time series of wavefront data readings may
help to provide a more accurate overall determination of the ocular
tissue aberrations. As the ocular tissues can vary in shape over a
brief period of time, a plurality of temporally separated wavefront
sensor measurements can avoid relying on a single snapshot of the
optical characteristics as the basis for a refractive correcting
procedure. Still further alternatives are also available, including
taking wavefront sensor data of the eye with the eye in differing
configurations, positions, and/or orientations. For example, a
patient will often help maintain alignment of the eye with
wavefront measurement system 30 by focusing on a fixation target,
as described in U.S. Pat. No. 6,004,313, the full disclosure of
which is incorporated herein by reference. By varying a position of
the fixation target as described in that reference, optical
characteristics of the eye may be determined while the eye
accommodates or adapts to image a field of view at a varying
distance and/or angles.
[0094] The location of the optical axis of the eye may be verified
by reference to the data provided from a pupil camera 52. In the
exemplary embodiment, a pupil camera 52 images pupil 50 so as to
determine a position of the pupil for registration of the wavefront
sensor data relative to the optical tissues.
[0095] An alternative embodiment of a wavefront measurement system
is illustrated in FIG. 3A. The major components of the system of
FIG. 3A are similar to those of FIG. 3. Additionally, FIG. 3A
includes an adaptive optical element 53 in the form of a deformable
mirror. The source image is reflected from deformable mirror 98
during transmission to retina R, and the deformable mirror is also
along the optical path used to form the transmitted image between
retina R and imaging sensor 40. Deformable mirror 98 can be
controllably deformed by computer system 22 to limit distortion of
the image formed on the retina or of subsequent images formed of
the images formed on the retina, and may enhance the accuracy of
the resultant wavefront data. The structure and use of the system
of FIG. 3A are more fully described in U.S. Pat. No. 6,095,651, the
full disclosure of which is incorporated herein by reference.
[0096] The components of an embodiment of a wavefront measurement
system for measuring the eye and ablations may comprise elements of
a WaveScan.RTM. system, available from AMO MANUFACTURING USA, LLC,
Milpitas, Calif. One embodiment includes a WaveScan system with a
deformable mirror as described above. An alternate embodiment of a
wavefront measuring system is described in U.S. Pat. No. 6,271,915,
the full disclosure of which is incorporated herein by reference.
It is appreciated that any wavefront aberrometer could be employed
for use with the present invention. Relatedly, embodiments of the
present invention encompass the implementation of any of a variety
of optical instruments provided by AMO WAVEFRONT SCIENCES, LLC,
including the COAS wavefront aberrometer, the ClearWave contact
lens aberrometer, the CrystalWave IOL aberrometer, and the
like.
[0097] Referring now to FIG. 4, treatment of eye E often begins by
aligning body 104 with the eye. Body 104 will often be moved
horizontally (in the X-Y plane) so as to align an optical axis 116
of the laser treatment system and tissue-shaping surface 112 or
112' with the corneal tissues. The eye may be imaged through body
104 as schematically illustrated in FIG. 5, and known image
processing techniques can be used to identify a position and
orientation of the eye with reference to a pupil P, features of the
iris I, an outer edge of the iris or limbus L, or the like. Body
104 and/or eye E may be moved horizontally so as to align a center
C of pupil P with a center 122 of surface 112 or 112'.
Additionally, body 104 may be rotated about axis 116 so as to align
an stigmatism axis A of eye E with a cylindrical axis 124 of
surface 112 or 112'.
[0098] Positioning of the eye E relative to body 104 may be
determined using a variety of methods and systems for tracking
torsional orientation and position of an eye, including those
described in U.S. Patent Publication No. US2003/0223037, the full
disclosure for which is incorporated herein by reference. Such
tracking techniques often make use of the striations in the iris I
and the location of the pupil boundary for torsional and horizontal
positioning, respectively. This information may be provided to the
various motion stages of support system 106 (see e.g. FIG. 1H) to
drive body 104 into alignment with the eye. Alternatively, the eye
may be aligned with the axis 116 by relying, in at least some
dimensions, upon fixation of the eye on a viewing target, with
engagement between the tissue-shaping surface 112 or 112' into the
eye occurring only when the alignment is within an acceptable
range, such as when any alignment offsets are less than or equal to
desired thresholds.
[0099] As described in additional details elsewhere herein,
absolute alignment between positioning surface 112 or 112' and the
tissue of the eye need not be provided. So long as the alignment is
within an acceptable range, some adjustment of the effective
location of the imposed refractive shape may be provided by
adjusting the laser target surface. If the engagement between the
tissue-shaping surface 112 or 112' and eye is sufficiently
inaccurate that offsets (either horizontally, between pupil center
C and surface center 122, or torsionally between astigmatism axis A
and cylinder axis 124) exceeds a desired threshold, then the body
104 may be disengaged from the eye, the eye or the body
repositioned, and the body again being advanced into engagement
with the eye. This may continue until the alignment offsets are
within the desired thresholds. The thresholds may be established so
as to allow sufficient adjustment to the final refractive
correction using changes to the laser target surface, so that the
depth range of the laser target surface may effect the acceptable
alignment offsets. Calculation of the laser target surface, and
changes to the laser target surface so as to accommodate alignment
offsets, may be implemented using any of a wide range of optical
analytical tools that have been developed and commercialized,
including those used for customized wavefront-based laser eye
surgery and the like.
[0100] Once body 104 and the eye E are sufficiently aligned, the
body is pressed against the corneal tissues of the eye so that the
corneal tissues can form to the shape of surface 112 or 112'. The
cornea need not conform to surface 112 or 112' throughout the
entire tissue-shaping surface and/or cornea, so long as the cornea
conforms to the desired shape throughout an optically used portion
U of the corneal tissues of eye E. While the cornea conforms to
surface 112 or 112', the laser energy from a laser can be focused
at a spot, and the spot can be scanned along a target laser surface
within the cornea.
[0101] Structures and methods for focusing and scanning the laser
spot within the cornea so as to incise the corneal tissue are
described in a variety of references, including U.S. Pat. Nos.
6,325,792 and 6,899,707, the contents of which are incorporated
herein by reference. Laser systems and devices for forming
incisions in the cornea using focused laser energy (often for use
in LASIK procedures) may be commercially available from Abbott
Medical Optics, Inc. and others. Known corneal laser incision
techniques often incise the cornea along a plane, often while the
corneal surface is applanated so as to form a thin epithelial flap
of relatively constant thickness. Embodiments of the present
invention will often vary the target laser surface from such a
plane (or other standard surface shape, such as a sphere or the
like). By conforming the corneal tissue to a desired shape such as
by use of tissue-shaping surface 112 or 112', and by incising the
cornea along a plane or other target surface, a desired refractive
correction of the cornea can be effected.
[0102] Referring now to FIG. 6, some of the optical and support
system components are schematically illustrated. Shaping body or
deformation mechanism 104 is mounted in a receptacle 140 having a
rotational drive for rotating the shaping body about the axis 116,
as indicated by arrows 142. Translation of shaping body 104 along
axis 116 so as to engage the shaping body against eye E is provided
by a Z axis translation/engagement motion stage 144, while
horizontal positioning of the shaping body in the X-Y plane is
effected using a two dimensional X-Y translation stage 146. In some
embodiments, one or more of these motions may be manually effected,
such as by having the system user pre-position body 104 at an
orientation appropriate for the patient's astigmatism axis.
[0103] To effect lateral scanning of the laser energy from laser
102, a two dimensional scanning mirror 148 optionally pivots in two
dimensions, as indicated by arrows 150. Alternative arrangements
may employ a first scanning mirror to scan the laser energy along
the X axis, and a second scanning mirror having a pivot axis
angularly offset from that of the first mirror may provide scanning
primarily along the Y axis. Still further alternative scanning
mechanisms may be employed, including X-Y translation of an offset
imaging lens, and the like. Scanning of the laser spot 126 along
axis 116 may be effected by movement of one or more focusing lens
152 along the optical path in between the laser and eye. As the
scanning rate of the laser spot 126 within the tissue of the eye E
may be quite rapid, it will generally be beneficial to minimize the
weight of any electro mechanical scanning elements, drive the
scanning elements with relatively high speed actuators such as
galvanometers, and the like.
[0104] Many of the remaining optical and control components of
system 100 may be similar to (or modified from) components of
existing laser eye surgery systems. For example, the optical path
may employ a series of beam splitters 154 to selectively direct
portions of the light from eye E, optionally using
wavelength-selective reflection. An image sensor 156 may capture an
image of the eye through shaping body 104 and other components
along the optical path, with the captured image often being used
for establishing and/or verifying alignment between the eye and
shaping body 104, laser spot 126, and other components of the
optical path. Signals from the image sensor 156 may be used to
identify a center of the pupil of eye E, a rotational orientation
of eye E, and the like. Such signals may be used to drive the
various motion stages of support structure 106 and movable optical
components of optics 108 per calculations of processor 22 (see e.g.
FIG. 1H). Images from image sensor 156 may also be used to measure
alignments offsets and the like as described above. Images may also
be displayed on a display screen of the laser eye surgery system,
which may be used in conjunction with (or instead of) direct
viewing of the procedure through binocular microscope 158.
Additional optical and/or mechanical components of system 100 may
also be included, including a fixation target 160, additional
lenses and groups of lenses for processing the light on the optical
path, and the like.
[0105] Referring now to FIGS. 7A and 7B, top and side views,
respectively, of a support arm 162 show many of the components
described above regarding support system 106. The rotational stage
of receptacle 140, the axial translation stage 144, and the
horizontal motion stage 146 may be arranged in a variety of
differing orders, or may be combined or separated into fewer or
more individual stages having different degrees of freedom in a
wide variety of possible arrangements. The receptacle 140 can be
configured to receive shaping body 104 and engage positioning
surfaces of the shaping body so as to allow accurate positioning
and rotation of the shape and body into alignment with the eye.
While a simple latch of the receptacle is schematically
illustrated, no structure of the receptacle will typically extend
beyond the shaping body so as to interfere with engagement between
the shaping surface 112 and the eye E. It should be noted that the
incisions need not absolutely sever the tissues from the eye, as
any relatively small remaining connection points may be detached by
mechanical excision, such as by simply pulling the substantially
severed tissues. After ablation or photoalteration along the target
laser surface or surfaces is complete, shaping body 104 may be
retracted away from the eye E and the desired tissue excised from
along the one or more target laser surfaces 236.
[0106] FIG. 8 depicts aspects of a method for providing a surgical
treatment to an eye of a patient, according to embodiments of the
present invention. As illustrated here, method 800 includes
positioning a corneal deformation mechanism against an anterior
surface of the eye of the patient, so as to induce a first
biomechanical conformation within a corneal stromal tissue of the
eye, as shown by step 810. Method 800 also includes delivering a
first photoaltering energy protocol to the eye while the corneal
stromal tissue is in the first biomechanical conformation, so as to
incise the corneal stromal tissue along a first target surface, as
shown by step 820. Further, method 800 includes positioning a
corneal deformation mechanism against the anterior surface of the
eye of the patient, such that the corneal stromal tissue of the eye
assumes a second biomechanical conformation different from the
first biomechanical conformation, as shown by step 830. Method 800
also includes delivering a second photoaltering energy protocol to
the eye while the corneal stromal tissue is in the second
biomechanical conformation, so as to incise the corneal stromal
tissue along a second target surface different from the first
target surface, as shown by step 840. What is more, method 800
includes removing a portion of corneal stromal tissue disposed
between the first and second target surfaces, as depicted by step
850.
[0107] According to some embodiments, the corneal deformation
mechanism may include an applanation assembly. For example, the
applanation assembly may provide a first shape configuration and a
second shape configuration, such that when in the first shape
configuration, the applanation assembly is shaped to induce the
first biomechanical conformation with the corneal stromal tissue,
and when in the second shape configuration, the applanation
assembly is shaped to induce the second biomechanical conformation
within the corneal stromal tissue. In some cases, the corneal
deformation mechanism may include an applanation plate and a
removable body. The removable body may be constructed of a material
having an index of refraction of about 1.377, for example. In some
instances, the removable body may be removed from the applanation
plate during the first positioning and delivering steps.
Optionally, the removable body may be coupled with the applanation
plate, and may contact the anterior surface of the eye during the
second positioning and energy delivery steps.
[0108] After the tissue volume is removed, and as the cornea heals,
the effect of the photoalteration flap cuts is in some cases
similar to that of an excimer-laser ablated tissue removal, and
thus the photoalteration technique can produce an equivalent or
substantially equivalent effect to that of refractive surgery with
excimer lasers. According to some embodiments, it is helpful to
select the lens or deformation mechanism material such that it is
very close, if not identical, to that of the corneal stroma, i.e.,
1.377. The creation, or manufacturing, of the lens or deformation
mechanism can be similar or identical to that used for the
development of normal intraocular lenses. Hence, the manufacturing
process may include aspects of molding, polishing, measuring of the
power, quality control, and the like, which are similar or
identical to processes used for the manufacture of intraocular
lenses. According to some embodiments, spherical lenses of
deformation mechanisms with given discrete values can be pre-made
and used to deform the corneal tissue during a treatment. Toric
lenses can also be made in a similar way. According to some
embodiments, customized lenses or deformation mechanisms can be
made, which consider low order aberrations, high order aberrations,
and combinations thereof.
[0109] FIG. 9 shows a procedural flow chart for deformation
mechanism or lens manufacture, as well as patient treatment,
according to embodiments of the present invention. Method 900 may
include, for example, obtaining a refraction measurement of a
patient eye as depicted by step 910. Further, aspects of the
process 900 may include manufacturing a lens or deformation
mechanism based on the refraction measurement, as depicted by step
920. Lenses, deformation mechanisms, or applanation assembly
components can be fabricated using laser ablation processes, and
may incorporate standard techniques for the manufacture of
intraocular lenses, aspects of which are described in U.S. Pat.
Nos. 4,856,234, 5,322,649, and 5,888,122, as well as U.S. Patent
Publication No. 2002/0082690. The content of each of these patent
publications is incorporated herein by reference. For example, step
920 may include manufacturing a lens according to standard
intraocular lens fabrication techniques, such that the shape of the
lens is based on measured refractive properties of the eye, and the
lens shape corresponds to the refractive correction intended for
the eye. Accordingly, when the lens is used in a treatment
procedure such as that depicted in FIGS. 1A to 1E (employed as lens
104a, for example), the effect is similar to that of a refractive
volumetric ablative resculpting procedure performed with an excimer
laser, because both the instant technique and the excimer technique
involve cutting or removing an amount of tissue having a certain
volume and shape from the eye or corneal stroma. As part of a
surgical treatment procedure, aspects of the process may include
applanating a patient's eye, or otherwise positioning a corneal
deformation mechanism against an anterior surface of the eye of the
patient so as to induce a first biomechanical conformation within a
corneal stromal tissue of the eye, as depicted by step 940.
Further, process 900 may include creating a first flap cut, for
example with a femtosecond laser, or otherwise delivering a first
photoaltering energy protocol to the eye while the corneal stromal
tissue is in the first biomechanical conformation so as to incise
the corneal stromal tissue along a first target surface, as
depicted by step 950. As shown here, process 900 may also include
putting the lens to a patient interface, or otherwise positioning
the corneal deformation mechanism against the anterior surface of
the eye of the patient, such that the corneal stromal tissue of the
eye assumes a second biomechanical conformation different from the
first biomechanical conformation, as depicted by step 930. Further,
the method 900 may include creating a second flap cut, for example
with a femtosecond laser, or otherwise delivering a second
photoaltering energy protocol to the eye while the corneal stromal
tissue is in the second biomechanical conformation, so as to incise
the corneal stromal tissue along a second target surface different
from the first target surface, as depicted by step 960. What is
more, method 900 may include removing a portion of corneal stromal
tissue disposed between the first and second target surfaces or
flap cuts, as depicted by step 970. In some cases, removal of the
tissue debris or lenticule may include lifting the flap and wiping
out the debris or tissue volume using a clinical wiper. In some
cases, a phacoemulsification process can be employed and a vacuum
can be used to suction out the debris or lenticule without the
lifting of the flap, thereby reducing a possible biomechanical
effect and induction of high order aberrations. Finally, the method
may include putting the flap back or allowing the first and second
target surfaces to engage, as depicted by step 980.
[0110] FIGS. 10A and 10B present a top view and a side view,
respectively, of a patient interface (PI). As shown in FIG. 11A, in
some cases, a pre-made lens or deformation mechanism component 1110
may include a first side 1112 having a flat surface, and a second
opposing side 1114 having a curved surface. Accordingly, the flat
side 1112 can be fitted into a lens holder 1120 which is created to
fit to the patient interface (PI) 1130. In use, the patient
interface 1130 can be fit to a suction system 1140, an eye holder
1142 at the top of the suction system 1140, which often includes or
can be coupled with a suction or vacuum source, can be pressed to
or positioned at the patient surgical eye, and suction can be
started, as shown in FIG. 11B. Where the deformation mechanism
component or pre-formed lens 1110 incorporates a material with
having an index of refraction which approximates that of the eye,
femtosecond energy passing through the flat side 1112 and into the
eye which is in contact with the opposing side 1114 is therefore
not refracted by the lens 1110. In this way, the applied
photoalteration energy can provide a precise and exacting fluence
so as to create a flat cut (e.g. relative to or parallel with the
flat surface 1112. The photoaltered or incised target surface is
biomechanically defined by the engagement between the lens (e.g.
the curved side 1114) and the cornea. Accordingly, the effect is
similar to that of refractive surgery performed with an excimer
laser, because both the instant technique and the excimer technique
involve cutting or removing an amount of tissue having a certain
volume and shape from the eye or corneal stroma.
[0111] FIG. 11A depicts the lens 1110, holder 1120, and patient
interface 1130, where the patient interface is not fit to the
suction system 1140, whereas FIG. 11B shows the suction system 1140
as attached and secured to the patient interface 1130. According to
some embodiments, after the suction is initiated or completed, the
eye can be applanated and a flap type cut can be performed. During
the formation of a first cut or photoalteration, which may be
performed with a laser 1115 such as an IntraLase.TM. femtosecond
laser system, a blank block can be used to govern a baseline, in a
manner similar to that depicted in FIG. 1B. In some instances, a
block or applanation mechanism component 1116 can be cylindrical in
shape, or optionally a block, with a height H that is equivalent to
the depth D of the lens holder recess 1122, as depicted in FIG.
11C. For the second cut, which can also be formed using laser 1115,
the pre-made lens or deformation mechanism 1110 is used in a manner
similar to that depicted in FIG. 1C. This way, the first flap cut
or photoalteration can provide a an incision surface corresponding
to a baseline, and the second flap cut or photoalteration can
provide an incision surface corresponding to the profile of the
pre-made lens.
[0112] According to some embodiments, once the two flap cuts are
performed, a phacoemulsification system or technique can be used to
sonicate or disrupt the lenticule, and to suction out or aspirate
the lenticule or tissue debris from a side hole. In some cases,
aspects of this procedure can be programmed in an IntraLase.TM.
system, for example for performance during the first or the second
flap cut. This way, the biomechanical effect of flap cuts can be
largely reduced. After the bubbles dissipate and the cornea heals,
an excimer-like refractive surgery is complete and the eye's vision
is treated or corrected.
[0113] Fabrication or manufacture techniques for a pre-made lens or
deformation mechanism may share many similarities with procedures
for generating excimer laser ablation targets. For example, FIGS.
12A and 12B show the lens profile of a pre-made lens for a -4 D
myopic correction and a +2 D hyperopic correction, respectively. As
shown here, the height H of the lens base 1210a, 1210b is identical
or substantially similar to the depth of the lens holder, such that
the baseline can be correctly defined. For the first flap cut, a
glass block or cylinder with the same depth of the lens holder
(e.g. as shown in FIG. 11C) can be used. For the second cut, the
pre-made lens (e.g. 1200a, 1200b) can be used. The difference of
the two cuts (e.g. first photoalteration performed using block or
cylinder, second photoalteration performed using pre-made lens)
defines the profile or volumetric lenticule to be cut or excised
from the eye.
[0114] According to some embodiments, as depicted in FIGS. 13A and
13B, a deformation mechanism 1310, which may optionally include or
be coupled with a pre-cut lens or auxiliary deformation element
1320, can be used to deform the corneal tissue, and the
photoablation can be administered so as to incise and remove an
anterior corneal portion 1330, which may include both corneal
stroma and epithelium. In this way, embodiments encompass a one-cut
photorefractive keratectomy (PRK) technique for laser eye
surgery.
[0115] Lenses can be fabricated using laser ablation processes, and
may incorporate standard techniques for the manufacture of
intraocular lenses, aspects of which are described in U.S. Pat.
Nos. 4,856,234, 5,322,649, and 5,888,122, as well as U.S. Patent
Publication No. 2002/0082690. The content of each of these patent
publications is incorporated herein by reference.
[0116] According to some embodiments, such profiles can include an
optical zone and a transition zone, similar to those provided in
excimer-laser refractive surgery techniques. Within the optical
zone, the profile can be identical to an excimer-laser ablation
profile target.
[0117] According to embodiments of the present invention, it is
possible to use a lens material with an index of refraction that is
not identical to that of the corneal stroma, for example where
precise control of the molding of the lens is performed. An
advantage of using a lens material with an index of refraction
identical or substantially similar to that of the stroma is that it
provides for ease of manufacturing of the lens, testing of the
lens, and use of existing intraocular lens technologies. For
complex shapes, such as wavefront-guided CustomVue.TM. treatments,
a different technology may be used. In this case, it may be
desirable to use a lens material that does not have to have
identical index of refraction of the stroma. Assuming the index of
the refraction of the lens material is n.sub.m, and the index of
refraction of the stroma is n.sub.s, which is 1.377 as commonly
used in the industry, the effective optical path difference (OPD)
can be adjusted to be:
S n = n m - 1 n s - 1 S e ( 1 ) ##EQU00001##
[0118] Here, S.sub.n is the OPD for the lens, S.sub.e is the OPD
for excimer laser, n.sub.s is the index of refraction for stroma,
and n.sub.m is the index of refraction for the lens material. For
example, when using a lens material with n.sub.m=1.5, a -4 D lens
can measure at -5.3 D when the lens is profiled. This aspect can be
considered during the testing of the lens.
[0119] According to some embodiments, systems and methods may
involve pre-fabrication of a number of different lenses with
different refractive corrections. For a spherical correction (e.g.
no cylinder), it can be relatively straightforward, because for
every quarter diopter, 4 lenses can be used. Therefore, to cover a
refractive range from -12 D to +9 D, it is possible to
pre-fabricate 84 such lenses. For a toric lens with cylindrical
correction, it is possible to fabricate a lens for a specific
refractive power for every 15 degrees of cylindrical correction for
every quarter diopter of cylinder, and there can be multiple
combinations. Such lenses can be fabricated according to techniques
which are used to create intraocular lenses.
[0120] As described herein, by employing various combinations of
femtosecond laser technology, phacoemulsification techniques,
and/or intraocular lens design fabrication processes, it is
possible to perform a refractive surgery without the use of an
excimer laser.
[0121] Embodiments of the present invention further encompass
systems and methods for use in cataract surgery procedures, where a
cataract or natural lens is removed or treated, but instead of or
as a supplement to the introduction of an intraocular or refractive
lens, a portion of corneal tissue is removed as described herein.
Such techniques may be desirable with, for example, a 4 mm optical
zone, the lens having a power of about 20 diopters, optionally in
combination with a correction for refractive error of the cornea.
In this way, embodiments encompass a lens-less cataract surgery or
crystalline lens removal approach to treating the eye of a patient.
By providing a machine-implemented treatment within the cornea
(e.g. removal of a volume defined by two or more photoalteration
surfaces), as opposed to a physician-implemented treatment
involving placement of the intraocular lens, procedural
efficiencies can be realized.
[0122] The methods and apparatuses of the present invention may be
provided in one or more kits for such use. The kits may comprise a
system for profiling an optical surface, such as an optical surface
of an eye, and instructions for use. Optionally, such kits may
further include any of the other system components described in
relation to the present invention and any other materials or items
relevant to the present invention. The instructions for use can set
forth any of the methods as described herein.
[0123] Each of the calculations or operations described herein may
be performed using a computer or other processor having hardware,
software, and/or firmware. The various method steps may be
performed by modules, and the modules may comprise any of a wide
variety of digital and/or analog data processing hardware and/or
software arranged to perform the method steps described herein. The
modules optionally comprising data processing hardware adapted to
perform one or more of these steps by having appropriate machine
programming code associated therewith, the modules for two or more
steps (or portions of two or more steps) being integrated into a
single processor board or separated into different processor boards
in any of a wide variety of integrated and/or distributed
processing architectures. These methods and systems will often
employ a tangible media embodying machine-readable code with
instructions for performing the method steps described above.
Suitable tangible media may comprise a memory (including a volatile
memory and/or a non-volatile memory), a storage media (such as a
magnetic recording on a floppy disk, a hard disk, a tape, or the
like; on an optical memory such as a CD, a CD-R/W, a CD-ROM, a DVD,
or the like; or any other digital or analog storage media), or the
like.
[0124] All patents, patent publications, patent applications,
journal articles, books, technical references, and the like
discussed in the instant disclosure are incorporated herein by
reference in their entirety for all purposes.
[0125] While the above provides a full and complete disclosure of
exemplary embodiments of the present invention, various
modifications, alternate constructions and equivalents may be
employed as desired. Consequently, although the embodiments have
been described in some detail, by way of example and for clarity of
understanding, a variety of modifications, changes, and adaptations
will be obvious to those of skill in the art. Accordingly, the
above description and illustrations should not be construed as
limiting the invention, which can be defined by the claims.
* * * * *