Patent Publication Number: US-2023157887-A1

Title: Performing laser vitreolysis on an eye with an intraocular lens

Description:
TECHNICAL FIELD 
     The present disclosure relates generally to ophthalmic laser surgical systems, and more particularly to performing laser vitreolysis on an eye with an intraocular lens. 
     BACKGROUND 
     In ophthalmic laser surgery, a surgeon may direct a laser beam into an eye to treat the eye. For example, in laser vitreolysis, a laser beam is directed into the vitreous to disintegrate eye floaters. Eye floaters are clumps of collagen proteins that form in the vitreous. These clumps disturb vision with moving shadows and distortions. The laser beam may be used to remove the floaters, thus improving vision. 
     BRIEF SUMMARY 
     In certain embodiments, an ophthalmic laser system includes a laser device and a computer, where the laser device includes a laser and a phase modulator. The laser device directs a laser beam towards a target in an eye, where an intraocular lens (IOL) is disposed within the eye. The IOL has a phase profile that yields an IOL phase shift of light entering the eye. The laser generates the laser beam. The phase modulator has a phase front that yields a first phase shift of the laser beam that changes to a second phase shift when the laser beam reaches the IOL. The second phase shift is an inverse to the IOL phase shift. 
     Embodiments may include none, one, some, or all of the following features: 
     The target comprising an eye floater. 
     The phase modulator comprises a diffractive optical element or a spatial light modulator. The computer may program the spatial light modulator to yield the first phase shift. 
     The computer determines the IOL phase shift, calculates the second phase shift as an inverse of the IOL phase shift, and calculates the first phase shift from the second phase shift. The computer may determine the IOL phase shift by measuring the phase shift of the IOL. The computer may calculate the first phase shift from the second phase shift by determining how the first phase shift changes between the phase modulator and the IOL according to wavefront propagation theory. 
     The ophthalmic laser system includes an ophthalmic microscope that gathers light reflected from within the eye to yield an image of the eye. The ophthalmic microscope may be, e.g., a slit lamp. 
     In certain embodiments, a method for performing laser vitreolysis includes instructing, by a computer, a laser device to direct a laser beam towards a target in an eye. An intraocular lens (IOL) is disposed within the eye and has a phase profile that yields an IOL phase shift of light entering the eye. The laser device includes a laser and a phase modulator. The phase modulator has a phase front that yields a first phase shift of the laser beam that changes to a second phase shift when the laser beam reaches the IOL, where the second phase shift is an inverse to the IOL phase shift. The laser beam is generated by the laser. The laser beam is modulated by the phase modulator to yield the first phase shift of the laser beam. The laser beam is directed by the laser device towards the target in the eye. 
     Embodiments may include none, one, some, or all of the following features: 
     The target comprising an eye floater. 
     The phase modulator comprises a diffractive optical element or a spatial light modulator. The computer may program the spatial light modulator to yield the first phase shift. 
     The method further includes: determining, by the computer, the IOL phase shift; calculating, by the computer, the second phase shift as an inverse of the IOL phase shift; and calculating, by the computer, the first phase shift from the second phase shift. The computer may determine the IOL phase shift by measuring a phase shift of the IOL. The computer may calculate the first phase shift from the second phase shift by determining how the first phase shift changes between the phase modulator and the IOL according to wavefront propagation theory. 
     The method further includes gathering, by an ophthalmic microscope, light reflected from within the eye to yield an image of the eye. The ophthalmic microscope may be a slit lamp. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    illustrates an example of an ophthalmic laser system that an operator may use to perform laser vitreolysis on a patient eye to remove vitreous floaters, according to certain embodiments; 
         FIG.  2    illustrates an example of phase modulator that adds a phase shift to a laser beam  120  treating an eye, according to certain embodiments; and 
         FIG.  3    illustrates an example of phase modulator that adds a phase shift to a laser beam  120  treating an eye, according to certain embodiments. 
     
    
    
     DESCRIPTION OF EXAMPLE EMBODIMENTS 
     Referring now to the description and drawings, example embodiments of the disclosed apparatuses, systems, and methods are shown in detail. The description and drawings are not intended to be exhaustive or otherwise limit the claims to the specific embodiments shown in the drawings and disclosed in the description. Although the drawings represent possible embodiments, the drawings are not necessarily to scale and certain features may be simplified, exaggerated, removed, or partially sectioned to better illustrate the embodiments. 
     Some laser vitreolysis patients have a multifocal intraocular lens (IOL) implanted into their eye. A multifocal IOL adds a phase shift that diffracts incoming light to different focal points along the axis of the eye, allowing the patient to see objects at different distances. However, the IOL also diffracts a laser beam used to treat floaters to different focal points. Moreover, the laser beam may have a wavelength that causes the IOL to create even more focal points. That is, the IOL disperses and reduces laser energy at the floater, and may even cause laser energy to reach the retina. 
     Accordingly, the systems described herein add a phase profile to the laser beam that compensates for the phase shift caused by the IOL. For example, the systems include a phase modulator that adds a phase profile F 1  to the laser beam. The laser beam enters the eye and the phase front changes to phase front F 2 , which is designed to be the inverse of the phase shift F 3  generated by the IOL. As the laser beam passes through the IOL, phase shift F 3  compensates for the phase shift F 2 , such that the IOL behaves as a monofocal lens with only one focus. 
       FIG.  1    illustrates an example of an ophthalmic laser system  10  that an operator (with an operator eye  12 ) may use to perform laser vitreolysis on a patient eye  14  to remove vitreous floaters, according to certain embodiments. Ophthalmic laser system  10  allows the operator to see floaters in relation to the retina and lens of the eye, and then direct a laser beam to break up the floaters. In the illustrated example, patient eye  14  has an axis (visual or optical) that defines a z-axis. The z-axis defines an x-axis and a y-axis orthogonal to the z-axis. In turn, the x-axis and the y-axis define an xy-plane. In the example, patient eye  14  includes a multifocal IOL (not shown). Examples of multifocal IOLs include diffractive and/or refractive multifocal, extended depth of focus, presbyopic, light adjustable multifocal, or other IOL. 
     In this document, inverse phase shifts have the same magnitude but are opposite in sign. For example, a +x phase shift is the inverse of a −x phase shift. Also in this document, the phase shifts of the IOL and the treatment laser are inverse at the wavelength of the treatment laser. For example, a multifocal IOL is typically designed to yield a phase shift at the wavelength of maximal retinal sensitivity. However, in this document, the phase shifts of the IOL and the treatment laser are inverse (i.e., equal in magnitude but of different signs) at the wavelength of the treatment laser. 
     In the example, ophthalmic laser system  10  comprises oculars  20 , a laser delivery head  22 , a slit illumination source  26 , a positioning device (such as a joystick  28 ), a base  30 , and a console  32 , coupled as shown. Laser delivery head  22  includes a laser fiber  34 , a distal end  35 , a zoom system  36 , a collimator  38 , a mirror  40 , a phase modulator  41 , and an objective lens  42 , coupled as shown. Slit illumination source  26  includes a light source  43 , condenser lens  44 , a variable aperture  45 , a variable slit plate  46 , a projection lens  47 , and a mirror  48 . Console  32  includes a computer (such as a controller  50 ), a laser  52 , and a user interface  54 , coupled as shown. 
     As an overview, ophthalmic laser system  10  includes a laser device  16  (e.g., laser  52 , laser fiber  34 , and laser delivery head  22 ) and an ophthalmic microscope  18  such as a slit lamp (e.g., oculars  20 , objective lens  42 , mirror  48 , and slit illumination source  26 ). Operator eye  12  utilizes the optical path from oculars  20  through mirror  40 , phase modulator  41 , objective lens  42 , and mirror  48  to view patient eye  14 . A laser beam follows the laser path from laser  52  through laser delivery head  22  and mirror  48  to treat patient eye  14 . In other embodiments, system  10  includes any suitable treatment system with a laser device, any suitable imaging system, and any suitable computer. 
     According to the overview, laser device  16  directs a laser beam towards a target in an eye. The eye has an intraocular lens (IOL) having a phase profile configured to yield an IOL phase shift of the laser beam. Laser  52  generates the laser beam. Phase modulator  41  has a phase front that yields a first phase shift of the laser beam that changes to a second phase shift when the laser beam reaches the IOL, where the second phase shift is the inverse to the IOL phase shift. As the laser beam passes through the IOL, the IOL phase shift compensates for the second phase shift, such that the IOL behaves as a monofocal lens with only one focus. 
     In more detail, in certain embodiments, oculars  20  allow operator eye  12  to view patient eye  14 . Laser delivery head  22  delivers a laser beam of laser pulses from laser  52  of console  32  to patient eye  14 . Laser fiber  34  of delivery head  22  transports the laser beam from laser  52  to the end of fiber  34 . Zoom system  36  includes optical elements that change the spot size of the laser beam that exits fiber  34 . Collimator  38  collimates the laser beam, and mirror  40  directs the beam to phase modulator  41 . 
     Phase modulator  41  adds phase shift F 1  to the laser beam to yield a phase profile F 1 . Phase modulator  41  may comprise, e.g., a diffractive optical element (such as one embodied in a glass plate) or a spatial light modulator (such as a programmable diffractive optical element). Phase modulator  41  may be instructed by controller to add the phase shift F 1 . In certain embodiments, controller  50  may instruct phase modulator  41  to adjust to a particular phase shift F 1 , depending on the IOL phase shift F 3  of the IOL in the patient eye. 
     Objective lens  42  focuses the beam. Zoom system  36  and collimator  38  are configured to direct a parallel laser beam to mirror  40 , in order to focus the laser beam onto the image plane of ophthalmic microscope  18 . Mirror  40  may be a dichroic mirror that is reflective for the laser beam wavelength and transmissive for visible light. 
     Slit illumination source  26  of laser system  10  provides light that illuminates the surgical site of patient eye  14 . Slit illumination source  26  includes light source  43 , which emits light such as a high-intensity illumination light. Condenser lens  44  directs the light towards variable aperture  45  and variable slit plate  46 . Variable aperture  45  defines the height of the light in the y-direction, and variable slit plate  43  defines the width of the light in the x-direction to form the light into a slit shape. Projection lens  47  directions the light towards prism mirror  48 , which directs the slit of light into patient eye  14 . 
     Base  30  supports laser delivery head  22  and slit illumination source  26 . Joystick  28  moves base  30  in the x-, y-, and z-directions. Console  32  includes components that support the operation of system  10 . Controller  50  of console  32  controls of the operation of components of system  10 , e.g., base  30 , laser delivery head  22 , slit illumination source  26 , laser  52 , and/or user interface  54 . Laser  52  supplies the laser beam. Any suitable laser  30  may be used, e.g., a femtosecond or nanosecond laser (e.g., Q-switched) with any suitable crystal (e.g., Nd:YAG, Erbium:YAG, Ti: Sapphire, or ruby). The laser beam may have any suitable wavelength, e.g., in a range from 500 nm to 1100 nm. User interface  54  communicates information between the operator and system  10 . 
     Controller  50  controls the operation of system  10 . In certain embodiments, controller  50  instructs phase modulator  41  to apply the first phase shift F 1  to the laser beam. In addition, in certain embodiments, controller  50  calculates the phase shift F 1 . In the embodiments, controller  50  determines the IOL phase shift F 3 , calculates the second phase shift F 2  as an inverse of the IOL phase shift F 3 , and calculates the first phase shift F 1  from the second phase shift F 2 . 
     In certain cases, the IOL phase shift may be provided by the manufacturer. In other cases, controller  50  determines the IOL phase shift F 3  by measuring the phase shift of the IOL. For example, controller  50  may use any of the following to measure the IOL phase shift: contact profilometer, confocal microscope, white light interferometer, optical aberrometer, interferometer, confocal chromatic microscope, atomic force microscope, etc. In certain embodiments, closed-loop adaptive optics can be used to measure phase shift F 3 . In the embodiments, a detector (such as a two-photon fluorescence detector) detects light reflected from the eye as the adaptive optics are adjusted and is used to determine when the optics are properly adjusted, which provides the measurement of phase shift F 3 . 
     In the embodiments, controller  50  calculates the second phase shift F 2  as an inverse of the IOL phase shift F 3 . Controller  50  then calculates the first phase shift F 1  from the second phase shift F 2  by determining how the first phase shift F 1  changes between phase modulator  41  and the IOL according to wavefront propagation theory. 
       FIG.  2    illustrates an example of phase modulator  41  that adds a phase shift to a laser beam  120  treating an eye  110 , according to certain embodiments. In the example, eye  110  includes a cornea  112 , an iris  114 , and a multifocal IOL  116 . Multifocal IOL  116  is designed to add a phase shift F 3 ( r ) to light entering eye  110 . A floater  118  is in the vitreous of eye  110 . 
     As an example of operation, laser beam  120  is directed towards eye  110 . Lens  122  directs laser beam  120  towards phase modulator  41 . Phase modulator  41  adds a phase profile F 1 ( r ) to laser beam  120 . Laser beam  120  enters eye  110 , and the phase front F 1 ( r ) changes to phase front F 2 ( r ) when laser beam  120  reaches multifocal IOL  116 . Phase front F 2 ( r ) is the inverse of the phase shift F 3  generated by the IOL. As the laser beam passes through the IOL, phase shift F 3  compensates for the phase shift F 2 , such that the IOL behaves as a monofocal lens with only one focus at laser spot  124  at floater  118 . 
       FIG.  3    illustrates another example of phase modulator  41  that adds a phase shift to laser beam  120  treating eye  110 , according to certain embodiments. In the example, eye  110  includes cornea  112 , iris  114 , and multifocal IOL  116 . Multifocal IOL  116  is designed to add a phase shift F 3 ( r ) with, e.g., a + 3 -diopter power to light entering eye  110 . Phase modulator  41  adds a phase profile F 1 ( r ) to laser beam  120 . Phase front F 1 ( r ) changes to phase front F 2 ( r ) when laser beam  120  reaches multifocal IOL  116 . Phase front F 2 ( r ) is the inverse of the phase shift F 3 ( r ) generated by the IOL. As the laser beam passes through the IOL, phase shift F 3 ( r ) compensates for the phase shift F 2 ( r ), such that IOL  116  behaves as a monofocal lens with only one focus at laser spot  124  at floater  118 . 
     A component (such as the control computer) of the systems and apparatuses disclosed herein may include an interface, logic, and/or memory, any of which may include computer hardware and/or software. An interface can receive input to the component and/or send output from the component, and is typically used to exchange information between, e.g., software, hardware, peripheral devices, users, and combinations of these. A user interface is a type of interface that a user can utilize to communicate with (e.g., send input to and/or receive output from) a computer. Examples of user interfaces include a display, Graphical User Interface (GUI), touchscreen, keyboard, mouse, gesture sensor, microphone, and speakers. 
     Logic can perform operations of the component. Logic may include one or more electronic devices that process data, e.g., execute instructions to generate output from input. Examples of such an electronic device include a computer, processor, microprocessor (e.g., a Central Processing Unit (CPU)), and computer chip. Logic may include computer software that encodes instructions capable of being executed by an electronic device to perform operations. Examples of computer software include a computer program, application, and operating system. 
     A memory can store information and may comprise tangible, computer-readable, and/or computer-executable storage medium. Examples of memory include computer memory (e.g., Random Access Memory (RAM) or Read Only Memory (ROM)), mass storage media (e.g., a hard disk), removable storage media (e.g., a Compact Disk (CD) or Digital Video or Versatile Disk (DVD)), database, network storage (e.g., a server), and/or other computer-readable media. Particular embodiments may be directed to memory encoded with computer software. 
     Although this disclosure has been described in terms of certain embodiments, modifications (such as changes, substitutions, additions, omissions, and/or other modifications) of the embodiments will be apparent to those skilled in the art. Accordingly, modifications may be made to the embodiments without departing from the scope of the invention. For example, modifications may be made to the systems and apparatuses disclosed herein. The components of the systems and apparatuses may be integrated or separated, or the operations of the systems and apparatuses may be performed by more, fewer, or other components, as apparent to those skilled in the art. As another example, modifications may be made to the methods disclosed herein. The methods may include more, fewer, or other steps, and the steps may be performed in any suitable order, as apparent to those skilled in the art. 
     To aid the Patent Office and readers in interpreting the claims, Applicants note that they do not intend any of the claims or claim elements to invoke 35 U.S.C. § 112(f), unless the words “means for” or “step for” are explicitly used in the particular claim. Use of any other term (e.g., “mechanism,” “module,” “device,” “unit,” “component,” “element,” “member,” “apparatus,” “machine,” “system,” “processor,” or “controller”) within a claim is understood by the applicants to refer to structures known to those skilled in the relevant art and is not intended to invoke 35 U.S.C. § 112(f).