Patent Description:
With significant developments in laser technology and its application to ophthalmology, laser surgery has become the technique of choice for ophthalmic procedures, such as refractive surgery for correcting myopia, hyperopia, astigmatism, and so on, and cataract surgery for treating and/or removing a cataractic lens. Often, a surgeon may prefer a surgical laser beam over manual surgical tools like microkeratomes because the laser beam can be focused precisely on extremely small amounts of eye tissue, thereby enhancing accuracy and reliability of the procedure.

Laser eye surgery generally uses different types of laser beams, such as ultraviolet lasers, infrared lasers, and near infrared, ultra-short pulsed lasers for various procedures and indications. For example, in the commonly-known LASIK (Laser Assisted In Situ Keratomileusis) procedure, an ultra-short pulsed laser is used to cut a corneal flap to expose the corneal stroma for photoablation with an excimer laser that operates in the ultraviolet range. Non-ultraviolet, ultra-short pulsed lasers emit radiation with pulse durations as short as <NUM> femtoseconds and as long as <NUM> nanoseconds, and a wavelength between <NUM> and <NUM>. Besides cutting corneal flaps, ultra-short pulsed laser systems can also be used to perform cataract-related surgical procedures, including opening cataract incisions, capsulotomy, as well as softening and/or breaking of the cataractous lens. They can further be used for lenticule extraction procedures for refractive correction. Examples of laser systems that provide ultra-short pulsed laser beams include Abbott Medical Optics Inc. 's iFS Advanced Femtosecond Laser System and CATALYS Precision Laser System.

<CIT> describes an ophthalmic laser surgery apparatus which includes an irradiation optical system performing irradiation with a laser beam and including an objective lens concentrating a laser, and treats a patient's eye by using the laser beam. The ophthalmic laser surgery apparatus includes a delivery unit that includes an irradiation end unit containing the objective lens, includes at least a portion of the irradiation optical system, and optically guides the laser beam, a first movement unit that includes a first drive section and integrally moves the irradiation end unit and an eyeball fixing unit which is connected to the delivery unit and fixes the patient's eye onto an optical axis of the objective lens, toward the patient's eye by driving the first drive section, a second movement unit that includes a second drive section and moves the eyeball fixing unit with respect to the irradiation end unit by driving the second drive section, and drive control means for controlling driving of the first drive section and driving of the second drive section, and individually moving the first movement unit and the second movement unit.

Optics and lenses for laser systems are typically complex and expensive. Instead of using an expensive lens with a large radius, some laser systems use a beam delivery system to move a lens assembly near an eye to direct the laser beam to different areas of the eye for surgery with a desired small spot size, thereby reducing system cost. The mechanical system which moves the lens assembly must do so with very precise motion control (e.g., micron level accuracy) and at a relatively high rate of speed, and is typically quite heavy.

In addition, it is necessary to stabilize patient's eye during laser surgery in a predetermined position relative to the focal point of the laser beam. This is normally done by physically constraining eye movement during laser surgery by applying an eye docking assembly to the patient's eye prior to the surgery. The eye docking assembly is fixed to the laser surgery system on the one end, and fixes an applanating lens in a patient interface onto the patient's eye on the other end.

During eye surgery under such circumstances, system vibrations have to be maintained so that they are very low, or else any unbalanced vibrations will be applied to the eye. As noted above, however, in a system where a beam delivery system moves a lens assembly during the surgery, it is very difficult to eliminate vibrations. Furthermore, in the case of a loss of electrical power, it is possible that the weight of the beam delivery system may be transferred to the patient's eye.

Accordingly, it would be desirable to provide an arrangement and method whereby the eye of a patient during laser surgery may be maintained in a predetermined position relative to the focal point of a laser beam during laser surgery while reducing the loading imposed upon the eye by any vibrations or movement of the laser eye surgery equipment.

Hence, to obviate one or more problems due to limitations or disadvantages of the related art, in one aspect, the invention provides systems and methods defined by the appended claims.

This summary and the following detailed description are merely exemplary, illustrative, and explanatory, and are not intended to limit, but to provide further explanation of the invention as claimed. Additional features and advantages of the invention will be set forth in the descriptions that follow, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description, claims and the appended drawings.

A better understanding of the features and advantages will be facilitated by referring to the following detailed description that sets forth illustrative embodiments using principles of the invention, as well as to the accompanying drawings, in which like numerals refer to like parts throughout the different views. Like parts, however, do not always have like reference numerals. Further, the drawings are not drawn to scale, and emphasis has instead been placed on illustrating the principles of the invention. All illustrations are intended to convey concepts, where relative sizes, shapes, and other detailed attributes may be illustrated schematically rather than depicted literally or precisely.

Exemplary embodiments of laser surgery systems and eye stabilization devices are described below to illustrate various aspects and advantages of these devices and methods are described below. For purposes of explanation, specific configurations and details are set forth so as to provide a thorough understanding of the embodiments. It will also, however, be apparent to one skilled in the art that embodiments of the present invention can be practiced without certain specific details. Further, to avoid obscuring the embodiment being described, various well-known features may be omitted or simplified in the description. It should be understood that the principles involved in these devices and methods can be employed in a variety of other contexts, and therefore the novel devices and method disclosed and claimed here should not be construed as being limited to the example embodiments described below.

<FIG> illustrates an example embodiment of an arrangement <NUM> of a laser surgery system <NUM> and an eye stabilization device. <FIG> also illustrates a coordinate system for arrangement <NUM>, including an X direction (horizontal in <FIG>), a Y direction (in and out of the page in <FIG>), and a Z direction (vertical in <FIG>).

Laser surgery system <NUM> includes a structural frame or base <NUM>, a gantry <NUM> movable in three dimensions and attached to the structural frame; an adjustable table <NUM> attached to gantry <NUM>; a docking receptacle <NUM>; a lens assembly <NUM> attached to adjustable table <NUM>; one or more sensors <NUM>; one or more connectors <NUM> and <NUM> which resiliently connect docking receptacle <NUM> to gantry <NUM>; one or more sensors <NUM>; a laser <NUM>; and a controller <NUM>.

Here, the eye stabilization device comprises an eye docking assembly <NUM> including an applanating lens <NUM>. Eye docking assembly <NUM> is configured to be docked or connected to docking receptacle <NUM> to form a patient interface for laser surgery. Beneficially, eye docking assembly <NUM> is a single-use disposable element which is attached to an eye <NUM> of a patient in advance of laser surgery.

<FIG> is a sort of "hybrid" illustration which illustrates certain structural elements such as structural frame <NUM>, gantry <NUM>, adjustable table <NUM>, docking receptacle <NUM>, lens assembly <NUM>, and eye docking assembly cross-sectionally, and which shows other elements such as sensor(s) <NUM>, connector(s) <NUM>, sensor <NUM>, laser <NUM>, and controller <NUM> as functional blocks.

Lens assembly <NUM> includes a lens <NUM> and an optical structure <NUM> holding lens <NUM> and providing an optical path for laser light from laser <NUM> to pass through lens assembly <NUM>, and specifically to pass through lens <NUM>.

In some embodiments, one or more of connector(s) <NUM> may be a spring. In some embodiments, one or more of connector(s) <NUM> may be a voice coil.

In some embodiments, structural frame <NUM> may be fixed or attached to ground <NUM>, for example by one or more bolts. In other embodiments, structural frame <NUM> may not be fixed to ground <NUM>, and may include one or more wheels which allow it to be moved. Beneficially, the wheels may have a locking mechanism so that laser surgery system <NUM> does not move once it is placed in position for a laser surgery. Beneficially, structural frame <NUM> may have a substantial mass and weight, for example several tens of pounds or more (e.g., <NUM> pounds), so as to create a substantial frictional force between structural frame <NUM> and ground <NUM>.

Controller <NUM> may include one or more processors and associated memory (e.g., random access memory (RAM), FLASH memory, read only memory (ROM), etc.) which may store therein computer-readable instructions for one or more algorithms to be executed by the processor(s) of controller <NUM>. Although not shown in <FIG>, controller <NUM> may receive one or more sensing signals from sensor(s) <NUM> and/or sensor(s) <NUM>, and may provide one or more control signals to adjustable table <NUM>, connector (e.g., voice coil) <NUM>, and/or laser <NUM> to control operations thereof.

Gantry <NUM> is attached the structural frame <NUM> and is movable relative to structural frame <NUM>, and in particular movable in the Z direction.

Adjustable table <NUM> is attached to gantry <NUM>. Beneficially, adjustable table <NUM> is movable in three mutually orthogonal directions (e.g., the X direction, the Y direction, and the Z direction) relative to gantry <NUM>. Adjustable table <NUM> is configured to move lens assembly <NUM> in the three mutually orthogonal directions relative to eye <NUM>. Beneficially, adjustable table <NUM> may be moved under control of one or more control signals received from controller <NUM>.

Here, adjustable table <NUM> includes a first arrangement of an X stage <NUM> and a Y stage <NUM> configured to move lens assembly <NUM> in the X direction and Y direction, and a Z stage <NUM> configured to move the lens assembly in the Z direction in response to one or more control signals from controller <NUM> so as to focus the laser light at a desired depth of the patient's eye <NUM> for laser surgery.

Beneficially, one or more sensor(s) <NUM> sense the distance Z" between a surface of gantry <NUM> and a surface of adjustable table <NUM>, and in response thereto output(s) to controller <NUM> one or more sensing signals. In some embodiments, one or more sensor(s) <NUM> may sense a change in the distance Z" between the surface of gantry <NUM> and the surface of adjustable table <NUM>, and in response thereto output(s) to controller <NUM> one or more sensing signals.

Connector(s) <NUM> and <NUM> resiliently attach docking receptacle <NUM> to gantry <NUM>. Here, "resiliently" is understood to mean connected in such a way that the docking receptacle <NUM> and gantry <NUM> may move relative to each other in response to external forces. In particular, for example, connector(s) <NUM> may comprise springs which may compress and expand in response to external forces, and connector(s) <NUM> may comprise voice coils which may move by the reaction of a magnetic field in response to a current passing through it, for example a current supplied by controller <NUM>. Connectors <NUM> and <NUM> connect docking receptacle <NUM> and gantry <NUM> so that there is a distance Z" between a surface of gantry <NUM> and a surface of docking receptacle <NUM> which is attached resiliently to gantry <NUM>. Connector(s) <NUM> and <NUM> may dynamically adjust the distance between the surface of gantry <NUM> and the surface of docking receptacle <NUM>. For example, spring(s) <NUM> may expand or compress to dynamically adjust the distance between the surface of gantry <NUM> and the surface of docking receptacle <NUM>, and voice coil(s) <NUM> may adjust the distance between the surface of gantry <NUM> and the surface of docking receptacle <NUM> in response to a current passing through the voice coil <NUM>.

Beneficially, one or more sensor(s) <NUM> sense the distance Z" between the surface of gantry <NUM> and the surface of docking receptacle <NUM>, and in response thereto output(s) to controller <NUM> one or more sensing signals. In some embodiments, one or more sensor(s) <NUM> may sense a change in the distance Z" between the surface of gantry <NUM> and the surface of docking receptacle <NUM>, and in response thereto output(s) to controller <NUM> one or more sensing signals.

Controller <NUM> may control movement of adjustable table <NUM> in response to the sensing signal(s) to maintain a target distance in the Z direction between lens assembly <NUM> and a reference area of eye docking assembly <NUM>.

In some embodiments, laser <NUM> may be provided as a separate device, apart from the rest of laser surgery system <NUM>. In some embodiments, structural frame <NUM> may be provided as a separate element to which the rest of laser surgery system <NUM> is attached or connected.

<FIG> illustrates an example of a portion of a laser surgery system which employs a camera in an eye docking procedure. Here, laser surgery system <NUM> is a variation of laser surgery system <NUM> and so a repeated description of the common elements between laser surgery system <NUM> and laser surgery system <NUM> will not be repeated.

Laser surgery system <NUM> includes a mirror or beamsplitter <NUM> and an imaging device (e.g., a camera) <NUM>. Here, beamsplitter <NUM> and an imaging device <NUM> may be configured to be removably inserted into between lens assembly <NUM> and docking receptacle <NUM>, for example under the control of one or more motors (not shown), after adjustable table <NUM> is moved far away from docking receptacle <NUM>. As will be described in greater detail below, in some embodiments imaging device <NUM> may produce image data for a patient's eye <NUM> and provide this image data to a user via a heads-up display and/or to controller <NUM>, wherein the image data may be used to control movement of gantry <NUM> to dock eye docking assembly <NUM> to docking receptacle <NUM> during an eye docking procedure prior to the commencement of laser surgery on the patient's eye <NUM>.

<FIG> is a flowchart of a method <NUM> of docking an eye to a laser surgery system (e.g., laser surgery system <NUM>) for performing a laser surgery procedure.

In an operation <NUM>, eye docking assembly <NUM> is attached with docking receptacle <NUM>.

In an optional operation <NUM>, the patient's eye <NUM> may be monitored by imaging device <NUM> during the docking procedure in embodiments where laser surgery system <NUM> includes imaging device <NUM>.

At this point, prior to docking, the load on resilient connector(s) (e.g., springs) <NUM> and the weight of docking receptacle <NUM> produce a balance at an initial distance of distance Z" = Z"INIT.

In an operation <NUM>, gantry <NUM> is moved toward the patient's eye <NUM> so as to dock eye docking assembly <NUM> with the patient's eye <NUM>. During docking, a docking force F is created, where F = Ks(Z" - Z"INIT) - FV, where FV is a motive force generated by connector(s) (e.g., voice coil(s)) <NUM> in response to the current which is caused to pass therethrough by controller <NUM>. Accordingly, it is seen that the docking force may be controlled by the current through the voice coil(s) <NUM>. Here, sensor(s) <NUM> may provide one or more sensing signals to controller <NUM> from which controller <NUM> may determine Z" and in response to which control the movement of gantry <NUM> and the current through voice coil(s) <NUM> to provide a smooth docking procedure with minimal loading on the patient and patient's eye <NUM>. At this point, if beamsplitter <NUM> and imaging device <NUM> were employed in the docking procedure, then they may be removed from the path between lens assembly <NUM> and docking receptacle <NUM>.

In an operation <NUM>, eye docking assembly <NUM> is attached to the patient's eye <NUM> by any of a variety of methods which are known in the art.

<FIG> is a flowchart of a method <NUM> of performing laser eye surgery. In some embodiments, method <NUM> may be performed subsequent to an eye docking procedure such as method <NUM>.

In an operation <NUM>, a laser surgery system, for example a controller of the laser surgery system (e.g., laser surgery system <NUM>) determines a target distance DOPT between lens assembly <NUM> and eye docking assembly <NUM>, in particular between lens assembly <NUM> and a reference area of the eye docking assembly, such as the top surface of applanating lens <NUM>.

In an operation <NUM>, one or more sensors (e.g., sensor(s) <NUM>) sense a displacement Z' between adjustable table <NUM> and gantry <NUM>. Sensor(s) <NUM> output one or more sensing signals including a Z stage position sensing signal to controller <NUM>.

In an operation <NUM>, one or more sensors (e.g., sensor(s) <NUM>) sense a displacement between gantry <NUM> and docking receptacle <NUM>. In some embodiments, sensor(s) <NUM> sense the distance Z" between a surface of gantry <NUM> and a surface of docking receptacle <NUM> which is attached resiliently to gantry <NUM> by the one or more connectors <NUM> and/pr <NUM>. In some embodiments, sensor(s) <NUM> sense a change in the distance Z" between the surface of the gantry and the surface of the docking receptacle. Sensor(s) <NUM> may output one or more sensing signals to controller <NUM>.

In an operation <NUM>, in response to the sensing signal(s) from sensor(s) <NUM> and/or sensor(s) <NUM>, controller <NUM> controls adjustable stage <NUM> to maintain the target distance DOPT between lens assembly <NUM> and eye docking assembly <NUM>, in particular between lens assembly <NUM> and a reference area of the eye docking assembly, such as the top surface of applanating lens <NUM>. In some embodiments, controller <NUM> may control a motive force of one or more voice coils <NUM> by passing a controlled current therethrough to maintain the target distance DOPT between lens assembly <NUM> and eye docking assembly <NUM>.

In an operation <NUM>, under control of controller <NUM>, laser surgery system <NUM> generates a laser beam and passes the laser beam through lens assembly <NUM> and moves lens assembly to direct the laser beam to one or more target areas on the patient's eye <NUM> to perform a predetermined laser surgery procedure on the patient's eye <NUM>. Throughout operation <NUM>, while the laser is on during the surgery, controller <NUM> causes optical assembly <NUM> to track movement of patient's eye <NUM> in the Z direction to maintain the distance DOPT between lens assembly <NUM> and eye docking assembly <NUM> regardless of how patient's eye <NUM> moves in the Z direction during the procedure, thus preventing optical assembly <NUM> from touching docking receptacle <NUM>, eye docking assembly <NUM>, or applanating lens <NUM>.

Through the use of resilient connectors, for example spring(s) <NUM> and voice coil(s) <NUM> vibration forces of adjustable table <NUM> may be added onto gantry <NUM> and the heavy structural frame <NUM> to which gantry <NUM> is attached instead of being loaded onto the patient's eye <NUM> via docking receptacle <NUM>. And in the event that electrical power is lost, the resultant docking force is F = W + Ks(Z" - Z"INIT), where W is the small weight of eye docking assembly <NUM> and docking receptacle <NUM>.

The use of the terms "a" and "an" and "the" and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated here or clearly contradicted by context. The term "connected" is to be construed as partly or wholly contained within, attached to, or joined together, even if there is something intervening. Recitation of ranges of values here are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described here can be performed in any suitable order unless otherwise indicated here or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate embodiments of the invention, and does not pose a limitation on the scope of the invention unless otherwise claimed.

Claim 1:
A system, comprising:
a structural frame (<NUM>);
a gantry (<NUM>) attached to the structural frame and movable relative to the structural frame;
a docking receptacle (<NUM>) configured to be removably attached to an eye docking assembly (<NUM>) which is attached to an eye;
one or more connectors (<NUM>, <NUM>) configured to resiliently attach the docking receptacle to the gantry;
an adjustable table (<NUM>) attached to the gantry and movable in three mutually orthogonal directions relative to the gantry;
a lens assembly (<NUM>) attached to the adjustable table, wherein the adjustable table is configured to move the lens assembly in the three mutually orthogonal directions relative to the eye;
at least one sensor (<NUM>) configured to sense at least one of (<NUM>) a distance between a surface of the gantry and a surface of the docking receptacle which is attached resiliently to the gantry by the one or more connectors, and (<NUM>) a change in the distance between the surface of the gantry and the surface of the docking receptacle, and in response thereto to output at least one sensing signal; and
a controller (<NUM>) configured to control movement of the adjustable table in response to the at least one sensing signal to maintain a target distance between the lens assembly and a reference area of the eye docking assembly.