Patent Application
20130041354
1. Field of the Invention
The field of the present invention is generally related medical devices, systems, and methods for their use, typically for measuring and/or treating tissues of an eye and, more particularly, to provide a common reference structure from which to base measurements of internal tissues of the eye, and from which to direct treatments toward selected targets so as to correct refractive defects of the eye, treat ophthalmic disease states, and/or the like.
2. Background
Various laser procedures or operations benefit from a laser beam that is properly directed to a specific target within the patient's eye. For example, in an ophthalmic laser surgery where eye tissue is to be photoaltered, the post-treatment quality of the patient's vision may largely depend on correct targeting of the laser beam. Such ophthalmic surgical procedures can rely on laser targets on or in the cornea, sclera, iris, eye lens, capsular bag and other structures of the eye. A precision targeting of the laser beam is also beneficial in many non-ophthalmic laser procedures. Existing laser eye surgery systems do a very good job of directing the laser beam toward the intended targets.
Along with the accuracy of the targeting and beam directing systems, modern laser eye treatment systems benefit from high-quality measurement data. A variety of specialized diagnostic tools have been developed to facilitate highly accurate refractive prescriptions to be developed. In particular, wavefront aberrometers have recently revolutionized laser eye surgery by providing accurate and practical measurements of the high-order refractive defects throughout the optical system. This has allowed customized photoalteration shapes or prescriptions to be derived that address the specific defects of a particular patient's eye. The combination of wavefront aberrometry and customized laser treatments can often provide final visual acuities of better than 20/20 for many patients. Such highly advantageous outcomes may be more common when the relationship between the eye measurement data and the position of the eye during treatment is known quite accurately.
For many patients, the refractive laser treatment is directed to an interior stromal tissue within a patient's cornea. In LASIK, that stromal tissue is accessed by cutting and displacing a thin flap from the anterior corneal surface, with the cut optionally being performed using a femtosecond laser. One way to accurately position the eye relative to the femtosecond laser system is to use a contact lens to shape and stabilize the eye. The position of the contact lens (typically a flat or curved glass plate referred to as an “applanation lens”) relative to the laser system is generally sufficiently known for the accurate targeting of the laser light beam, as it can be mounted to the laser system. When a flat applanation lens is used, it engages the cornea so that the applanation lens flattens the eye, thus creating a reference surface where the lens and the eye contact. Curved applanation lenses create a similarly conformed curved reference surface. The desired flap can then be cut largely by targeting a flap surface at a fixed depth into the cornea from the applation lens surface.
Femtosecond cutting of LASIK flaps and customized laser eye surgery provide great benefits for many patients. However, as with all successes, still further improvements might be desirable. Some patients with thinner corneas are not good candidates for LASIK, depending on the depth of the flap and/or the depth of tissue to be photoaltered in the refractive correction. Unfortunately, flattening the eye also can increase intraocular pressure. In some cases, applanation can result in patient gray-out and black-out in the applanated eye, and can cause ripples in deep lamellar cuts. Curved applanation lenses that more closely approximate the shape of the eye can be used, but may also not be a good fit with all corneas, may complicate scanning patterns, and/or may add cost and complexity to the surgery system. Both curved and flat applanation lenses may also displace internal structures within the eye. Hence, extension of the known ophthalmic measurement and treatment techniques and tools to allow improved ophthalmic therapies may benefit from improved systems and methods.
Thus, a need remains for the systems and methods which can target the laser light to the patient eye for the photoalteration of the eye tissue without the shortcomings of the present devices.
Embodiments of the present invention provide systems and methods for laser therapies directed to internal targets in the eye of a patient. Typically, an ophthalmic measurement system acquires location data of one or more structures in the eye. A controller often calculates the target locations based on the location data received from the ophthalmic measurement system, and a laser emits a laser beam to ablate, photoalter, or otherwise treat the target locations received from the controller (for instance, portions of the cornea, lens, capsular bag, or another structure of the eye). A common reference surface is provided for the laser system and the ophthalmic measurement system, with the common reference surface typically being included in a patient interface that is attached to the eye using a suction ring or the like. The laser and the ophthalmic measurement system can couple with the patient interface sequentially, or the measurement and laser systems can be integrated into an overall diagnostic and photoalteration assembly which couples with the patient interface. The patient interface may engage the eye outside the optically used cornea, and without conforming the optically used cornea to a predetermined shape.
Various laser sources may be used with the inventive method and system, including infrared, visible, and UV lasers. Further, the laser sources used with the inventive methods and systems may be a continuous wave, Q-switched pulse, or mode-locked ultrashort pulse lasers, including femtosecond or picosecond ranges of light pulse duration. Some examples of the ophthalmologic measurement system are an optical coherence tomographer (OCT), a wavefront aberrometer, and a topographer.
In one embodiment, a laser surgery system for treatment of the eye has a patient interface with a reference surface and an eye-engagement surface configured to attach with the eye; an ophthalmic measurement system that, in use, generates location data corresponding to internal surfaces of the eye, where the measurement system is coupleable with the reference surface; a laser that is coupleable with the reference surface; and a controller that is coupleable with the ophthalmic measurement system and the laser. The controller is configured to process location data from the ophthalmic measurement system and to compute laser target data so that the laser photoalters an internal target within the eye in response to the location data.
In one aspect, the eye engagement surface is a substantially annular area outside of a treated area of the eye, thus inhibiting distortion of the internal target within the eye.
In another aspect, the patient interface system further has a substantially planar or spherical lens for contacting the eye. The lens conforms a central cornea of the eye to a substantially planar or spherical shape.
In yet another aspect, the ophthalmologic measurement system is an optical coherence tomographer, a wavefront aberrometer, a topographer, or a combination thereof.
In another aspect, the coupling of the ophthalmic measurement system and the laser with the reference surface is performed sequentially.
In yet another aspect, the ophthalmic measurement system and the laser are housed in a photoalteration apparatus capable of coupling with the reference surface, thus referencing the ophthalmic measurement system and the laser with the reference surface simultaneously.
In another embodiment, a system for laser surgery treatment of the eye which, in use, generates a location data corresponding to internal surfaces of the eye using an ophthalmic measurement system, which calculates internal targets within the eye based on the location data using a controller, and which photoalters the internal targets within the eye using a laser has a patient interface with a reference surface configured to couple with the laser and the ophthalmic measurement system, and an eye-engagement surface configured to attach with the eye.
In yet another embodiment, a method for laser surgery treatment of the eye has the steps of engaging a patient interface with the eye of a patient, the patient interface having a reference surface; coupling an ophthalmic measurement system with the reference surface; generating location data corresponding to internal surfaces of the eye using the ophthalmic measurement system; coupling the measurement system with a controller so that the controller computes an internal target within the eye in response to the location data; coupling the laser with the reference surface; coupling the laser with the controller; and ablating the internal target with the laser light.
In one aspect, the location data corresponding to internal surfaces of the eye are periodically refreshed, thus enabling the internal target within the eye to be refreshed.
In another aspect, the patient interface is discarded after every use.
One or more exemplary embodiments of the present invention will hereinafter be described in conjunction with the following drawings, wherein like reference numerals denote like components:
Embodiments of the present invention can be used to direct laser light to the target areas in the patient's eye. The laser light photoalters the target areas in the eye, for example, portions of the cornea or eye lens, in order to improve vision of the patient, or to provide an access for a subsequent surgery by cutting a flap in the cornea or opening an aperture in the capsular bag. The target areas for the laser photoalteration are calculated by a controller based on the location data received from an ophthalmic measurement system, for example, an optical coherence tomographer, a wavefront aberrometer, or a topographer. A patient interface attached to the patient's eye provides a common reference surface for the attachment of the laser and the ophthalmic measurement system.
Referring now to
The photoalteration apparatus 10 has an ophthalmic measurement system, a controller, and a laser. Docking the photoalteration apparatus 10 to the reference surface 102 can simultaneously register the ophthalmic measurement system and the laser to the reference surface 102. A sequential docking of the ophthalmic measurement system and the laser to the reference surface is also possible, as explained below with reference to
The laser 112 provides a pulsed laser beam for photoalteration via a chirped pulse laser amplification system, such as described in U.S. Pat. No. RE37,585, for example. U.S. Pat. Publication No. 2004/0243111 also describes other methods of photoalteration, the entire disclosures of which are incorporated herein. 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, the entire disclosure of which is incorporated herein, 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 spot. Focusing optics preferably direct the pulsed laser beam toward the eye for plasma mediated (e.g., non-UV) photodisruption of tissue.
The pulsed laser beam has physical characteristics similar to those of the laser beams generated by a laser system disclosed in U.S. Pat. No. 4,764,930, the entire disclosure of which is incorporated herein, U.S. Pat. No. 5,993,438, or the like. For example, a non-UV, ultrashort pulsed laser beam is produced 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 photodisruption of the tissue, the pulsed laser beam has a wavelength that permits the pulsed laser beam to pass through the cornea without absorption by the corneal tissue. The wavelength of the pulsed laser beam 18 is generally in the range of about 3 μm about 1.9 nm, and preferably between about 400 nm to about 3000 nm. The irradiance of the pulsed laser beam is preferably greater than the threshold for optical breakdown of the tissue. Although a non-UV, ultrashort pulsed laser beam is described in this embodiment, the pulsed laser beam may have other pulse durations and different wavelengths in other embodiments.
The beam may be scanned by selectively moving the focal spot of the beam to produce a structured scan pattern (e.g., a raster pattern, arcs, linear segments, rings, cylinders, a spiral pattern, or the like) of scan spots. The step rate at which the focal spot is moved is referred to herein as the scan rate. Exemplary operating scan rates are between about 10 kHz and about 400 kHz, or at any other desired scan rate. 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.
In one embodiment, scanning mirrors or other optics are employed to angularly deflect and scan one or more input beams. For example, scanning mirrors may be driven by galvanometers where each of the mirrors scans along different orthogonal axes (e.g., an x-axis and a y-axis). A focusing objective having one or more lenses can be used to image the input beam onto a focal plane. The focal spot may thus be scanned in two dimensions (e.g., along the x-axis and the y-axis) within the focal plane. Scanning along the third dimension, i.e., moving the focal plane along an optical axis (e.g., a z-axis), may be achieved by moving the focusing objective, or one or more lenses within the focusing objective, along the optical axis. Thus, a variety of scanned paths or patterns are obtainable from the beam.
A variety of techniques may be used to align the scanned pattern with the eye. In some embodiments, iris registration methodology associated with ablation procedures, such as used for LASIK, marking and/or fiducial techniques used with corneal flap creation, keratoplasty, and the like, and centration can be used to align the incision pattern with the eye. For example, U.S. Pat. Nos. 7,261,415 and 7,044,602, which are herein incorporated in entirety by reference, describe registration techniques to track the position of the eye. Additionally, the alignment reference may vary for different refractive corrections and be based on a variety of ocular features. For example, the alignment reference can be based on the pupil center, the iris boundary, and the like. In one embodiment, the alignment of the scanned pattern accounts for pupil center shift, which may occur as a result of inconsistent iris actuation.
At step 210 a patient interface is applied to the patient's eye. An example of applying the patient interface to the patient's eye is illustrated in
At step 215 an ophthalmic measurement system, for instance the optical coherence tomographer, is docked to the patient interface. Since the patient interface maintains its position with respect to the patient's eye, the docked optical coherence tomographer maintains reference to the structures of interest in the eye.
At step 220 an ophthalmic measurement system acquires location data on the structures of interest in the patient's eye. The location data is the position of different tissues in the eye, for example, the cornea and various structures associated therewith (e.g., epithelium, Bowman's layer, stroma, Descemet's membrane, and endothelium), iris, eye lens, or capsular bag.
At step 225 the location data acquired at step 220 are made available to the controller.
At step 230 the optical coherence tomographer is undocked from the patient interface to make the reference surface of the patient interface available to the laser. The reference surface maintains a substantially fixed position to the patient's eye, thus both the ophthalmic measurement system and the laser will also maintain a substantially fixed position to the patient's eye when docked to the patient interface.
At step 235 the controller calculates the laser targets, which are the volumes in the eye to be photoaltered, based on the location data received from the optical coherence tomographer. The laser targets are made available to the laser at step 240.
At step 245 the laser is docked to the patient interface. Thus, the reference surface, which was used to reference the ophthalmic measurement system is now used to reference laser with respect to the structures in the eye.
At step 250 the laser photoalters the laser targets received from the controller. Thus, the tissue of the patient's eye that corresponds to the laser targets is photoaltered by the laser light energy.
At step 255 a check is performed to verify whether all the laser targets have been photoaltered. If more laser targets remain, then they are photoaltered at step 250, followed by repeating the check at step 255. If the last laser target has been photoaltered, then the photoalteration stops at step 260.
The reference surface of the patient interface may not precisely follow the location of the structure of interest in the patient's eye because of the deformation of the eye. Therefore, a refresh of the location data may be desired, as shown at step 255. To refresh the location data, the laser is undocked from the patient interface at step 265, followed by docking the optical coherence tomographer at step 215. The optical coherence tomographer is now ready to acquire additional location data, thus refreshing the location data on the structures of interest in the patient's eye.
The method as described above with reference to
At step 310 a patient interface is applied to the patient's eye. The application of the patient interface to the patient eye makes the reference surface 102 available for referencing the position of the structures of interest in the eye.
At step 315 the photoalteration apparatus is docked to the patient interface. As explained in conjunction with
At step 320 the optical coherence tomographer acquires location data on the structures of interest in the patient's eye. The beamsplitting mirror can be used to reflect the light to the patient's eye and back to the optical coherence tomographer. The location data can be the position of different tissues in the eye, for example, the cornea, eye lens, or capsular bag.
At step 325 the location data acquired at step 320 are made available to the controller, which calculates the laser targets, i.e. the volumes to be photoaltered, at step 330. The laser targets are made available to the laser at step 335. As explained above, docking of the photoalteration apparatus references both the optical coherence tomographer and the laser to the reference surface 102.
At step 340 the laser ablates the laser targets received from the controller. Thus, the tissue of the patient's eye that corresponds to the laser targets is ablated by the laser light energy.
At step 345 a check is performed to verify if all the laser targets have been photoaltered. If some laser targets remain, then they are photoaltered at step 340, followed by repeating the check for the remaining laser targets at step 345. If the last laser target has been photoaltered, then the photoalteration stops at step 355.
A refresh of the location data, which may be desired to account for the deformation of the eye, is shown in step 255. With this embodiment of the invention the refresh of the location data does not necessitate additional docking and undocking of the laser or the optical coherence tomographer.
Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, many variations of the disclosed systems and methods are possible without deviating from the spirit of the invention.
This application is a continuation of prior U.S. application Ser. No. 12/714,146, filed Feb. 26, 2010, which claims the benefit of U.S. Provisional Application No. 61/155,903, filed Feb. 26, 2009.
| Number | Date | Country | |
|---|---|---|---|
| 61155903 | Feb 2009 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12714146 | Feb 2010 | US |
| Child | 13629269 | US |
