Abstract: A system for positioning the eye of a patient, relative to a stationary surgical laser unit, includes a chair for moving the patient. An eye stabilizing element is held against the eye, with a tapered receptacle extending outwardly therefrom. Also, an alignment device with a tapered tip is mounted on the surgical laser unit. In operation, the patient is moved to engage the receptacle of the eye stabilizing element with the tip of the alignment device, to thereby align the patient's eye with the surgical laser unit for laser surgery.

Abstract: A device for establishing a desired alignment between a patient's eye and a laser system to facilitate an engagement therebetween includes a light source to illuminate the eye. A moveable platform is provided to move the patient relative to the laser system. To establish alignment between the eye and the laser system, a reference marker is based on the laser system. An image of the marker, along with reflections from the illuminated eye, is then transmitted to the system controller. There, the image and reflections are processed to determine a measured alignment that is then compared to the desired alignment. An error signal that is indicative of an alignment difference is then generated and used to incrementally move the platform, or the patient, in an appropriate direction.

Abstract: A system for producing polychromatic light having selectively shaped wavefronts includes a source for generating light beams of at least two wavelengths (?1, ?2). The beams are made up of a plurality of contiguous sub-beams that establish ?1 and ?2 wavefronts. From the source, the light is directed toward an optical phase shifting device which can include one or more arrays, with each array having a plurality of elements. Functionally, within a particular array, each element is independently adjustable to selectively alter the optical pathlength of a corresponding sub-beam. For light having two wavelengths (?1, ?2), a first array configuration is used to reshape the ?1 wavelength light and a second array configuration is used to reshape the ?2 wavelength light. After wavefront reshaping, the ?1 and ?2 wavelength light is directed onto a common beam path where it can be viewed, imaged or further processed.

Abstract: A method is disclosed for photodisrupting a surface in the stroma of an eye at a substantially constant distance from the anterior surface of the eye. A frame of reference is established for the eye that includes an axis of rotation. Next, the focal point of a laser beam is positioned in the stroma at a radial distance from the axis. At least one laser pulse is delivered to the stromal tissue at the focal point, photodisrupting the tissue there and creating a photodisruption bubble having a diameter “d”. The focal point is then rotated about the axis through an arc length substantially equal to “d” and the photodisruption step is repeated. During rotation, the distance between the focal point and the axis is decreased at a rate substantially equal to the distance “d” per revolution. The method can be used to create a flap for a LASIK type procedure.

Abstract: A laser system for generating at least one pulse and/or pulse sequence(s) of pulses having at least one specified property, such as pulse energy, duration, peak intensity, pulse form and/or timing includes an amplifying cavity. The amplification process is monitored in the amplifying cavity to obtain data about at least one property of the pulse sequence and/or the single pulse(s). The system also compares the obtained data with reference data and it controls at least one switching means for inputting, outputting and/or retaining the pulse(s) in the amplifying cavity such that at least one property of the pulse sequences and/or the pulses at an output of the laser system has substantially a specified value.

Abstract: A system for measuring the energy of an ultra-short pulse in a laser beam includes a half-wave plate for orienting the polarization of the beam. A polarizing beam splitter is used to reflect a portion of each pulse of the beam and a remainder of the beam is transmitted toward a target. Energy in the reflected portion is measured by a laser energy meter (“LEM”) to determine the energy in the remainder of the beam. An output signal from the LEM is used to obtain an error signal that can then be used to rotate the half-wave plate to control the energy level in the remainder of the beam. In an alternate embodiment, a fixed-ratio beam splitter and a second LEM are used to measure and control the energy in the remainder of the laser beam.

Abstract: A method and apparatus for intrastromal refractive surgery is disclosed wherein tissue at selected locations within the stroma of the cornea is photoablated using a pulsed laser beam. The apparatus includes an optical system for forming a shaped laser beam having a waist at a predetermined distance from the optical system. The pulse duration and pulse energy of the laser beam are selected to cause ablation to occur in front of the waist (i.e. between the waist and the optical system). To achieve this, a pulse energy is used that exceeds the minimum pulse energy required for ablation at the waist. By ablating in front of the waist, a relatively large ablation zone (per pulse) is created (compared to ablation at the waist). Furthermore, while the laser is scanned through the cornea to effectuate a refractive change, the optical system maintains a uniform waist for the laser beam.

Abstract: A system for spatially stabilizing a base point on the optical axis of a patient's eye, for photoablation of the cornea, includes an optical element for identifying the base point. The system also includes an illumination source which is a fixation point for the eye. Movement of the illumination source induces a saccadic movement of the eye wherein the optical axis of the eye moves from a first orientation to a second orientation. Following the saccadic movement of the eye there is a latency period during which the base point, and hence the eye, is substantially stabilized. Movement of the light source is timed to coincide the latency period with the resting period of the patient's heartbeat sequence, and the relaxation period of the patient's respiration cycle. During the latency period, photoablation is accomplished by directing a train of laser pulses from a laser source into the corneal tissue.

Abstract: A closed-loop control system for the intrastromal photoablation of tissue includes an active mirror for individually directing the component beams of a diagnostic laser beam to a focal point on the retina of an eye. The reflected beam is analyzed to identify a distorted wavefront indicative of required corneal corrections, and an induced wavefront indicative of optical aberrations introduced by bubbles formed during tissue ablation. A comparator alters the induced wavefront with a desired wavefront to create a rectified wavefront, and a comparator compares the rectified wavefront with the distorted wavefront to create error signals. The error signals are then used to operate the active mirror and to control an ablation laser until the absence of error signals indicate the required stromal tissue has been photoablated.

Abstract: A system for accurately guiding a laser focal point along a predetermined path within the stroma of a cornea includes a contact lens for conforming the anterior surface of the cornea to a radius of curvature, Rlens, that is approximately 8.3 mm. Conforming the cornea to the lens causes minimal discomfort to the patient and does not upset the three-dimensional architecture of the corneal lamellae. As the focal point is advanced along a path within the cornea, the laser source is selectively translated parallel to the optical axis of the cornea to control the depth of the laser focal point. The movement includes three components: a first component, z1 that is dependent upon the shape of the contact lens, a second component, z2 that compensates for refraction at the surfaces of the contact lens, and a third component, z3, that compensates for refraction caused by the anatomical configuration of the cornea.

Abstract: A method for creating a corneal flap for use in a corneal reshaping procedure includes the step of creating a periphery for the flap by subsurface photoablation of the cornea using a laser beam. Specifically, tissue located at the interface between layers of stromal lamellae is photoablated to create the periphery. To accomplish this, the size of the bubbles created during photoablation are monitored using a wavefront detector and the photoablation depth is altered when the bubble size indicates that photoablation is not occurring at an interface. With the periphery established, an incision is made into the cornea extending between the anterior surface of the cornea and the periphery. Next, the corneal tissue bounded by the incision is lifted to mechanically separate the flap from the remainder of the cornea along the interface between layers of lamellae.

Abstract: An optical system for partitioning and focusing a laser beam into a plurality of focal points to simultaneously photoalter corneal tissue at a plurality of locations includes a laser source. In one embodiment, an active mirror is used to partition the master beam into diverging beams. In another embodiment, a lenslet array in combination with a field lens is used to partition the master beam into seven diverging beams. The resultant diverging beams are then collimated, magnified and focused into a plurality of focal points using a set of optical lenses. Each focal point has an average pulse energy of approximately 5 &mgr;J rendering it suitable for subsurface photoalteration of corneal tissue. A scanning mechanism is provided to move the plurality of focal points, as a group, along a predetermined path through the cornea to quickly and safely photoalter a predetermined volume of subsurface corneal tissue.

Abstract: A device and method for altering the refractive properties of the cornea by photodisrupting stromal lamellae involves focusing a laser beam within the stroma. To effectuate tissue alteration with minimal laser energies, the focal point of the laser beam is maintained inside the stromal lamella, rather than on an interface between layers of lamellae. To maintain the focal point inside the lamella, the bubbles that result from the photodisruption are measured using a wavefront detector. When a large bubble is observed, indicating photodisruption on an interface between layers of lamellae, the depth of the focal point, measured from the anterior surface, is adjusted to thereby resume photodisruption inside a lamella. A wavefront detector can be used to track the progress of the photodisruption procedure, providing information that can be used to update the amounts and locations of stromal tissue that must be removed to obtain the desired refractive correction.

Abstract: A device and method for increasing the accuracy of an ocular laser procedure by detecting and compensating for small eye movements includes the establishment of a corneal reference plane. To create the corneal reference plane, a laser beam is first used to photoablate stromal tissue at three different locations in the cornea. Bubbles that are created upon photoablation define the plane and can be imaged to determine the position of the plane as the eye moves. A pair of cameras and a processor are provided to image the cornea and triangulate the position of the reference plane. The updated position of the corneal reference plane is then used to guide the path of the laser beam during the course of the ocular procedure.

Abstract: A device for detecting a wavefront that is defined by a plurality of contiguous light beams includes an array of lenslets for isolating the individual light beams and focusing each individual light beam to a focal point in an x-y plane. The device also has a plurality of clusters which are positioned in the x-y plane, and each cluster includes a plurality of pixels that are arranged in rows aligned in an x-direction, and columns aligned in a y-direction. Additionally, each pixel of a cluster includes both a first photocell for generating an x-signal and a second photocell for generating a y-signal, respectively, in response to an illumination of the pixel by a light beam. Further, the device includes circuitry for converting the x and y signals to digital signals and then using the digital signals to determine an x-y position for the focal point of the particular light beam that is incident on the cluster.

Abstract: A method for separating lamellae in the stroma of an eye includes establishing a focal depth that will be located in relatively weaker tissue at an interface layer between lamellae in the stroma. A laser beam can then be focused to photoablate stromal tissue and create a photoablative response thereto. This photoablative response is then compared to a reference value using wavefront analysis techniques to determine an effective minimum energy level for the laser beam. Maintenance of a proper focal depth can be periodically verified by maintaining a birefringent reference using an ellipsometer. Once the lamellae are separated, a flap of corneal tissue can be created that can be lifted to expose underlying stromal tissue for further surgical photoablation.

Abstract: A closed-loop control system for the superficial photoablation of stromal tissue from an exposed surface includes an active mirror for directing a diagnostic laser beam through the exposed surface to a focal point on the retina of an eye. The reflected beam is analyzed by a detector to identify a distorted wavefront that is indicative of required corrections, and an induced wavefront that is indicative of optical aberrations that have been mechanically introduced when the stromal tissue was exposed. A compensator alters a desired wavefront with the induced wavefront to create a rectified wavefront. A comparator then compares the rectified wavefront with the distorted wavefront to create an error signal. In the operation of the closed-loop control system, the error signal is used to maintain a focal point on the retina for the diagnostic laser beam. Also, at a null, the error signal indicates when the required amount of stromal tissue has been photoablated.

Abstract: A device and method for establishing an aberration-free delivery system for use in evaluating an optical specimen includes a light source for directing light through the system and along a beam path toward the specimen. A first beam splitter is positioned on the beam path to direct light radiated from the system toward a detector for creation of a first wavefront, and for generation of a signal. In turn, the signal is used to program an active mirror that is also positioned on the beam path, to thereafter establish an aberration-free wavefront for light incident on the optical specimen. Further, a second beam splitter is positioned on the beam path for directing light reflected from the specimen toward the detector for the creation of a second wavefront having characteristics of optical aberrations in the specimen. The second wavefront is then used to further program the active mirror for analysis and evaluation of the optical specimen.