Full depth laser ophthalmic surgical system, methods of calibrating the surgical system and treatment methods using the same

Abstract

A full depth ophthalmic surgical system includes a femtosecond laser source and an optical coherence tomographer. The system is capable of performing surgical procedures along the entire length of the eye from the cornea to the retina. In one embodiment, the system uses a removeable focal point extension assembly to extend the reach of the focal point location of the laser beam to the vitreous humor of the eye. In another embodiment, the optical system of the ophthalmic surgical system is optimized to focus the laser beam and imaging light in the vitreous humor of the eye. For procedures performed posterior to the lens, a method for calibrating the full depth ophthalmic surgical system uses the focal zone of the optical coherence tomographer beam as a proxy for the focal zone of the femtosecond laser source to. The system can be used to perform treatment in the vitreous humor, including treating floaters and liquification of the vitreous humor.

1 . A full depth ophthalmic surgical system for performing surgery on eyes of subjects, comprising:
 a femtosecond laser source configured to produce a pulsed laser beam;   an imaging assembly comprising an optical coherence tomographer;   a scanning assembly for deflecting the laser beam;   a first patient interface device configured to engage an eye of a subject and configured to be removably connected to the scanning assembly, the first patient interface device having a first predefined optical power;   a second patient interface device configured to engage an eye of a subject and configured to be removably connected to the scanning assembly, the second patient interface device having a second predefined optical power which is less positive or more negative than the first predefined optical power, the first patient interface and the second patient interface being alternatively connected to the scanning assembly; and   a controller operably connected to the laser source, the imaging assembly and the scanning assembly and programmed to:   operate the optical coherence tomographer to scan an imaging beam in a first eye in a first region including a lens of the first eye and structures anterior to the lens when the first patient interface is engaged with the first eye and connected to the scanning assembly, thereby obtaining image information corresponding to the first region of the first eye;   operate the scanning assembly to scan a focal spot of the laser beam in the first region of the first eye to treat a tissue in the first region when the first patient interface is engaged with the first eye and connected to the scanning assembly;   operate the optical coherence tomographer to scan an imaging beam in a second eye in a second region including structures posterior to a lens of the second eye when the second patient interface is engaged with the second eye and connected to the scanning assembly, thereby obtaining image information corresponding to the second region of the second eye; and   operate the scanning assembly to scan a focal spot of the laser beam in the second region of the second eye to treat a tissue in the second region when the second patient interface is engaged with the second eye and connected to the scanning assembly.   
     
     
         2 . The system of  claim 1 , wherein each of the first and the second patient interface device comprises:
 a body having an upper end and a lower end;   wherein the upper end is configured to be removably attached to an objective lens assembly of the ophthalmic surgical system;   a flexible suction ring disposed at the lower end of the body, configured to engage the eye via a vacuum force; and   an optical assembly disposed within the body and having the respective optical power.   
     
     
         3 . The patient interface of  claim 2 , wherein the optical assembly of the second patient interface device is a doublet lens. 
     
     
         4 . A full depth ophthalmic surgical system for performing surgery on an eye of a subject, comprising:
 a femtosecond laser source configured to produce a femtosecond pulsed laser beam;   an imaging assembly configured to emit an imaging beam;   a scanning assembly including a Z scanner and an XY scanner, configured to scan a focal spot of the laser beam and the imaging beam within the eye in a depth direction and two transverse directions, respectively;   an illumination light source configured to emit an illumination light;   a video camera assembly;   an objective lens assembly configured to focus the laser beam and the imaging beam;   a patient interface configured to be coupled to the objective lens assembly and to engage the eye, the patient interface including a lens having a predefined optical power; and   optical components including at least one beam splitter, configured to direct the laser beam and the imaging beam output by the scanning assembly and the illumination light to the objective lens assembly, and to direct light emitted from within the eye, which has passed through the objective lens assembly, to the video camera assembly;   wherein the scanning assembly, the objective lens assembly and the lens of the patient interface are configured to form a focal spot of the laser beam at any depth within a range of 15 mm to 24 mm in water beyond a distal surface of the lens of the patient interface.   
     
     
         5 . The ophthalmic surgical system of  claim 4 , wherein the illumination light source is a ring-shaped light source, wherein the video camera assembly includes a detector and a tunable lens in front of the detector, and wherein the tunable lens of the video camera assembly is configured to focus light emitted from any distance within a range of 8 mm to 29 mm in water beyond the distal surface of the lens of the patient interface. 
     
     
         6 . The ophthalmic surgical system of  claim 5 , wherein the objective lens assembly and the focusing lens of the patient interface are configured to form an image of the illumination light source at locations 0 to 10 mm from a distal surface of the lens of the patient interface. 
     
     
         7 . The ophthalmic surgical system of  claim 4 , wherein the objective lens assembly includes four doublet lenses and a meniscus lens. 
     
     
         8 . The ophthalmic surgical system of  claim 4 , wherein the imaging assembly comprises an optical coherence tomographer, a Purkinje imaging assembly, or a Scheimpflug imaging assembly. 
     
     
         9 . The ophthalmic surgical system of  claim 4 , further comprising a fixation light source configured to generate a fixation light, wherein the optical components are further configured to direct the fixation light to the objective lens assembly. 
     
     
         10 . The ophthalmic surgical system of  claim 4 , wherein the XY scanner includes two scanning mirrors, and wherein the objective lens assembly and the lens of the patient interface are configured to form respective images of the two scanning mirrors at locations 0 to 10 mm from a distal surface of the focusing lens of the patient interface. 
     
     
         11 . The ophthalmic surgical system of  claim 4 , further comprising a controller operably connected the laser source, the imaging assembly, the scanning assembly, and the video camera assembly and programmed to:
 operate the imaging assembly to form images of structures within a vitreous humor of the eye;   identify outer boundaries of a treatment volume located in the vitreous humor based on the images;   define a scan pattern for scanning the focal spot of the laser beam within the treatment volume; and   operate the scanning assembly to scan the focal spot of the laser beam in the treatment volume in the vitreous humor according to the scan pattern to liquify the vitreous humor in the treatment volume.   
     
     
         12 . The ophthalmic surgical system of  claim 4 , further comprising a controller operably connected to the laser source, the imaging assembly, the scanning assembly, and the video camera assembly and programmed to:
 operate the imaging assembly or the video camera assembly to form images of structures in a vitreous humor of the eye;   identify floaters located in the vitreous humor based on the images;   define a treatment volume within the vitreous humor that includes the identified floaters;   define a scan pattern for scanning the focal spot of the laser beam within the treatment volume; and   operate the scanning assembly to scan the focal spot of the laser beam in the treatment volume in the vitreous humor according to the scan pattern to destroy or remove the floaters.   
     
     
         13 . A method for treating a vitreous humor of an eye of a subject using a laser ophthalmic surgical system, the ophthalmic surgical system including an ultrafast laser system, an optical coherence tomographer, and shared optical components, the method comprising:
 operating the shared optical components to scan a focal zone of a light beam of the optical coherence tomographer in a region of the eye posterior to a lens of the eye;   detecting an intensity of the light beam after it is reflected from the eye;   determining a depth of a retina of the eye based the detected intensity of the reflected light beam;   setting a first safe limiting depth which is at a predetermined distance from the depth of the retina in an anterior direction;   determining another depth of another structure of the eye based the detected intensity of the reflected light beam;   setting a second safe limiting depth which is at another predetermined distance from the depth of the other structure in a posterior direction; and   based on the first and second safe limiting depths, operating the shared optical components to scan a focal zone of a laser beam of the ultrafast laser within a volume of the eye between the first safe limiting depth and the second safe limiting depth.   
     
     
         14 . The method of  claim 13 , wherein the other structure of the eye is a posterior lens capsule of the eye. 
     
     
         15 . A method of liquefying a portion of a vitreous humor of an eye, comprising:
 irradiating at least a portion of the vitreous humor of the eye with a focal spot of a pulsed laser beam emitted from a laser source, the laser beam comprising laser pulses having a wavelength of 1000-1100 nm, a pulse width of 100-1000 fs, a pulse energy of 2-20 μJ, a repetition rate of 1-500 kHz, and a total energy of less than 40 J.   
     
     
         16 . The method of  claim 15 , wherein the laser pulses have a wavelength of 1030 nm, a pulse width of 400 fs, a pulse energy of 9 μJ, a repetition rate of 6-24 kHz, and a total energy of 10-40 J. 
     
     
         17 . The method of  claim 15 , further comprising, prior to the irradiating step:
 operating an imaging system to image structures of the vitreous humor;   determining outer boundaries of the portion of the vitreous humor for treatment; and   defining a scan pattern for scanning the focal spot of the pulsed laser beam within the portion of the vitreous humor.