News Column

Patent Application Titled "Ophthalmologic Laser Device and Method for Preventing and Treating Aftercataract" Published Online

July 31, 2014



By a News Reporter-Staff News Editor at Politics & Government Week -- According to news reporting originating from Washington, D.C., by VerticalNews journalists, a patent application by the inventors Dick, Manfred (Gefell, DE); Kuehnert, Juergen (Jena, DE); Reich, Matthias (Jena, DE), filed on July 26, 2012, was made available online on July 17, 2014.

The assignee for this patent application is Carl Zeiss Meditec Ag.

Reporters obtained the following quote from the background information supplied by the inventors: "In the prior art, ophthalmologic laser devices are used in all areas of the eye. For example, in laser-assisted intrastromal keratomileusis (LASIK), with the aid of a microkeratome a stromal flap having a thickness of approx. 160 .mu.m is detached from the cornea and folded open. The material-removing laser treatment is then performed in the intrastromal tissue thereby exposed, and after the treatment the flap is folded closed. With this procedure, patients have minimal pain and a rapid recovery of sight after the operation. Alternatively, the material-removing laser treatment can be carried out in a photorefractive keratectomy (PRK) on the stromal surface, after the upper epithelial layer, which is about 50 .mu.m thick, has been irreversibly removed from the Bowman membrane with hockey knives. In both cases, an ArF excimer laser is used for refractive correction of the cornea by ablation of tissue.

"In addition, femtosecond lasers have recently been used to make incisions in the cornea (femto-LASIK). Such apparatuses are also called laser microkeratomes. In this context, photodisruption is generated in the target volume, leading to a minimal blistering in the stromal tissue. If a target spot is placed on a target spot by means of a scanner system, any desired incisions (perforations) can be introduced into the cornea. Such incisions are also called laser incisions in the following. It is known from US 2006/0155265 A1, for example, to cut the flap by means of a femtosecond laser system. The ablation of the stromal tissue required for refractive correction is then carried out in a known manner by means of an excimer laser, so that mechanical manipulation can be omitted completely. However, two laser systems are necessary.

"WO 2004/105661 A1 describes using the fs laser to cut an intrastromal lenticule, which can be removed, for example, through relatively small openings with the aid of suitable tweezers or also cannulas, in order to modify the refractive properties of the cornea. Furthermore, intrastromal pockets can be prepared by this method, into which artificial inlays can be introduced for refractive correction.

"What is known as laser photocoagulation is performed in the fundus of the eye for various diseases of the retina, for example detached retina. As a rule, lasers emitting continuous waves (cw) are used for this purpose. The main field of application of photocoagulation is for focussing the metabolism on the still healthy regions of the retina by obliterating diseased tissue. Photocoagulation may moreover stimulate biochemical cofactors. In the case of holes in the macula or the onset of retinal detachment, scar formation can be used to fasten the retina to the layer of the eyeball lying underneath it, the choroid membrane.

"In addition to refractive correction of the cornea by laser surgery and to laser coagulation, there are laser-assisted methods for therapy of the eye lens. For example, WO 01/13838 A1 and WO 2005/070358 A1 describe the treatment of presbyopia by means of fs lasers. In this, the hardened lens is restored by suitable laser incisions or photodisruption blister fields to a state of better deformability by the capsular bag or the ciliary muscle. In principle the accommodative capacity of the lens can thus be partially regenerated.

"In cataract surgery, i.e. the replacement of the clouded eye lens by an artificial intraocular lens (IOL), what is known as phacoemulsification is established as a standard method for complete removal of the pathologically cloudy lens. In this context, the capsular bag surrounding the lens and comprising an anterior and a posterior membrane is cut open (capulorhexis) from the front (anterior). The lens is then emulsified with the aid of an ultrasonic handpiece to be introduced into the lens and moved in the lens, in order subsequently to be able to remove the lens material by suction. Methods based on Er:YAG and Nd:YAG lasers are also known, for example from WO 00/27325 A1, wherein the lens is broken up with the aid of low-frequency (10-100 Hz) laser ablations or laser-induced acoustic shock waves into segments which are easier to remove by suction These ultrasound or laser methods are invasive and can only be used during a conventional surgical intervention on the opened eye.

"Significantly less invasive is a method which is described, for example, in WO 2009/059251 A2, wherein both the capsulorhexis incision opening up the anterior of the capsular bag and the fragmentation of the lens are carried out by means of an fs laser navigated by means of optical coherence tomography. In the method described in US 2009/137993 A, the access opening in the cornea is additionally also cut by means of the fs laser.

"What is known as aftercataract typically occurs as a side effect of cataract surgery. It is a posterior capsule opacity (PCO), which develops after a cataract operation due to a proliferation of epithelial cells remaining in the capsular bag (lens epithelial cell, LEC). For treatment of aftercataract, what is known as aftercataract capsulotomy with a Q-switched Nd:YAG laser has hitherto been the method of choice. In this case, the laser beam is focussed behind the posterior capsular bag membrane and photodisruption is generated, the pressure wave of which tears the posterior capsular bag peripherally. The optically cloudy posterior membrane is removed from the optical zone of the eye by several shots, so that the patient's vision is no longer impaired.

"This destruction of the posterior capsular bag membrane can be accepted with many standard IOLs, but involves risks: In view of the mechanical stability of the eye, prolapse of the vitreous body may occur due to the destroyed capsular bag; the pressure waves during a posterior YAG laser capsulotomy may increase the probability of retinal detachment.

"In view of new approaches to cataract surgery, for example the refilling of the lens capsule with gelatinous synthetic lens material described inter alia in US 2009/076602 A1, in order to re-establish a certain accommodation of the eye, an intact capsular bag is required. Posterior capsulotomy is a disadvantage in this respect. Aftercataract capsulotomy can moreover present problems because the laser radiation is applied through the implanted IOL, which may thereby become damaged. There are therefore different approaches for preventing the development of aftercataract.

"One possibility for preventing aftercataract is known in particular from paediatric surgery and involves the surgical opening of the posterior capsular bag membrane. The surgical intervention is carried out from the vitreous body chamber in connection with a (at least partial) pars plana vitrectomy and is therefore too involved and associated with too many complications for normal cataract operations. In particular, the reduced stability of an opened posterior capsular bag membrane can lead to a vitreous body prolapse.

"To prevent aftercataract it is moreover known, for example from IN 01996MU2006 A, to kill or suppress the growth of LECs medicinally. This can be effected, for example, by flushing the capsular bag during cataract surgery. The outlay for flushing or for introduction of the medicaments is a disadvantage in this case. An addition or alternative to this are specially shaped intraocular lenses with sharp edges, which likewise impede the growth of the epithelial cells. Such IOLs are described, for example, in US 2007/027539 A1. The limitations in designing the lens shape due to the specified sharp edges are a disadvantage of this.

"A further known possibility for prophylaxis of aftercataract is to generate shock waves intraoperatively, after removal of the old lens body and before insertion of a replacement lens, by means of a metal body to be inserted into the capsular bag and irradiated with an Nd:YAG laser. In this context the beam guide equipment for the laser radiation, like the metal body, must be inserted in the form of a probe into the eye and into the capsular bag and placed manually in the immediate vicinity in front of the epithelial cell layer. The shock waves lead to a detachment of the LEC layer from the capsular bag, so that the epithelial cells can be removed by suction. The probability of the occurrence of PCO thereby decreases. As a disadvantage, however, this method requires a separate work step, which must be performed manually with great care and skill, and additional equipment."

In addition to obtaining background information on this patent application, VerticalNews editors also obtained the inventors' summary information for this patent application: "In an embodiment, the present invention provides an ophthalmologic laser device including a pulsed laser configured to produce radiation focused along at treatment beam path. A variably adjustable beam deflector unit and a focusing lens system are disposed in the treatment beam path. The deflector unit is configured to focus the radiation in different target volumes. Measuring equipment is configured to determine a shape and position of optical interfaces along a detection beam path. A control unit is configured to control the laser and the deflector unit and to implement steps including determining a shape and position of at least one interface of a membrane of a capsular bag of an eye located in a treatment area using the measuring equipment, determining coordinates of a target volume such that, on irradiation of the target volume with a laser pulse of predetermined pulse energy, a pressure wave runs from the target volume at least up to the anterior or posterior membrane without tearing the respective membrane, and adjusting the deflector unit to the target determined volume so as to irradiate the target volume with at least one laser pulse of the predetermined pulse energy using the laser.

"In an embodiment, the present invention also provides an ophthalmologic laser device including an ultra-short pulse laser configured to produce radiation focused along a treatment beam path. A variably adjustable beam deflector unit and a focusing lens system are disposed in the treatment beam path. The deflector unit is configured to focus the radiation in different target volumes. Measuring equipment is configured to determine a shape and position of optical interfaces along a detection beam path. A control unit is configured to control the laser and the deflector unit and to implement steps including determining a shape and position of at least one interface of an anterior membrane of a capsular bag of an eye located in a treatment area using the measuring equipment, determining coordinates of several target volumes where each target volume lies at least partially in the anterior membrane such that, on irradiation of the target volume with a laser pulse of predetermined pulse energy, a border of a region of the anterior membrane is perforated photodisruptively, where the region lies away from a visual axis penetration zone of the anterior membrane, and adjusting the deflector unit, respectively, to each determined target volume so as to irradiate the respective target volume with at least one laser pulse of the predetermined pulse energy using the laser.

"In another embodiment, the present invention provides an ophthalmologic laser device including an ultra-short pulse laser configured to produce radiation focused along a treatment beam path. A variably adjustable beam deflector unit and a focusing lens system are disposed in the treatment beam path. The deflector unit is configured to focus the radiation in different target volumes. Measuring equipment is configured to determine a shape and position of optical interfaces along a detection beam path. A control unit is configured to control the laser and the deflector unit and to implement steps including determining a shape and position of at least one interface of an posterior membrane of a capsular bag of an eye located in a treatment area using the measuring equipment, determining coordinates of several target volumes where each target volume lies at least partially in the posterior membrane such that, on irradiation of the target volume with a laser pulse of predetermined pulse energy, a border of a region of the posterior membrane is perforated photodisruptively, where the region border lies around a visual axis penetration zone of the posterior membrane, and adjusting the deflector unit, respectively, to each determined target volume so as to irradiate the target volume with at least one laser pulse of the predetermined pulse energy using the laser

BRIEF DESCRIPTION OF THE DRAWINGS

"The present invention will be described in even greater detail below based on the exemplary figures. The invention is not limited to the exemplary embodiments. All features described and/or illustrated herein can be used alone or combined in different combinations in embodiments of the invention. The features and advantages of various embodiments of the present invention will become apparent by reading the following detailed description with reference to the attached drawings which illustrate the following:

"FIG. 1 shows the structure of the human eye, in particular the eye lens,

"FIG. 2 shows an ophthalmologic laser device with OCT,

"FIG. 3 shows a reversible fixing device,

"FIG. 4 is a flowchart of a method for prophylaxis or treatment of PCO according to the first aspect of the invention and a resulting target volume,

"FIG. 5 is a flowchart of a method for prophylaxis of PCO according to the second aspect of the invention and resulting perforated regions,

"FIG. 6 is a flowchart of a method for prophylaxis or treatment of PCO according to the third aspect of the invention,

"FIG. 7 is a flowchart of a complete cataract operation within one laser session, including the first aspect of the invention for prophylaxis of PCO,

"FIG. 8 is a flowchart of a complete cataract operation within one laser session, including the third aspect of the invention for prophylaxis of PCO,

"FIG. 9 shows an ophthalmologic laser device with OCT and confocal detection, and

"FIG. 10 shows scanning curve for confocal measurement of interfaces in the eye.

"In all the drawings, corresponding parts carry the same reference symbols."

For more information, see this patent application: Dick, Manfred; Kuehnert, Juergen; Reich, Matthias. Ophthalmologic Laser Device and Method for Preventing and Treating Aftercataract. Filed July 26, 2012 and posted July 17, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=1327&p=27&f=G&l=50&d=PG01&S1=20140710.PD.&OS=PD/20140710&RS=PD/20140710

Keywords for this news article include: Capsulotomy, Carl Zeiss Meditec Ag, Epithelial Cells, Medical Devices, Surgery.

Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2014, NewsRx LLC


For more stories covering the world of technology, please see HispanicBusiness' Tech Channel



Source: Politics & Government Week


Story Tools






HispanicBusiness.com Facebook Linkedin Twitter RSS Feed Email Alerts & Newsletters