CA2128104A1

CA2128104A1 - Method and apparatus for transmitting laser radiation

Info

Publication number: CA2128104A1
Application number: CA002128104A
Authority: CA
Inventors: Vahid Saadatmanesh; Marvin P. Loeb; Hany M. G. Hussein
Original assignee: Individual
Current assignee: Trimedyne Inc
Priority date: 1992-01-17
Filing date: 1993-01-14
Publication date: 1993-07-22
Also published as: JPH07506733A; EP0625271A4; WO1993014430A1; EP0625271A1

Abstract

A method and device are provided for directing laser radiation in a conical beam to a tissue site to be irradiated. The conical beam can be positioned to impinge upon the tissue in a circular, elliptical, or any other pattern that can be generated by a conical section interacting with a planar or curved surface. In one form the contemplated device includes an optical fiber (20) and a lense (80) that focuses a laser beam at an oblique angle on the proximal end surface (70) of the optic fiber so as to emit from the distal end of the optical fiber (47) a laser beam having a conical configuration (99). In another form, the contemplated device includes an optical fiber (200) having a conical distal end (247) and a lens that focuses a laser beam on the proximal end surface (270) of the optical fiber (200) along the longitudinal axis of the fiber. The conical laser beam can be used to irradiate or sculpt tissue such as the cornea of an eye to change the refractive characteristic thereof.

Description

WO 93/14430 ~ 1 h 3 1 ~ ~ PCI'/US93/00357 "MEIHOD AND APPARATUS FOR TRANSMIITING LASER RADIATION"

TECHNICAL FIE~D
The present invention rel~tes to devices and procedures for the controlied deli~ery of laser energy through an optical fiber. Tha pr-~ent invention i~
e~pecially suit~ble for treating ~ ~ite on the ~urface of, or inside, a patient's body, w$th laser energy in a ~ng or hollow be~ configuration, with little or ~irtu~lly none of the light energy being emitted in the center of the ring or hollow be~m.

BACKGROUND OF THE INVENTION
AND
TECHNICAL PROBLEMS POSED BY THE PRIOR ART
Articulated ar~s u~ing an arrange~ent of m~rrors, opt~cal ~cro~cope~ and other devices have been developed for delivering laser energy to the ~urface of a patent's body. Flexible, optical fiber~ are used to convey laser energy in surgery to tis~ue or into ~
confined space. Fiber~ can also be adYanc~d through an artery or other body lumen or ca~ity, an endoscopic

2~ device, or a surqirally created pa~s~ge, to a selected internal treatment location. In certain m~dical application~, ~uch device include, or are incnrporated ~n, catheters ~or tran~mitting t~e radiation to internal ibody Sit~E;
~~ edical instrument~ of the above-described type may be bro~dly defined as ~iber deliv~ry fiystems.
As u~ed in thi~ ~pecification and in th~ claims, the ter~ ~fiber sy~tem" or ~sy~tem" is intended to include broadly flexible, or rigid, instruments for directing la~er energy to a target site on the body's ~urface or 212Sl~ l ~
93/l~30 p(l~ 9 an internal target through ~ n~tural or surgically ~reated internal lumen, passage, or ca~ity.
A lens can be used to transmit thelradiation f~om the laser into th~ optieal fiber. For example, S u.s. Paten~ N~. 4,729,621 teaches the use ofla cone-coupler having a wide proximal end fo~ receiving radiation from the laser and bavin~ a narrow ldistal end ~rhich is optically coupled to t~e input end of t~e optical fiber. The input end of the fiber is generally flat and perpendicular to the optical axis o~ the lens or coupling syste~. The laser energy is transmlt~ed :
from the lens, into the optical fiber, and is emitted :~:
f~om t~e distal end of the fi~er where it may ~e directed against the selected target site.
A number of designs have been proposed for a fiber system which can be inse ~ ed into a body passage and operated to ~irec~ the laser radiation laterally to the surrounding site: in the body cavity. While laser energy emitted from an optical fiber generally strike~
the tissue as a "spotn, beveling or changLng t~e distal surface of the optical fiber can modify the:i~pinginq energy pa~tern. Some designs employ an internally - - :
reflecting prism for d~recting the radiation latèrally.
By removing the cladding from a porti~n of ~he optical fiber, radia~ion can be t ~ tted as a generally ~60-beam r~diating outwardly fro~ the axis of the f~ber.
See, for example, U.S. Patent No~ 4,672,961, Nos.
4,852,567, and ~o. 4,7g9,479.
~ ,~iming a laser beam for use ~n surgery typical~y produces ~ spot irradiation zone ~n the target tissue. In the case of a Helium-Neon or "~eNen aiming beam:, the spo~ is red. ~s a.~esult, tissue in the spot ~ppea~s red, thus blood ~es~els within the spot csn ~e seen only poo~ly.
:35 While t~e above-discussed designs may operate WO93/14430 .~l 2 ~ PCT/US93/003~7 satisfactorily in the particular applications for which they are intended, it would be desirable to provide an improved fiber optic system for laser delivery in ophthal~ology, angioplasty, ~urgery, or even ~anufacturing wherein the laser radiation could be directed to the ~ite in a ontrolled ~anner. In particular, in ~ome application~ it would be desirable to e~it a laser beam so a~ to produce a target tissue irradiation zone having an annular, ring or hollow conical bea~ pattern.
Tt would also be advantage~u~ if such a device could be adapted for use with relatively higher power lasers in annealing the inner surfaces of tube~, cutting circles in ~aterials, and other applications in which a defined clo~ed loop, e.g., a ring, of laser energy could be ffectively e~ployed.
Preferably, such an improved de~ice is not bulky or unduly complex. It would be advantageous if a relatively 8i~pl~ and 8~11 structure could be provided for u~e as, or in, a catheter or other device to be inserted with$n a confined ~pace.
It would also be desirable to provide an improved method for irradiating sites, such as surgical sites, to effect a desired ~urface configuration of the tissue or other material at the site. The present invention provides a unique method for treating such siteQ with radiation in a controlled ~anner.
The present invention also provide~ an ! im~rovedL~ascr delivery m~thod and fiber optic delivery system suitable for coupling to a laser source to direct a bea~ of laser energy in a controlled manner to a selected site, including in the form of a hollow cone or ring of las-r n-rgy. The pr sent invention can acco~odate ~ariou- apparatu~ desiqns having the above-di~cu~cd benefits and fcatures.
-W093/~4430 PCT/US93/00357-; I U ~l ~ 4 -SUMMARY OF T~E INVENTION
The present invention can be embodied in a fiber optic system, a ~edical device or an industrial tool for applying laser energy in a controlled ~anner, including pulsed as well as continuous wave for~s, as a hollow bea~ o~ radiant energy to a ~elected site. The present in~ention can also be e~bodied in a method of so applying ~uch energy.
In accordance with one aspect of the imention, a ~a~ority of the laser energy transmitted along one or ~ore optical fibers i~ e~itted or dispensed at the distal end of the optical fiber or fibers as a hollow cone or cylinder to for~ a la~er energy ring at a plane substantially perpendicular to the longitudinal lS axis of the optical fiber at the distal end thereof. By changing t~e angle of inclination of the bea~ axis relative to the incident surface, rad~ation patterns res~bling various conical sections, e.g., oval, parabolic, hyperbolic, d liptical, or circular, can be readily generatQd. By ~oving the di~tal end of the fiber syste~ closer or further away from the target site, the size of the irradiated region can be changed at will. In thi~anner, la~er energy ~ay be applied in a precise and controlled manner to the gite for performing medical procedures. Thus, the present invention is eminently well cuited for ~culpting the surface of a cornea to a desired smooth contour, among other things.
Dne preferred form of the apparatus of this invent~on e~ploys an elongated, la~er energy trans~itting conduit in the form of a solid, cylindrical optical fiber. The fiber has a proximal end portion extending along a longitudinal axi~. A bea~ of laser energy i~ping ~ on the~prox~al end surface of the fiber at àn oblique angle. The proxi~al en1 portion of the ~093/14430 ~ PCT/US93/00357 fiber usually includes a beveled, proxi~al end surface oriented at an oblique angle relative to the proximal end longitudinal axis for receiving the laser radiation, preferably an angle of 30 to 60, and most preferably about 45. The fiber has a distal end portion di~po~ed ad~acent the site to be treated (which ~ay be in a confined gpace, e.g., a lu~en or cavity) and ha~ a distal end surface for emitting the laser radiation.
A focu~ing lens is provided with a ~ounting ~eans for holding the l~n~ and the fiber proximal end portion in a particular alignment. The optic axis of the len~ is either generally parallel to, or coincident with, the proxi~al end longitudinal axis of the fiber, and the lens is focused on the fiber proximaI end surface. A suitable la~er energy source, emitting laser energy in a pul~ed or continuou~ wave ~ode, i~ coupled to the len~. The laser radiation pas~ing through the l~ns is tra D itted into the fiber, reflected internally along the circu~ference of the fiber, and is e~itted fro~ the fiber di~tal end ~urface in a ~ub~tantially hollow cone configuration which can be advantageously e~ployed at ~elected ~ites, whether such sites are free of liquid or not.
one method aspect of this invention contemplates the po~itioning of a distal end portion of a cylindrical, solid, optical fiber opposite a target ti~sue on the surface of a patient or in a confined space. The proximal end portion of the fiber is ' provide~ith a beveled end ~urface oriented at an iangle, relative to the proximal end longitudinal axis, for receiving the laser radiation. The radiation is focus-d on th~ beveled proxi~al end ~urface through a focu~in~ len~ th~t 1~ pos~itioned relative to the proxi-~l end ~urface with the optic axi~ of the lenQ
ori-nt-d gen rally parallel to th~ proxi~al end '" , -.

~93/1~3~ PCT~US~31003~, ;
- 6 - 1 , longitudinal axis so that the laser radiatidn passing .
through the lens is trans~itted into the fiber, reflected in~ernally along the circumference of the fiber, and emitted from t~e fiber distal end surface in -:
S a substantially hollow cone configuration at a selected site. In this manner, coagulation, ablation, or ~aporization, as well as cutting in a circu~ar:
configuration can be effectively performed ~t the site. ~
~he optical f iber can also be mo~ed to reduce or increase the ~ize of the emitted ~diatidn ~attern.
Further, tissue or tissues ~an be shaped or sculpted by emitting the laser energy ~t various energy le~els for .
: predetermined perio~s of ti~e at selected and~or varylng distances from the target tissue.
A furtner aspect of the inventi~n inYolves light e~nergy at a wavelength which cannot be or is poorly transmitted through conventional optieal fiber :~
and entails a means for caUsing a laser to emit light energy in a ring-~ike, or hollow cone, beam wh~ch is conduct~d through a pat~-defining means to t~e'target site. The path-defining means may include a microscope-like device with mir~ors, or an art~culated arm wit~
mirrors, for changing the direct~on of the rad~ation relative to the direc~ion of ~ lssion from the laser.
2s S~ch laser emission is generally referred to as a TEM~.
beam ~ode.
A further aspect of the invention a~:commodates variati~v of the radiation intensity with respect to circumferential or àngular locations on the r~ng. Owing to material imperfections, manufacturing tol~rances, operational variations, and the like, the intensity of the radiation at one angular location on the tàrget ring pattern may be more or less than at another.location on t~e ring. Tn order to provide a substantiaIly uni~orm, average radiation int~n~ity, o~er a period of ~ime, for - , .

WO93/1~30 ,~ PCT/US93/00357 any location in the ring, mean~ are provided for angularly displacing at least a portion of the length of the optical fiber about it~ longitudinal axis. This can include unidirectional or reciprocal rotation or oscillation. In one presently contemplated embodiment, a circu~ferential gear is ~ounted around the fiber, and a ~all driving gear is engaged with the circumferential gear. The sJall gear ~ay be unidirectionally or reciprocally rotated, or the ~all gear ~ay be oval or elliptical in shape 80 as to oscillate the fiber about its longitudinal axi~.
The angular displace~ent of a optical fiber can be employed with other optical fiber systems that produce a hollow cone or ring of radiant laser energy.
For exa~ple, the proxi~al end portion of an optical fiber D y define a proxi~al end surface oriented 80 that it i~ sub~tantially perpendicular to the proximal end longitudinal axis. Laser radiation can be directed at an oblique angle into the proximal end ~urface of the optical fiber such that the radiation pa~sing into the optical fiber ~trikes the cylindrical wall of the fiber with an angle of incidence greater than the critical angle for total internal reflection. The laser radiation pa~sing into the optical fiber is reflected internally along the circumference of the fiber and is emitted from the fiber di~tal end surface in a substantially holl~w cone configuration. The angular di~placement of at lea~t a portion of the length of the i optical ~iber will serve to reduce circumferential - ~va`riati~n~ in the ~pat~al radiat~on pattern of the ring-like beam along it~ radial path.
Still another a~pect of the present invention e~ploy~ a ~odification of the distal end of an optical ~iber which ~ay have a proxi~al end surface normal to

3~ the longitudinal axi~ for recei~ing la~er radiation wos3/1443o PCT/US93/00357 I V~ 8 -directed along the axi~ to tbe proximal end surface. In particular, the di~t~l end of the optical fiber from which the radiation is emitted i~ ~ubstantially conical.
Preferably, the di~tal end has a right cone configuration, and the radiation is emitted in a ~ollow bea~, defining a ~halo~ on an incident surf~ce. Again, angular di~placement of the fiber may be e~ployed to eliminate variations in radiation inten~ity around the bea~.
Another form of the present invention conte~plate~ ~ unique process and ~ystem for controlling the application of radiation to a ~elected site. In particular, la~er radiation is directed from a di~tal end portion of an optical fiber to irradiate the site with a hollow conica} radiation bea~ or with an annular, substantially cylindrical radiation bea~. The distance between the fiber distal end ~urface and the material is deter-ined. Then the radiation intensity and duration is auto~atically ad~u~ted in re~pon~e to the distance deter~ination. The ~aterial at the ~ite is sculpted with the be~m by ~oving the fiber di~tal end laterally and/or axially a~ desired.
The di~tal end portion of the fiber can also be tilted relative to the ~urface of the material to define a generally oval or elliptical irradiation pattern on the material, or any other pattern approximating a conical ~ection or a portion thereof.
Another aspect of the method include~ the step ! i of po~iti,oning a di~tal end portion of at lea~t one -optical ~iber ad~acent to a target site. The distal end portion of the fiber ba~ a distal end ~urface for e~itting tbe laser radiation in the ~icinity of the site. Laser radiation i8 directed into the optical fiber. The optic~l fiber di~tal end portion is moved ad~acent the surf~ce of the ~aterial at the ~ite in ~, , WO93/14430 ~ D PCT/US93/003s7 $
_ g _ directions generally laterally of the e~itted radiation.
At least one of the following ~teps is effected in respon~e to at least one of the other of the following steps: (1) controlling the intensity of the laser radiation, (2) controlling the di~tance of the fiber distal end ~urface from the material, (3) controlling the period of time during which the material i~
irradiated with laser radiation, and (4) controlIing the angle of the fiber di~tal end surface relative to the surface of the material.
The~e controlled step~ can be effected with radiation supplied in a variety of beam ~hapes or configuration~ (e.g., ~olid cyl~ndrical or ring-like) from a variety of types of optical fibers (e.g., (a) a single, ~olid, optical fiber, (b) a single, hollow, optical fiber, (c) a plurality of solid, optical f~bers arranged in an annular bundle, (d) a fiber or plurality of fiber~ having an angled nd for emitting radiation, or ~e) one or nore optical fiber~ at who~e aistal end a ~ection of hollow optical fiber i8 pofiitioned, the section of ~ollow optical fiber being sufficiently long ~to obtain a generally uniform hollow beam or ring emission of laser energy from the distal ~urface thereof.) The laser beam emitting di~tal end of the fiber optic c~n be manipulated by mechanical means. The emitted beam can be manipulated by mirror ~ystems, or the like.
Numerou~ other ad~antage~ and features of the pre~ent i~vention will become readily apparent from the -ioliowing detailed de~cription of the invention, from the claims, and from the accompanying drawings.

~RIEF DESCRIPTION OF ~HE DRAWINGS
In tbe acco~panying drawings that for~ part of tbe specification, and in which like nu~erals are .. , . . . . . . .. , . _, . . . . , ... .. ~ .. ... . . ... ... ....... .. . .. .. . .. . ... . . . ..
... . . . . .

3/1~430 h 1 2 ~10 ~ PC1~1'593~0133:~7 - 10 - , employed to designate li}ce part~ throughout the same, FIG. 1 is a fragmentary, side elevational Yiew, partly in ~ross, section, ~howing the dlstal end portion of a laser ~eli~e~y device embodying~the~present , ~nvention;
FIG. 2 is a cross-sectional vie~ taken generally along the plane 2-2 in FIG. l;
FIG. 3 is a reproduction o~ a develope,d photographic paper image of a plurality of ring-like irradiation p~tterns, such as halo R illustrate~ in ~IG
2:
FIG. 4 is a reproduction similar to FIG. 3 but showing the resulting irradiation patterns when the . optical fiber distal end portion is til~ed so as to create an ellipti~al ring conf iguration;
FIG. 5 is a fragmentary, diagra~matic, and partially schematic side elevational view of an alternate ~hodiment of an optical fiber ~odying the present invention; and FIG. 6 is a diagramma~i~, partialIy c~ross-sect~ional view of another ~odified fonn of the present inventlon~ I -!
~:)ESCRIPTIO~ OF ~1~; PR~:FERRED ~MB8D ~
~5 The appara~us of the present in~en~ion is embodied in ~ lase~ delivery devi~e ~ich, in one prefer~ed form, can be ad~anta~eously employed f~r applying radiant laser energy in a ring-like pat~ern to a selec~ed body site, e.g., the cornea of an eyè, in an efficient manner that ~inimizes trauma adjacent to the site. Such 2 device can be operated to irradia~e a body site o~ other target with a hollow beam of laser energy of a desired shape and ~ntensity in a controlled manner : so as to minimize the likelihood of damage to adjacent tissue while effecting the desired a~lation, , :, , wog3/l44~ ~ 1 2 S 1 0 l~ PCT/US93/003S7 coagulation, cutting, or the like. The device is particularly suitable for use in the fields of ophthalmology, angioplasty, urology, and gynecology, for ex~ple.
The device, which can be designed~~to illuminate the target s~te with low powered laser energy in a ring-shaped pattern, for example, using a helium neon or HeNe laser, h~s ~any application~ in surgery.
The generated hollow laser beam can also be used in a variety of manufacturing or industrial procedures for cutting, annealing, etc., While this invention is susceptible of e~bodi~ent in many different forms, this specification and the accompanying drawings disclose only one specific lS for~ a~ an ex~ple of the invention. The invention is not intended to be limited to the embodiment so de~cribed, ~owever. The scope of the invention is pointed out in the appended clai~fi.
The apparatus of thi8 invention ~ay be e~p~oyed with suitable conventional la~er sources and coupling syste~ therefor, the details of which, although not fully illustrated or described, will be appar nt to those having skill in the art and an understanding of the necessary functions of such devices. The detailed descriptions of such devices are not necessary to an under~tanding of the invention and are not herein presented because such device form no part of the present invention.
, , IReferring now to FIG. 1, the apparatus of the present invent~on entails a lens for focusing laser energy from a laser (not fully shown) into ~he proximal, beveled end of an optical fiber, the distal end of which i~ positionQd opposite a target ti~sue on the surface of a body or within a body lu~en or cavity or in a surgi¢ally created area or passa~e. Tn so~e W093/14430 PCT/US93/~3s7 ~

'~ 1 2 '~

applications, such a fiber ~ystem ~ay be inserted through an endoscope, cannula, hollow needle, or other surgical instrument (not illustrated). The cavity into which the fiber syste~ 10 ~ay be in~erted could be a natural or surgically created lu~en, cavity or passage in body tissue. For exa~ple, the tissue ~ay define a lumen or other cavity in the body or organ. A
surgically created passage or area could be produced by a needle, by a ~calpel in abdo~inal surgery, in an open procedure or by a trocar in a laparo~copic procedure.
Typically, the cavity into which the catheter i8 inserted, or the surface tissue at which the laser energy is directed, aay be characterized as defining a body site containing a material which is to be altered by appllcation of laser radiant energy. The material may be a part of the tis~ue oer se or ~ay be an altered for~ of the tissue, ~UCh as cancerous tissue. The ~aterial could also be an additional depo~it on the ti~ue. For exa~ple, such a deposit may be a clot, fat, or arterio~clerotic plaque.
The fiber sy~te~ 10 includes an optical fiber 20 which functions as an elongated, laser energy trans~itting conduit. The optical fiber 20 is adapted to be coupled at it~ proxi~al end to a focusing lens and ~ounting fra~e or assembly 22 which in turn is coupled to a laser energy source 26 that generate~ and ~upplies radiant laser energy to the ~iber 20.
The terms "la~er energyn, "la~er radiationn, ~laser beam,~ and variants thereof a~ used in t~is spec~fication disclo~ure and in the clai~s will be under~tood to enco~pass a broad range of radiation ~odes, pulsed or continuous wave (cw), as well as frequencie~, characteri~tic~, and energy densities or fluxes.
The laser radiation ~ay be suitably produced -~40 93/14430 ~ ~ ~ 8 ~ ~t 1- ` PCT/US93/~357~

~y a conventional laser and may include infrored radiation (IR) and ultraviolet radiation (W), a~ well ~8 vi~ible la~er light. Ex~mple~ of laser types that can produce ~uitable energies include: excimer, argon, S neody~iu~:yttriu~ alu~inu~ garnQt (Nd: YAG), freguency-doubled Nd:YAG (KTP la~er), hol~iu~:yttrium alu~in~m garnet (Hol~ium:YAG) and erbiu~:yttrium aluminum garnet (Erbiu~:YAG), and the like. Likewi~e, laser energy e~itted in the ~o-call-d tronsver~e electromagnetic wave (TEM) mode can be utilized. Particularly well suited is the cylindrical TENb1. ~ode ~ade up of two TEMb~ modes, as well as the TEM~ mode and the TEM~ mode.
Conventional ~eans (not illustrated in detail) ~ay be employed for injecting the radiant laser energy to the a~senbly 22. Such ~eans usually constitutes a coupling ~ystem between the la~er ~ource 26 and the ~se~bly 22. The design, construction, and operation of la~er ~ources and coupling ~ysto~s arc well known in the art and are not de~cribed ln detail herein. The details of the de~ign, con~truction, and operation of ~uch la~er ~ources and coupling ~y~te-~ for~ no part of the present invention.
The fiber 20 i8 a single, solid, elongate, unitary, optical fiber ha~ing a cylindrical core 30 --which ~ay be ~ade of glas~ or silica quartz. In certain eDbodiment~, such fiber~ can have a high hydroxy (OH) content, for tran~mi~ion of excimer laser energy, or a low OH content, for tsan~ sion of Holmium:YAG laser energy.
In another e~bodiment, fibers of zirconiu~
fluoride, sapphire or other crystals can be used to trans~it erbium:yttrium alu~inum garnet tErbium:YAG) radiation or other infra-red wa~elengths of light.
Alternatively, in ~o~e applications, the fiber core 30 ~ay be formed from poly~eric ~aterials such as, for 0 ~
W093~1~30 '~C~ S93/003 - 14 - , example, poly(methylmethacrylate) o~ polystyrene. The diameter o~ th~ oore is preferably be~een ,a~out O.l mm.
and about l~O mm. ~n one contemplated em~odlment o~: the present inventi~n~ the diameter o~ the cor~ 30 is S prefera~ly in the range of about O 3 mm to about O.6 mm.
In a preferred ~hodiment, an o~ter cladding 34 is disposed to co~er the outer cylindrical surface the core 30. The cladding ma~erial has a refractive index wh~ch is lower than the ref~active index of the fiber cor~ 30 The material employed for the cor~ outer cladding 34 is selected on the bas~s of the refrac~i~e index relative to the co~e ref~a~tive index such tha~ -the laser radia~ion is ~onfined within the f~bex core with a minimum atte~uation Examples o~ sui~ble cladaing materials include silicone, silica, ~lass, plastic, or air.
Plastic material suitable for cladding includes polymethylmetha~rylate or a mixture of po~ymethylmethacrylate and polystyrene. The thlckness o~ the cladding 34 may ~e about 0~1 mm, for example. In one contemplated emb~di~en~, the claddin~ 3~ is air.
various opti~al ~ibers that m~y ~e suita~le for particular applications are ~o~mer~ially available.
For example, a fi~er op~i~ havinq a core diame~er o~ 0.4 mm i~ mar~eted under the designation Med 4ao by Quart2 Produ~ts ~orporation of Plainficld, ~w J~rscy. A 0.6 mm diam~ter f~ber op~ic is c~mmercially available under ~he design~tion ~CT ~00 ~rom Ensign Bickford Co., Connecti~ut, U.S.A.
The power that can ~e transmitted alonq optical f~be~ ~aries ~ith the size of the fibe~.
Utilizing the above-descri~d ~CT 600 fiber op~ic a medic~l de~ice em~dying this in~enti~n can ~ransmit as much as about 60 ~atts continuous power from:a Nd:YAG
laser source.
I

WO g3/14430 2 1 2 ~ 1 ~ 1 PCT/US93/~357 Although not nece~sary in all applications, a protective sheath (not illu~trated) may be disposed around the outer cladding 34. The ~heath may be, for example, polyethylene or a polya~ide with aj~icknes~ of about 0.2 ~.
Finally, in so~e applications it may be desirable to include an outer tubular covering (not illustrated)~ inste~d of, or in addition to, the sheath.
The covering may be a synthetic resin polymer such as the polymer sold under the trademark TEFLON. Other materials that may be used for the covering include silicone rubber, natural rubber, polyvinyl chlorides, polyurethane, copolyester polymers, ther~oplastic rubbers, silicone-polycarbonate copolymers, polyethylene ethyl-vinyl-ac~tate copoly~ers, woven polyester fibers, or co-binations of these.
The wall of the fiber sy~tem 10 m~y be reinforced. Further, radiopacity can be obtained by incorporatinq lead or barium salts into the wall of the catheter.
The fiber 20 ha~ a distal end portion 42 extending along a distal end longitudinal axis 46. The distal end of the fiber 20 has a generally planar surface 47 that i8 perpendicular to the axis 46 and that Z5 functions to emit the la~er radiation. If desired, the distal end port~on 42 ~ay be received in a rounded tubular sapphire, gla88, quartz or Pyrex cap (not ~llustrated) that i~ 6u~stantially transparent to the radiation.
The laser radiation is transmitted into the fiber 20 at the prox~mal end of the fiber which is retained in the focusing len~ and mounting assembly 22.
The assembly 22 defines a bore ~8 for receiving the proxi~al end of the fiber 20. The assembly 22 may be fabricated from a ~uitable ~aterial, ~uch as stainless wos3/1~30 PCT/VS93/00357~

~ 1 2 ~ 16 -steel or a polymeric material. The fiber 20 may be retained within the bore 68 by a s~itable friction fit or by so~e other fastening ~ean~, such as,.for example, adhesive or the like.
The proximal end of the fiber 20 i~
characterized as defining a proximal end longitudinal axi~ 66. The proxi~al end portion.of the fiber 20 defines a beveled proxi~al end ~urface 70 which is oriented at an obligue ~ngle A relative to the longitudinal axis 66.
A focusing lens 80 is held within the assembly 22 generally axially adjacent the anqled surface 70. To tbis end, the a~embly 22 includes an annular channel 82 for receiving the lens 80, and the annular channel B2 open~ to a fru~toconical pa~age 84 which i~ axially aligned with, ~nd communicate~ with, the ~ore 68. A
retaining claJp, ring, or 6eal 88 i~ preferably provided on one ~ide of the len~ 80 to help retain the lens 80 in po~ition.
The len~ 80 ~ay be a ~uitable conventional focusing len~ which i~ bounded by two refract~ng surface~ oriented about a co~oon optic axi~. The lens optic axi~ i~ either parallel to, or coincident with, the fiber proxifflal end axis 66. The axi~ 66 and the coincident optic axi~ of the len~ 80 may be characterized as being oriented at an acute angle B
relative to a plane N that is normal to the end ~urface 70.
I The lens 86 functions to focus the laser radiation a~ ~chematically illu~trated in F~G. 1 by the converging rays 9~. The radiation incident on the beveled ~urface 70 i~ refràcted generally toward the fiber exterior surface or cladding 34 on the circuoference of the fiber 20 in accordance with the 35~ well-known principles of plane ~urface refraction and ~ g3/14430 ~ 1 2 ~ 1 ~ '1 PCT/US93/~357 total internal reflection Specifically, where the medium adjacent the beveled surf~ce 70 (between the ~urface 70 and lens 80) is air (or so~e other ~ediu~ having a ~allçr ind~ex of refraction than the optical fiber core 30), the angle of refraction at the surface 70 within the core 30 is le~s than the angle of incidence, and a radiation ray passing through the ~urf~ce 70 ~8 bent toward the plane N that i~ perpendicular to the ~urface 70 Further, in the core 30, the radiation striking the cladding 34 with an angle of incidence greater than the critical angle will be transmitted by ~ultiple, total internal reflections along the length of the fiber 20 The nu~erical aperture (i e , the product of the index of refraction of the ~edium adjacent the surface 70 and the ~ine of one half of the acceptance cone angle) is equivalent of the ~guare root of the difference b~tw en the ~quare of the index of refraction of the core 30 and the quare of the index of refraction of th cladding 34 Thi~ specifie~ the ~aximu~ angle within which the light i8 acceptQd lnto and conducted through the fiber 20 Of course, a ~kew ray of the radlation ~triking the cladding 34 within the fiber 20 wili have a greater angle of incidence than the ~eridional r~ys, and the nu~erical aperture for such a ~kew ray i~ larger than that for ~eridional ray~ A
range of acceptance angle~ between about 30 and about 60 i8 desir~ble; a 45 angle approache~ optimum ! i It will be appreciated that the use of the novel bevel configuration on the fiber 20 permits the laser energy to be launch-d into the fiber to permit a ~eridional angle filling of the fiber without the need for any off-axi~ launching of th~ laser energy A~ d-scrib d above, the proxi~al end portion of the fiber 20, a~e~bly 22, and len~ 80 function 31 ~ 1 ') " , 3 3 .~ I P I ~ I P~:~ I: H [~ S

WO ~3/1*~30 . ~ ~ ~ S ~ PC;I/~:S93/003 together in combination as an intermediate "coupling meansn for tr~sferring the la~er energy frdm.the laser source 26 to the fi~er 20. 5he radiation emerges from the fiber distal end surface 47 as a hollow,cone which is sclle~a~ically illustra~ed in FIG. 1 }:y the rays 94.
An Lmaginary plane P oriented norm~l to ~he dis~al end longitudinal axis 46 ~ould be inte~sected ~y the hollow cone of rays 94 to define a ring-like irradl~tion pattern or halo R ~s ~own ~n FIG 2.
The radiation p~ttern ~ can ~e employed on the sur~ace of a body or within a ~ody lumen, ~a~ity or surgically created passage, to subject the tissue forward of t~e fiber 20 ~o a circumferential hollow beam of energy. This can be therape~tically useful in lS ophtha1mology, angiop1asty, urology, gynecology, etc., and can al~o be useful as an aLming beam in sur~e~y.
The device 10 may also ~e incorporated in a tool useful in manufacturing proce~ses for annealing the inside of t~es, cutting circle~, and the like.
FIG. 3 is a reprodu~tion of images generated on a sheet of expo~ed photographic paper which was - - ~
subje~ted to a number o~ sepa~te, ~oll~w, c~ni~a1 beams, e.g., pu1ses o~ radiation (su~h ~s illustra~ed ~y rays 94 in FIG. 1). FIG. 3 sho~s a plurality of patterns R which each correspond substantially,to the irradiation patte~n R illùstra~ed in FIG~ 2. Eac~
pattern R was produ~ed by aiming an optica1 fiber, such ~ ~
as the ~ptical fi~er 20 i11~strated in FIG. 1, at the developed photographic paper sold in ~nited StatPs of America under the designation ZAP-ITTU ~y Kentec Corporation, 4 Depot S~reet, Pittsfield, NH 032~3 ~.S.A.
The laser radiation ~a5 produced with a ho1mium:yttrium alum~num garnet laser operating at a waYelengt~ of 2.1 mi~rons and generating 200 mi11ijou1es at 5 p~lses per se~ond transmitted through an optical ~14g3/14430 2 1 2 ~ ~ O ~ PCT/US93/00357 fiber having a diaaeter of about 400 microns with a proximal end ~urface defining about a 60 bevel (corresponding end surface 70 in FIG 1 wherein the angle B is about 60) ~ ~
S As the radiation-~itting distal énd of the optical fiber was ~o~ed closer to the-exposed photographic paper (analoqous to ~oving the fiber end 47 closer to the plane P lllustrated in FIG 1), the dia~eter of the ring pattern decreased Eventually, the pattern ceased to display a discernible, non-irradiated, circular, center region so that the irradiation pattern appeared to be a generally solid, circular pattern indicated by the reference letter S in FIG 3 The di tal end of the optical fiber can be tilted relative to the plane of the target ~ite For exa~ple, and with reference to FIG 1, the distal end ~urface 47 can be oriented at an oblique angle relative to the plane P Thi~ produce~ a generally elliptical ring configur~tion with a gr ater energy density or flux oc~lrring at tho~e portion~ of the pattern on the target ~ite which are closest to the angled emission surface FIG 4 illustrates such elliptical configurations of the irradiation pattern ~IG 4 is a reproduction of the expo~ed ZAP-ITTM brand papes described above which has been subjected to la~er radiation from the above-described holmiuo yttrium aluminu~ garnet la~er The radiation-e~itting end ~urface of tbe optical fiber wa~ tilted at an oblique angle to the plane of the photographic paper to produce the elliptical, ring patterns designated by the reference letter E
Accordin~ to anoth r a~pect of the invention, th- conic~l bea~ can be e~itted directly fro~ the laser, which i~ po~itioned opposite the target and the WO93/1~30 PCT/USg3/00357,~
- ~12~10~ - 20 -direction of the conical bea~ from the dist_l end of the fiber can be altered by conducting it through a path defining ~eans, such a~ a ~icro~cope-like device with mirror~ or an articulated ar~ w~th mirrors,~a~ known S in the art. This i~ particularly desirable in the case of certain lasers e~itting light energy at a wavelength which is difficult or i~po~sible to transmit through convention~l optical fiber~, such a~ the argon fluoride (exci~er) la~er, the erbiu~:YAG laser, the C0 laser, and the co~ laser, and the like.
According t~ a novel ~ethod of the pre~ent invention, the distal end portion 42 of the cylindrical optical fiber 20 i5 positioned opposite a tissue on the ~urface of the body or in a confined space with the lS di~tal end ~urface oriented for emitting the laser radiation in the ~icinity of the target or site.
The proxi~al end portion of the fiber 20 is positioned to extend along the proxi~al end longitudinal axis 66 with the b~el d nd ~urface 70 oriented at an obligue angle A relative to the axi6 66 for receiving the la~er radiation.
The radiation i6 focu6ed on the be~eled surface 70 through the focuRing lens 80 which is po~it~oned rel_ti~e to the proximal end surface 70 with the optic axi~ of the lQns 80 being oriented either generally parallel to, or coincident with, the proximal end longitudinal axis 66. The laser radiation passes through the lens 80 and is transmitted into the fiber 20 where it is refracted and reflected internally along the Circumference of the fiber until it i~ e~itted from the fiber distal end surface 47 in a substantially hollow cone configuration.
In a pr-ferr d for~ of the ~ethod, the fiber 20 i8 incorporated in a fiber syste~ which i~ ad~anced ~- 35 to the target tissue to position the di~tal end of the .

wo 93/14430 2 ~ 2 ~ 1 PCI /US93/0035?

fiber 20 positioned at a selected axial location 60 as to be able to irradiate the body site.
The fiber ~yste~ ~ay be positioned visually or with the aid of fluoro~copy or ultrasound. ~I~ some~-S treat~ent procedure~, the fib~r ~yste~ ~ay'bé advanced t~rough an endo~cope, cannula, hollow needle, or other surgical tool.
If the fiber syste~ iB inserted through an endoscope, cannula, hollow needle, or other surgical tool, then fluids may be infu~ed about the fiber system body through the ~ain pas~age in the tool or through a separate channel in the tool provided for that purpose.
The fluids can include flushing fluids or treatment fluids, ~uch as saline, a glycine solution, sorbitol-Jannitol solution, ~terile water, gases (such as carbon - dioxide), and oxygen bearing liguids. Agent~ or drugs, suoh as an anti-coagulant, anti-spasmodic, anti-va~ocon~trictive, or others, can be infused along with the ~luid. Suction could ai~o be effected thsough the - 20 ~ndo~cope or other tool.
Another aspect of the present imention relates to the p~oduction of radiation in a hollow cone oonfiguration from the end of an optical fiber having a unique shape. FIG. 5 illu~trates ~uch an optical fiber 200. The fiber 200 is a cylindrical, solid, optical fiber which include~ a proxi~al end portion defining a proximal end surface 270 and a distal end surface 247.
The fiber 200 ~ay be fabricated from the same ~aterials as de~cribed abo~e with reference to the fiber 20 illu~trated in FIG. 1. In the preferreid form, the proxi~al end ~urface 270 of the fiber 200 is oriented so that it is geinerally no D al to the proxi~al end longitudina} axi~ 266. The distal end portio~ of the fiber 200 ext-nd~ along a di~tal end longitudinal axi~
~49. When tbe fiber 200 is oriented in a ~traight, 212~1 0~
Wo 93/1~30 P<~ ;9 linear configuration, the axes 266 and ~49 ,are col 1 inear .
The distal end ~;urfacc 247 def ines ! ~t least one generally cc~nical conf iquratic~ wit:h the . base of th~
cone being oriented generally per~endicular to the distal end longitudinal ~xi~ 249. Preferably, the distal end surface ~47 define~ ~ right c:ircular cone wi~eh its vertex lying on the distal end longitudinal axis 24S~. .
Laser ~eam is directed into t~e fib~r's proximal end s~rface 270, and prefer~bly the radiation is direc~ed generally perpendicularly to t~e proxi~al end surface 27 0 ~ The laser radiation is transmi~t~d through the fiber 200 and is emitted from the conical dis~al end ~urface ~4g in a substantially hollow Gone configuration. The emitted radiation, when imp~nging upon a generally planar target surface that is normal to t~e distal end longitudinal axis 24~, defines a ' ring-li~e irradia~ion pattern or halo R. Other irradiation patterns resembling a ~onîcal sect.ion or a portion thereof are prodllced as the longitudinal axis 249 is inclined at an angle les~ than 90 degree~ relative ~o~
the tar~et surf a~e .
The laser radiation may not be a uniformly emitted in a hollow cone configur~tiorl ~rom the optic~
fiber distal end. Thi5 non-uni~ormity ~ay ~e due to manufacturing and~or asse~ly tolerances, small.
variations i n material quali~r or compo~ition, snsall variations in operating conditions, and the likc. T~us, the intensity or flux of the radiation f~ield ~ in ! the ring-}ike pattern R defined at t~e target surface (as il lustrated in FIG . 2 ) ~ay }: e non-uni f or~ wi~:h respect to angular or circumferential lo~a~ions on ~e ring pattern. ~or example, with reference to FI~i. 2, an 3~ annular por~ion or segment Z 1 of the halo pattern R may r~O~3/144~ ~ L ~ ~ 1 V ~ PCT/US93/00357 have a radiation intensity that is greater or less than the re~aining portion of the ring pattern R. There may be one or more other annular portions, ~uch ~8 region Z2, in which the radiation intensity or flux ~ould also differ from that in ot~er portion~ of the ~ng pattern R.
In many applications, and where strict ~anufacturing, assembly, and operating tolerance~ are i~posed, ~uch variations ~ay ha~e a negligible effect with respect to the particular use of the radiation.
However, depending upon general power levels, size of the ring pattern, and other factors, the angular variations in intensity of the ring pattern could be sufficiently significant so as to result in undesirably ~S unev n or non-unifor~ effects on the target ~ite tissue or other target ~aterial. ThUs, it would desirable to provide a ~e~ns for reducing, if not eli~inating, the angular (circumferential) Yariation~.
al80, where a central zone of ablation is reguir d, rather than ~oving the fiber sufficiently close to the target tissue to create a solid or complete spot, since that close proxi~ity may cause spattering of ablation byproducts and foul or damage the distal end of the fiber, it would be desirable to be able to describe a solid, central spot with a gradual lateral diminution of energy.
To this end, a novel ~ystem can be employed for providing an irradiation pattern that i6 substantiallly uniform at the center or peri~eter over a period of time. Specifically, as illustrated in FIG. 6, at least a portion of the length of an ~ptical fiber, such as an optical fiber 300, is angularly displaced about its longltudinal axis during a period of ti~e in which the rad~ation is e~itted from the fiber 300. The fiber 300 ~ay have the sa~e co~position as the fiber 20 W093/14430 PCT/US93/~357 -2 1 ~

described above with reference to FIG. 1. The fiber 300 ~ay have a proxi~al end configuration and a distal r configuration as shown for the fiber 20 in FIG. 1 or as ~hown for the fiber 200 in FIG. 5. In any ~a~e, the fiber 300 i8 arranged to cooperate with the laser radiation ~ource ~o as to effect e~ission of the laser radiation fro~ the fiber di~tal end in a ~ub~tantially hollow cone configuration.
A driven ring gear 350 i8 ~ounted to the circumference of the fiber 300 by ~uitable means (e.g., adhesive at 353). A drive gear 355 i5 engaged with the ring gear 350. The drive gear 355 i8 ~ounted on a ~haft 357. The shaft 357 is driven by ~uitable ~eans, such as a ~otor (not illustrated), to rotate the drive gear 355.
The rotation of the drive g~ar 355 effects rotation of the ring gear 350 which in turn cause~ the fiber 300 to rota*e relative to its longitudinal axis. The rotation ~ay be a ~mall angular displace~ent, and in the preferred for~, th~ anlgular di~place~ent is in the for~
of~ an o~cillation of the fiber 300 (as indicat~d by the - double headed arrow 359) as effected by the ~otor cau~ing the dri~e gear 353 to oscillate (in the direction of the double headed arrow 360). In a pre~ently conte~plated for~ of operation, the fiber 300 would be o~cillated between about O to about 360.
Further, if the laser radiation source is operated in a pul~ing ~ode, then the osc~illation~ are preferably synchronized with the laser energy pulse, and thi~ could ! be effected with an ~ppropriate stepping ~otor and a ~uitable control ~yste~ 361 which ~ay include an appropriate ~witch or switches ~ounted to a ~uitable conduit or enclosure 363 which i~olates the 350, gear 353, and ~haft 3S7 fro~ the urrounding environment.
Only a portion of the length of the optical ~; 35 fiber 300 n-ed be angularly displaced, and typically : ~ :
';:

~93/l44~ 2 1 2 ~ 1 0 'I rcT/usg3/oo357 ,~

2 5 ~ ~ r ~, only a d~stal end portion of the fiber 300 would be oscillated or otherwise angularly displaced about the di~tal end portion longitudin~l axi~ during the irradiation process S In ophthalmology, sculpting or rémodeling of the cornea ~ay be acco~plished by emitting la~er energy at a ~elected inten~ity at a predetermined di~tance from the cornea for ~ chosen period of ti~e In so~e instance~ it i~ desirable to retract, temporarily the epithelium of the cornea prior to the laser irr~diation of the anterior fiurface of the cornea By varying the radiation energy level, d~tance from the cornea, and/or period of ti~e of laser e~is~ion, it is po sible to ~ary the rate of ~blation, vaporization, or coagulation and the size and depth of the irradiation area By tilting the angle of the fiber distal end portion from a perpendicular position relative to a generally planar site, the la~er energy c~n be emitted, for example, in ~n elliptical or parabolic configuration with a relatively greater A~oune of energy den~ity and deeper ablation, ~aporization or coagulation resulting at one end of the configuration than the other 80 as to create a bifocal e~fect The di~tal end portion of the optical fiber or catheter can be moved in directions generally laterally of the emitted r~diation, either m~nually or ~echanically, and preferably by a ~echanical means directed by a computer to ~ore accurately control the ~culpting proces~ The depth of ablation or coagulation can be indic~ted by displaying the p~tent's corne~l shape on a televi~ion ~onitor ~nd, using ~ light pen, the desired pattern can bè drawn upon the ~creen When thi~ i~ done in one or ~ore planes, preferably at least two plane~, the la~-r en rgy, duration of expo~ure, and ~-~ 35- di~tance fron the cornea can be deter~ined ana the .
~ ~ .

3 1 ~ 5 1 ~ 1 1 " " ~ 3 3 .~ ~ " .S ~ l P I ~ I f'~
i . 93/14430 ~12 ~ 10 4 Pcr/~ls~3/n~

energy applied as desired. For safety purposes, the computer can conduct a "dry run" and displayithe resulting shape of the cornea, compared to the or~ginal shape.
Such procedures can be e~ployed, for example, to increase or decrease t~e cur~ature of the cornea.
Also, these techniques may be employed to merely heat a site to effect localized 6hrinkage af the surface of the cornea in ~he bhape of a ~lng or any other desi~ed configuration by collagen cross-linking.
Curvat~re of the cornea, and thus the refractive properties of the eye, can be ad justed by either s~lective remova} of corn~al tis~ue and/or by selective denaturization of t~e corneal ti~ue. Remo~al.
of the corneal tissue ~ay be effected- in a controlled manner usin~ hollow laser beam irradiation in the ultraviolet or ~nfr~red ranges in accordance with the present invention, while thermal denaturization of selected regions of t~e corneal tissue can be achiev~d using laser beam irraaiation in the near-infrared range.
In the type of present laser delivery device that generates a hollow bea~, an excime.r or er~;u~:YXG
laser can be coupled with a computer-cont~olled x-, y-, z-plane positioning system and used to change the refra~ti~e power of the corne~ by madifying i~s outer contour.
Simitarly, a thermal la~er, such as.N~:YAG, suitably pulsed and/or frequency ~ipled (3~1 ~m wavelength), holmium, erbium, or the like, again appropriately coupled with a computer-~ontrolled x-, y-, 2-plane positioning system, can be utilized t~ ~ange the corneal refractive power by cres~ing therewit~in - three-dLmensional:zones or region~ o~ thermally , denatured collaqen. These tbree-dimensional:zones or regions can bave any:desired configuration that modifies ~'Og3/144~ ~ PCT/US93/00357 the outer contour of the cornea and thu~ change~ its refractive power. The foregoing techniques can be employed singly, or in co~bination, to effect the de~ired corneal sculpting. ,~ ~ -S Al-o, for corneal ~culpting with the thermal technique the cornea can be pre-treated with certain color bodies that preferentially absorb the la~er wavelength that will be applied. For example, riboflavin dye or the patient's own erythrocyte~ can be applied to the cornea for u~e in conjunction wit~ an argon laser.
The laser energy can be delivered in a continuou~ ~ode a~ well as a pul~ed mode, a~ de~ired.
Depending upon the wavelength of the involved la~er bea~, which can be in the range of about O.I5 ~ to about 11 ~a, ablaeive photodecomposition as well as ther~al denaturization or deco~position can be effected.
Th appli d power flux can be pulsed or continuou~ for corneal sculpting and can be in range of about 1 ~oule per square centi~eter to about 10 ~oules per square centi~eter.
When operating the la~er bea~ in a pulsed ~ode, tbe energy of individual pul~e~ can vary, usually in the range of about 1 ~illi~oule to about 300 ~illi~oule6. The pulse duration can be in the range of about 10 nano~econd~ to about 400 ~icrosecond~. The depth of corneal ablation per pul~e can be in the range of about 0.1 micron to about 200 ~icrons. Excimer laser ! power flux of 1 ~oule/cm2 ablates corneal ti~ue to a depth of about 1 ~icron.
Thè distance between the optical fiber distal end ~urface and the ~aterial at tbe irradiation site can also be ~easured, as with`infra-red di~tance deter~ination techniques, sonar distance determination technique~, or other technique~. The ~easurement of the WOg3/144~ PCT/US93/~357_ distance can be input to an appropriate microproces~or or co~puter for effecting control of the inten~ity of the energy of the laser radiation, the duration of exposure of the 6ite ~aterial to the radiation, and~or S tbQ location of the optical fiber distal end portion relative to the 6it~
The above-described control techniques ~ay be applied to other optical fiber tran6~i~sion6 of laser radiation not only during ophthal~ologic procedure6 but also during medical a6 well a6 non-medical procedures Such control tQchniques need not be li~ited to u~e with the above-de6cribed solid, optical fiber which produces a hollow cone be~m for irradiating a target site with a ring-like pattern Indeed, the above-described control t~chniques ~y even be e~ployed with an optical fiber that ~ its laser radiation in a generally solid, cylindrical b~a~ that define- a spot zone on the target ti~u~
Also, in another a-pect of the ~ethod of the pre~-nt im ention, a plurality of solid, optical fiber~
(e g , ~bout 200 to about 500 having a dia~eter, for exa ple, of b~tw en about 10 ~icrons and about 50 ~icrons) ~ay be arranged in an annulas bundle, as by packing the fib~rs in the annular space between a pair of co~ncentric cylindrical d eeve6 Such a construction ~ay be employed to tr~n~it a generally ring-like be~m In addition, a sufficiently long ~ection of hollow, optical fiber ~ay be ~upplied at its proximal end with laser radiation from a solid, optical fiber0 extending from a laser in a manner ~o that the radiation itted from the distal end of the hollow, optical fiber in a ring-like bea~.
Wlth either an annular bundle of fibers or a single, hollow, optical fiber, the distal end may be 35 tilted or angled relative to the surface of the ~aterial ~D93/14430 , 1~ 2 ~ 1 PCT/US93/00357 5 ~ f at the target site so as to provide a generally elliptical, ring-like target are~ where the energy intensity may vary depending upon a selected location within the elliptical ring pattern. ,~
Also, a ~olid, optical flbes may be similarly tilted relative to the target site for producing a generally ~olid, elliptical pattern on the site.
The distal, radiation-emitting end of the above-de~cribed annular bundle of fibers c~n be arranged in an angled or beveled configuration. Similarly, the end of the hollow, optical fiber may be cut to form an angled or beveled end. When the ~urface of such a beveled end is viewed in elevation in a direction normal to the longitudinal axis of the fiber(s), then it ~ppears as an ellipse or oval ~hape.
It will be appreciated that the present i m ention provide~ a novel ~ethod and apparatus for officl-ntly controlling and directing radiation, including the tranfi~ission of radiation in a hollow cone or ring configuration, to a ~elected site which may be - located in a confined space.
In accordance with the preceding discussion, further adaption and variations of the present invention will be readily perceived by practitioners of the 2S ~edical instrumentation and ~anufacturing arts.
Therefore, the present invention ~hould be interpreted in accordance with the language of the following claims and not solely in accordance with the particular e~bodiments within which the invention has been taught.

.~
.,

Claims

WHAT IS CLAIMED IS:

1. A device for emitting laser radiation as a hollow beam, said device comprising:
a cylindrical, optical fiber having a proximal end portion extending along a proximal end longitudinal axis, said proximal end portion of said fiber including a beveled proximal end surface oriented an an oblique angle relative to said proximal end longitudinal axis for receiving said laser radiation, said fiber having a distal end portion for being disposed adjacent said site and having a distal end surface for emitting said laser radiation; and a focusing lens and mounting means for holding said lens and said fiber proximal end portion in an arrangement wherein (A) the optic axis of said lens has one of the orientations of being (1) generally parallel to said proximal end longitudinal axis and (2) coincident with said longitudinal axis, and (B) said lens is generally focused on said fiber proximal end surface so that laser radiation passing through said lens is transmitted into said fiber, reflected internally along the circumference of said fiber, and emitted from said fiber distal end surface as a beam in a substantially hollow cone configuration.

2. The device in accordance with claim 1 in which said fiber is fabricated from zirconium fluoride for transmitting said laser radiation from an erbium:yttrium aluminum garnet laser.

3. The device in accordance with claim 1 in which said fiber distal end portion extends along a distal end longitudinal axis and said fiber distal end surface is oriented generally perpendicular to said distal end longitudinal axis whereby said radiation is emitted from said fiber distal end surface in a substantially hollow cone configuration.

4. The device in accordance wit claim 1 in which said optical fiber is a solid and is elongate.

5. The device in accordance with claim 1 in which said lens optic axis is coincident with said proximal end longitudinal axis.

6. The device in accordance with claim 1 further including path defining means at said fiber distal end surface for defining at least one radiation transmission path including at least one mirror for reflecting said radiation to change the direction of said radiation relative to the direction of emission from said fiber distal end surface.

7. The device in accordance with claim 1 further including drive means for angularly displacing at least a portion of the distal end of said fiber about a longitudinal axis.

8. The device in accordance with claim 7 in which said drive means includes means for oscillating the distal end of said fiber length about said longitudinal axis.

9. The device in accordance with claim 8 in which said oscillating means includes a driven ring gear mounted to the circumference of said fiber;
a drive gear engaged with said ring gear: a shaft connected to said drive gear; and means for oscillating said shaft.

10. A device for emitting laser radiation in a hollow beam to a site, said device comprising:
a cylindrical, optical fiber having a distal end portion disposed adjacent said site for emitting said laser radiation; and coupling means integral with said fiber for transferring said radiation from a laser to the proximal end of said fiber, said coupling means including (a) a frame, (b) a proximal end portion of said fiber having a beveled proximal end surface maintained by said frame at an oblique angle relative to a selected coupling axis, and (c) a focusing lens held by said frame, said lens being held by said frame to maintain the optic axis of said lens in one of the orientations of being (1) generally parallel to said coupling axis and (2) coincident with said coupling axis, said lens being held by said frame to maintain said lens focused on said beveled proximal end surface so that laser radiation passing through said lens is transmitted into said fiber, reflected internally along the circumference of said fiber, and emitted from said fiber distal end surface as a beam in a substantially hollow cone configuration.

11. The device in accordance with claim 10 in which said fiber distal end portion extends along a distal end longitudinal axis and said fiber distal end surface is oriented generally perpendicular to said distal end longitudinal axis whereby said radiation is emitted from said fiber distal end surface in a substantially hollow cone configuration.

12. The device in accordance with claim 10 in which said fiber is fabricated from zirconium fluoride for transmitting said laser radiation from an erbium:yttrium aluminum garnet laser.

13. A device for producing a laser radiation pattern in the form of a hollow conical section at a site, said device comprising:
a cylindrical, solid, optical fiber having a proximal end portion extending along a proximal end longitudinal axis, said proximal end portion of said fiber including a proximal end surface for receiving said laser radiation directed generally perpendicularly to said proximal end surface, said fiber having a distal end portion extending along a distal and longitudinal axis for being disposed adjacent said site and having a distal end surface for emitting said laser radiation, said distal end surface defining at least one generally conical configuration with the base of the cone oriented generally perpendicularly to said distal end longitudinal axis whereby said laser radiation that is transmitted into said fiber it emitted from said fiber distal end surface in a substantially hollow cone configuration.

14. The device in accordance with claim 13 in which said proximal end surface is oriented so that it is generally normal to said proximal end longitudinal axis, and;
said distal and surface defines a right circular cone with its vertex lying on said distal and longitudinal axis;

15. A device for emitting laser radiation in a ring-like pattern to a site with substantially uniform, angular, time averaged intensity, said device comprising:
a cylindrical, optical fiber having a proximal and portion including a proximal end surface for receiving said laser radiation, said fiber having a distal end portion for being disposed adjacent said site and having a distal end surface for emitting said laser radiation;
a laser radiation source means for directing said laser radiation through said proximal and surface into said fiber for being transmitted along said fiber, said source means and fiber operating together to effect emission of said laser radiation from said fiber distal W ?3/14430 PCT/US93/00357 end surface in a substantially hollow cone configuration; and drive means for angularly displacing at least portion of the length of said fiber about longitudinal axis.

16. The device in accordance with claim 15 in which said drive means includes means for oscillating said fiber length about its longitudinal axis

17. The device in accordance with claim 16 in which said oscillating means includes a driven ring gear mounted to the circumference of said fiber;
a drive gear engaged with said ring gear;
a shaft connected to laid drive gear; and means for oscillating said shaft.

18. A method for emitting laser radiation as a hollow beam to produce a ring-like pattern at a site, said method comprising the steps of:
(a) positioning a distal end portion of a cylindrical optical fiber relative to said site with a distal end portion having a distal end surface for emitting said laser radiation in the vicinity of said site;
(b) positioning a proximal end portion of said fiber to extend along a proximal end longitudinal axis with a beveled proximal end surface of said portion oriented at an oblique angle relative to said proximal end longitudinal axis for receiving said laser radiation; and (c) focusing said radiation on said beveled proximal end surface through a focusing lens positioned relative to said proximal end surface in an arrangement wherein the optic axis of said lens has one of the orientations of being (1) generally parallel to said proximal end longitudinal axis and (2) coincident with said longitudinal axis so that laser radiation passing through said lens is transmitted into said fiber, reflected internally along the circumference of said fiber, and emitted from said fiber distal end surface in a substantially hollow cone configuration.

19. The method in accordance with claim 18 in which step (a) includes providing said fiber with said fiber distal end surface oriented generally perpendicular to said distal end longitudinal axis whereby said radiation is emitted from said fiber distal end surface in a substantially hollow cone configuration.

20. The method in accordance with claim 18 in which step (c) includes positioning said lens with said optic axis oriented coincident with said proximal end longitudinal axis.

21. The method in accordance with claim 18 in which step (a) includes providing said fiber with a core surrounded by a cladding having an index of refraction smaller than the index of refraction of said core;
step (b) includes positioning said proximal end portion with said beveled proximal end surface adjacent a medium having an index of refraction less than the index of refraction of said fiber core; and steps (b) and (c) include positioning said fiber proximal end portion so that a plane perpendicular to said beveled proximal end surface is oriented at an acute angle relative to said proximal end longitudinal axis and wherein the product of (1) the index of refraction of said medium and (2) the sine of said acute angle is less than the square root of the difference between (1) the square of the index of refraction of the fiber core and (2) the square of the index of refraction of the fiber cladding.

22. The method in accordance with claim 18 in which said method is employed to sculpt tissue, such as a cornea or the like, said method including at least one of the following steps:
(1) varying the intensity of the laser radiation, (2) varying the distance of said fiber distal end surface from said tissue, and (3) varying the period of time during which the laser radiation is emitted.

23. A method for irradiating material at a site with laser radiation, said method comprising the steps of:
(a) directing said radiation from a distal end portion of an optical fiber to irradiate said site with one of a hollow conical radiation beam and an annular cylindrical radiation beam; and (b) sculpting said material with said beam by moving said fiber distal end and effecting the steps of determining the distance between said fiber distal end surface and said material and adjusting the radiation intensity and duration in response to said distance determination.

24. The method in accordance with claim 23 in which said step of moving said fiber distal end portion includes tilting said fiber distal end portion relative to the surface of said material to define a generally elliptical ring-like irradiation pattern on said material.

25. The method for irradiating material at a site with laser radiation, said method comprising the steps of:
(a) positioning a distal end portion of at least one optical fiber relative to said site with a distal end portion of said fiber having a distal end surface for emitting said laser radiation in the vicinity of said site;
(b) directing said laser radiation into said optical fiber; and (c) moving said optical fiber distal end portion adjacent the surface of said material at said site in directions generally laterally of the emitted radiation and effecting at least one of the following steps in response to at least one of the other of the following steps:
(1) controlling the intensity of the laser radiation, (2) controlling the distance of said fiber distal end surface from said material, (3) controlling the duration of exposure of said material to said laser radiation, and (4) controlling the angle of said fiber distal end surface relative to the surface of said material.

26. The method in accordance with claim 25 in which step (b) includes measuring said distance by using one of techniques selected from the group of techniques consisting of: infra-red distance determination and sonar distance determination.

27. The method in accordance with claim 25 further including the steps of:
displaying the actual surface configuration of at least one planar cross section of said site on a video monitor;
drawing a desired surface configuration of said one planar cross section with a light pen; and effecting step (c) by controlling said movement of said optical fiber distal end portion with a computer to achieve the desired zone of laser radiation.

? 93/14430 PCT/US93/00357

28. The method in accordance with claim 25 in which step (a) includes orienting a plurality of solid optical fibers with beveled distal end surfaces in an annular bundle configuration with the distal end portions of said solid optical fibers positioned in the vicinity of said site with the beveled end surfaces oriented at an angle to the surface of said material at said site.

29. The method in accordance with claim 25 in which step (a) includes positioning a single, hollow, optical fiber with 8 beveled distal end surface oriented at an angle to the surface of said material at said site.

30. A method for shaping a cornea which method comprises:
generating a hollow beam of laser energy having a wavelength in the range of about 0.15 µm to about 11 µm; and applying at least a portion of the generated hollow beam to a selected region of the cornea and irradiating said region for a time period sufficient to change the refractive characteristic of the cornea.