CA2117753A1 - Corneal vacuum centering guide and dissector - Google Patents

Abstract

This invention is a surgical device for producing a generally circular, interlamellar pathway within the corneal stroma of the eye. The device is made up of three major components: a vacuum centering guide (50) having an inner bore (62) which fits at one end against the front of the eye, a barrel which fits within the inner bore of the centering guide and to which is attached the third major component, a generally circular dissecting ring. The dissecting ring (66) is shaped in such way that when an eye surgeon twists the barrel to which the ring is attached, the ring moves through the interlamellar space in the stroma producing the desired channel or pathway. The centering guide (62) may optionally include a ring having one or more pins which firmly engage the cornea's epiphilium. The constituent parts of the surgical device, particularly the dissecting ring, also form a part of this invention.

Description

W093/20763 PCT/US93~03214 i 2~'177~3 $~F~ a~ CENTERING GUIDE AND DISSECTOR

Field_of _he Invention This invention is a surgical device for producing a generally circular, interlamellar pathway within the corneal stroma of the eye. The device is made : up o~ three major components: a ~acuum centering guide ha~ing an inner bore which fits at one end against the front of the eye, a barrel which f its within the inner 5 bore: of the centering guide and to which is attached the third maJor component, a generally circular dissecting rin~. Th~ dissecting ring is shaped in such a way that when ~ an eye surgeon twists the barrel to which the ring is: ~atta hed, the ring mov~s through the interlamellar 20 ~ space: in the s~roma producing lthe desired channel or : pathway~ The ~centerirlg guide ~nay optionally include a :æing ha~ing one :or more pins which firmly engage the cornea ' s eplphil~ The constituea~t p~rts of the urgical device,~ particu~arly the dissec1:ins~ ring, also 2~5~ rm:~a part of :this in7vention.
A split ~ring, or intracorrleal ring (I~ICR"), is i nsert~d into the :~intrastromal pa sageway prodllced ~y the inv~ntive device~. The ICR changes the ~hape of the corn~a~ and, ~in doing so, provides~ a chos~n measure of 3 0 v isual correc~ion .
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Anomalies in the overall ~hap~ of the ey~ can cause :visual dissrders. Hyp~ropia ~"fars~ghtedrle;s") ~5 ~ occurs uhen the front-to-back disezmce in the eyeball is ~: :
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W093/2~763 PCT/U~3~03214 211~7~3 -2~
too small~ In ~uch a case, parallel rays originating greater than 20 feet from the ~ye focus behind the retina. In contrast, wh2n the front-to-back distance of eyeba}l is too large, myopia ("n~arsightedness") oocurs S and the focus of parallel rays entering th~ eye occurs in front of the retina. Astigmatism is a condition-which occurs when the pa.allel rays of light do not come to a single point within th~ eye, but rather have a variable ~ocus due to the fact that the eornea is aspherical and refracts light in a di~ferent meridian at different distances. Some degree of as igmati~m is normal, but where it is too high, it must often be corrected.
Hyperopia, myopia, and astigmatism are usually ~orrec~ed by glasses or contact lenses. Surgical methods : ~ lS for the correction of such disorder are known. Such ~ methods include radial keratotony (see, e.g., U.S.
: Patents Nos. 4,815,463 and 4,688,570) and laser corneal ablation (se , e.g., U.S~ Patent No. 4,94l,093~.
Another method for correcting those disorders 20 : is through the implantation of polymeric rings in the ~` eye's cornsal s~roma to change the curvature oi th~
: corn~a. Previous work involving the im~lanta~ion of pol~ethylmethacrylate (PM~A) ring~, allograft corneal tissue, and hydrogels is well documented. One of the 2~ ring devices învolves a ring design that allows a split ring to be inserted into a channel dis ected in the str~al l~yer o~ the cornea using a ~inîmally inva~ive inGision through whîch the channel ~or the implan~ is created and through whîch th~ i~plant i9 in~erted.
~.S. Patent No. 4,452,~35, ~o Xeyns:lds, describ2s a method and apparatus for corneal curvature adjustm~nt~ The method involves inserting one ~nd of a sp}it end adjusting ring into the cornea of the eye and : moving the ring in a circular p~th until its ends meet.
The ends are thereafter adjusted r~lative to each other ;::

WO ~3l20763 PCr/US93/0321 ~!
-3- 21177~3 unt7 1 the shape of the eye has assumed a desired curvature wher~upon th~ ends are f ixedly attac~ed to maintain the desired curvature of the cornea.
Although the procedure for introducing ICRs S into the intracorneal stroma i~ known, our inventive insertion devic:e~: used to implement these proc:edures is not shown.
Vacuum devices useful for.ocular surgical procedures are, however, common. For instance, U. S .
Pat. No. 4, 423, 728, ts Lieberman, shows a cam guided trephine for selectively cutting a circular or V-shaped groove about the cornea. The device utilizes a pair o~
suction rings which af f ix the apparatus onto the sclera of the patient ' s eye . The ~racuum is usually less than l5 about lOcm of wa~er thereby avoiding raising the ~: intrascular pressuxe above the physiological levels. The ~: suc~ion rirlg lies in the anatomically constant area just : outside the li~u~.
Similarly, lJ.S. P~t. No. 4,997,437 to 20~ Grieshaber, s~ows a process and appar~tus for cornea rinding. The ~evic~ has a ba~e member which is held to the conjunctiva :o~ the eye by ~racuum space formed ~bout the periphea~ of the cornea. A rotary grind~r is a~tached to the base me~er and slides onto the eye through the 25 ~: interior bore of the }:ase member. No pro~ision is made .:
f or preventing rotation of the base member .
None o~ these disclosur~ shows ~h~ c:ombination oî d~vices simi~ar to tho~e disclosed her~
~ ~ ~ Suqgestion of blun points or dis~ectors for :~ 30 producing channel within the interla~ellar boundariesare ~ound. See, for instance, U.S. Pat. No. s,osd,sss~, to Simon and ~'Intrastromale Implanta~ion Eines ustierbaren Kunstofforings Z~ Iornhau Trefrak~ion Sanderung"~ Hartma~n et al., Kongress der Deutschen : 35 Gesellschaft f~r Intraskularlinsen Implantation, pp.

W093/2~763 . PCT/US93/~3~14 211775~ _4_ . .

465-475. They do not suggest the special relationship shown with the dissector support.
~ n optional aspect of this invention is the use of pin~ whi~h engage the front of the eye to prevent rotation of the inventive device during use.
U.S. Pat. No. 4,429,696, to Hanna, shows a surgical apparatus for pr~cisely cuttlng QUt the cornea of the eye by making at least one circular incision. The device is h~ld to ~he front of the eye by a series of claws, which optionally may be retractable, and suction placed on the central portion of the eye during the cutting operation. There is no suggestion of using the claws in cooperation with an annular vacu~m ring.
Finally, the invention may optionally include a soft base conformable to the surface of the eye.
Such devices are kn~wn. See, for example, published PCT Application W051/08711, to Kilmer et al., ~ : shows a device for re-profiling a cornea. The device :~ rests on a resilient vacuum ring which is adapted to sit ~ 20 on the sclera portion of an eye whic~ surrounds the :~ cornea which is to be re-profiled. The top side of the vacuum ring has a n~mber of positioning pins which allow it to be connected to the remainder of the profiling ~, ~
apparatus.
~:~ 25 The invention described herein i~ a device for ~: producing in the corneal stroma, th~ circular pathway : ~ ne~ded for the inse~tion of ~he ICR u~ing a suction ring which detachably adheres to the front of the eye.

~ 30 Brie~ Desc~iptiQ~ of_the D~aw n~s :1 ; Figur~ 1 is a horizontal section of an eye.
Figure 2 is a horizontal ~ection of the ankerior portion of an eye.

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WO 93/~0763 2 1 1 7 7 ~ 3 ~C~/US93/û3214 Figure 3 is a front perspective view of the con~;tituent parts of the invantive vacuum device and their relat:ionship to t~e eye during use.
Figure 4 is a bottom view of the base of the vacuum deviceO
Figure 5 is a bottom view of the c:enterirlg insert f or the inventive de~ric~ .
Figure 6 is a bottom view of the dissector ~nd its supporting insert barrel zs used in the inventive 1 Q deYice .
Figure 7 is a side view of the dissector blade.
Figur~ 7a is a sid~ cross-s~etion of the dissector blade.
Figur~s 7b and 7c are top and side views of the tip of the dissector blade~
Figure 8 is a side cross-section view of the vacuum devis::e in place on th~ eye durins~ the step of making the initial incision for later installation of an R.
Figur~ 9 iæ a side c:ross sectiorlal view of the ::
2 0 vacuum device in place during the step of dissecting : c:ircular ch~nnel in th~ corr~al stroma.
Figure lO is a bottom view of a variation of the inve~stion utilizing multiple vacuum chambers.
Figure 11 i~ a side cre~ss-~;ectional view of the 2 5 in~entive variakion shown in Figure 10 .
:~ Fi~r~ 12 is a bottom Yi~W o:f a variation of th~ inv2ntis~ uti lizing a singl~ cham~Qr in the base.
Fis~re 13 is a partial ~ide cro~s sectional vi~w o~ a var~atiorl of the inven~ion s~own in Figure 12.
: Fi~r~ 14 is a bottGm Yiew o~ a v~riation of the invention also utilizing multiple vacuu}ll chan~bèrs-Figure 15 is a partial sid~ c:ross-s~c~ional Yiew of ~he variation shown in Figure 1~.
Figure 16 shows a ~oft inserl~ suitable f or producing a ~cuum on th~ front of the eye.

W093/2~763 PCT/US93/03214 2117753 -6- , ``

Figures 17, lB and 19 are enlarged side cross-sectional views of peripheral or outer edge of the vacuum base wh~re they would m~t the surface of the eye during use.
Figure 20 shows a ~ottom view of a variation of the device which incorporates radial walls within ~he vacuum chamber to help preve~t rotation of the vacuum base during ophthalmic operations.
~igure~ 21, 22 and 23 show partial cross-sectional view~ of three variations of the radial wall : devices placed in ~he vacuum chamber ~hown in Figure 19.
Figure 24 is a bo~tom view of a vacuum de~ice showing, in particular, an insert utilizi~g a number of pins for engaginy the anterior surface of the eye during the eye ~urgery.
Figure 25 is a side view cross-section of the device of Figure 24.
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Figures 26, 27, 28, 29 and 30 depict the steps o~ using the inventive device to prepare the eye and 0: : ins~all the I~R in the corneal stroma.
Fi~ure 31 shows the positioning of the ICR in the stromaO

escri~ion o~_the_In e~ti~n : : 25 ~ ~ Prior to explaining ~h~ details of th~
; inventlve devices~l a short explanation of ~ e physi~logy of ~ ~the ~iy~ is needed t:o apprecia e ~he functional relationship of the device to thie ~iye.:
Figur~i 1 shows a horizontal ~ec:tion of the eye 30 ~wii~ch the globa~ ll of the eye r~embling a ~pheire wi~h an anterior ~ulged spherical po~tion repx~sentirlg the cornèa 12.
The globe 11 of the eye consist~i of three ~: ~
concentric coverings enclosing the various transparent media- through which the light must pa-~is beifore reaching , ~ .

W~93~20763 211~53 PCI~IJS931032~4 the sen~itive retina 18. The outermost covering is a f ibrous protective portion, the posterior f ive-sixths of which is white and opaque and called the sclera 13, and sometimes ref erred to as the white o~ the eye where 5 visible to the front. The anterior one-sixth of this outer layer is the tran parent cornea 12~
A middle covering is mainly vascular and nutritiYe in function and i~ comprised of the choroid ~ 4, ciliary body 16 and iris 17. The chors~id 14 generally 10 functions to maintain the retina 18. The ciliary body 16 is involved in suspending the lens 21 and accommodation of the lens. The iris 17 is the most anterior portion of the middle covering of the eye and is arranged in a frontal plane. It is a thin ::ircular disc corresponding 15 to the diaphragm of a camera, and is perforated near its ce3~tq~r by a circular aperture called the pupil 19. The ~ize of the pupil varies to regulate the amount of light which r~aches the retina 18. It contrac:ts alsc~ to accommodation, which serves ~o ~harpen th~ ~ocus by 2 0 diminishing ~pherical ab@rration . The iris 17 divid~s ~he spa ::e be ween the corrlea 12 and the lens 21 into an anterior chamber 22 and post~rior cha~ber 23. The . :
: :inne~ost portiorl of co~vering is the retina 18, con~i~ting of nerve eleDIents which ~orm the true 2$ rec~pti~e portion ~or visual impr~ssions.
~ e r~:ina 18 is a par~ of the ~rain ari~ing as an ou~growth from the fore-brain, with the optic nerve ~4 ~erving as a f iber trac:t ~onnecting the retina part of the brain ~ith th~ fore-brain,. A layer o~ rods and 3 0 cones, lying just beneath a pigmen~ed ~piphilium on ~he anterior wall o~ the r~tina serve as visual cells or photorec:eptors which ~ransform physical energy (~ight) into nerv~ iIapulses.
The ~itreous body 2 6 is a tralnæparen~
35 gelatinous mass which fills the postexior four-fifths of W093/2~763 PCT/US93/Q3214 j~?~, 21177S3 -~-the globe 11. At its sides it supports the ciliary body 16 and t~e re~ina 18. A frontal saucer-shaped depression houses the lens.
Th lens 21 of the ~ye is a transparent bi-convex body of crystalline appearance placed between the iris 17 and ~itreous body 26. Its axial diameter varies markedly with acco~modation. A ciliary zonule 27, consisting Qf transparent fibers passing between the ciliary body 16 and lens 21 serves to hold the lens 21 in position and enables the ciliary muscle to act on it.
Referring again to the cornea 12, this outermos~ fibrous transparent coating resembles a watch glass. Its curvature is somewhat greater than the rest of the globe and is ideally spherical in nature.
However, often it is more curved in one meridian than another giving rise to astigmatism. A central third of the cornea is called the optical zone with a slight flattening taking plac~ ou~wardly thereof as the cornea ~ : ; thickens t4wards its peripheryO Nost of the refraction : ~ 20 of th~ eye takes place through the cornea.
: Ref erriDg to Figure 2, a more detailed drawing o~ the anterior portion of the globe, shows the various layers of the cornea 12 comprising an epithelium 31.
Epithelial cells on the surface thereof function to 25;: maintain tran~parency sf the cornea 12. These epi~halial cell~ are rich in glycog~n, enz ~ e and acetylcholine and their activity regulat@s ~he c~rneal corpuscles and con~rols th~ transport of water ~nd electrolytes through the lamellae of the stroma 32 of the cornea 120 An anterior li~iting l~ina 33, re~erred to as owman's membr~ne or layer, is po~ition~d between the epiphilium 31 and the stroma 32 of the cornea. The :~ stroma 32 is comprised of lam lla having band of fibrils ~:~ parallel to each other and cros~ing ~he whole of the cornea. While most o the fibrou~ bands are parallel to .. , W093/20763 PC~/U~93/03214 `` ` 21177S3 _9_ th~ surface, some are oblique, especially anteriorly. A
posterior limiting lamina 34 is referred ~o a Descemet's membrane. It is a strong membrane sharp~y defined from the stroma 32 and rasistant to pathological processes of the cornea.
The endothelium 36 is the most postarior layer of the cornea and consists of a single layer of cells.
The limbus 37 is the transition zone between tAe conjuncti~a 38 ~nd ~clera 13 on the one hand and the : 10 cornea 12 on the other.
Figure 3 shows the various c~mponents used in this inventive surgical device. The support base ~50), includes an annular circumcorneal vacu~m ring (52~ at the end proximal the cornea and a cylindrical or central bore (54) extending from the end of the support base distal the eye (56). The s~pport base (503 typically contains a vi~wing port (55) through the extension wall o~ the base to allow the surgeon to make the initial incision into the ~ye and to clearly view the operational steps which ta~e place at the corneal surface. The vacuum is brought in ~rom vacuum source line (58). The circumcorneal Yacuum ring (52~ :is configured so that it m~ets wi h and seals the front of the eye rendering the support base (50) relatively immobile when the support base is applied 5 : ~o the front of the eye (56) and a sui~able vacu~m is applied to ~he~acuum source line (58~. The vasuum cha~ber ~or~s an ::annular vacuum ~pace against the front o~ the aye. The support basa (50) may also have a pin : ~ t60) which ~erves:as an antirotatcry devic~ for corneal centering guide ~62). ~lso sh~wn in Figure 3. is the inciso~ blad~ (68) which is inserted by ths surgeon through the viewing port (553. An incision blade (~8) is of a size and configuration which allows the knife to enter the cornea at a depth and angle suitable ~or later ~: 35 W093~20763 PCT/USg3/03214 ..
2117753 -lo-introduction of the dissector blade (66) into the intracorneal stroma.
Figure 4 shows a bottom view of support base ~03 in which the circumcorneal vacuum ring (5Z) may be clearly viewed. The circumcorneal vacuum ring (52) is made up of an inner wall (70) terminating on its inside by the central bore (54). The central bore ~54) is at least large enough to see the entirety of the dissector blade (66) as is discussad ~elow. The central bore (54) has an axis which ~ubstantially coincides with the axis .of the dissector blade. The central bore (54) is desir-ably of a length such that the ratio of the bore's length to its diameter is b tween 0.25:1 and 15:1; specifically ~etween 0.4:1 and 1:1; at least about 1:1 and less than about 3:1; or at least about 3:1 up to about 15:1~
Pr~ferably, the ratio is about 2.5:1. This sizing allows easy manipulation by the surgeon. The outer vacuum ring wall (72~ desirably forms the outside of the support base (50). Interior to th~ circumcorneal ~acuum ring (52) may 2Q be one or more ridges (74) which extend down to the corn~al surface when the support base is attached to.the guide~. ~The ridges are position~d wi~hin the circum-: corneal vacuum ring (52) to prevent rotation of thasuppor~ base (50~ during any ~urgical opera~ion.
25~ ~ariations o~ th~ ridge design will be discussed below with re~ard to Figur~s 20 through ~3. Th~ opening (76) o the ~aeuum source line ~5~) ic shown in Fi~ure ~.
Figure S sho~s a bottom view of corneal : aentering ~nd fixation guide (62 ~ . Thi~ guide ( 62 ) f its down within the inner barr~l ~54) of support base (50~
and a gro~Ye (78) within ~he outer surfaca of the ~uide slides oYer and engages pin ~60). In this way, corneal centering and fixation guide (~2) doe~ not rotate with resp~ct to support base (S0). The in~ide bore (80) and the reticle are used to allsw centering o~ the support WO 9~/~0763 PCr/USg3/03214 2 ~ 1 7 7 5 3 ~

~a~e ( 50 ) about the cornea and to allow making a marking cut with incision marker ( 63 ) . Once the surg~on ~l~termines that the support base ( 50 ~ is properly centered by using the corneal c~ntering and f ixation S guide ( 62 ), vacuum is appli~d through vacuum source line t~8) and its terminal opening ~76) in the circumcorneal vacuum ring ( S2 ~ .
Once support ba~e (50) is a~fixed to tha front of ~he eye, the corneal centering and f ixation gl~ide ( 62 ,) 10 is removed ~rom the center bore (54) of th~ support base ~50) and the incision for insertion of the dissectc~r blade (66) is made. After the initial incision is : ~ completed, the dissector barrel (64) is inserted down into the inner bore (54) of the support base (50). The 15 diss~ctor ~lade ( 66) is attached to the dissector bzlrrel ( 64 3 by dissector blade support arm ( 84 ) . As the barrel ~; rotates, it def ines a barrel axis . The barrel axis is :: ` coincident to the blade axis discussed below.
FIqure 7 shows the desired features o~ the 20~ dissec:q~or blade (66) in greater detail. The blade, in crosssection, i~; desirably rectangular in cross-section.
miS permits a~ large amount of material to be inc:orporated in the bla~le and yet ~o:rm a silbstantially ~ :: : r~ctangular pa~h in ~he interlamellar spaces of the :; :25 corneal stromaO The blade (66) a~; waL~; ~;hown above, is in th~ shape of a DIajor arc of up ~o 3500 ha~ing as its :: cen~er the axis~ ~65) a shown in Figure 7. The blade's ~a~or arc is in a planQ perpendicular to ~ha~ axis (65).
blade may be taper~d on its s~aller edge as is shown : ~ 30 in Figure 7a and indeed may be o~E any convenient shape althoughi we ~have ~ound the tws~ not~d cross~ectional ~hapes (i.~., rectangular or h~xagonal in whic:h two opposite sid~s are longer than t:he r@~ainins~ *our) to be pre~erred. Figure 7a shows the cone angle (67~ of t~e 3 5 dis~ector blade as is discussad below and the diameter W0~3/20763 PCT/US93~03214 211~3 -12- ``

(69~ of the dissector b~ade (66~. This diam~ter is preferably viewable through the upper end of the dissector barrel (64).
The blade is formed so that the dissector blade support axm (84) is at an angle ~ of up to about so~.
The angle of the blade support a ~ (84) ~o the plane of the blade 566) may be a value of 0 to 90. It is preferably between 0 and 80, more preferably the angle is 10-~0 and most prefarably about 3~ ~+ 5o) to th~
plan~ of dissector blade ~66). This angle r~sults in the diss~ctor blade support arm (84) being generally perpen-dicular to the cornea when it is inser~ed into the incision provided ~or introduction of the dissector blade (66~ in~o the corneal stroma. This angle~ although not absolute~y critical, is desirable and has been found to prevent tearing of the ~piphilium during the cornea~
: o?eration~ The length of blade angle support arm (84) i5 ~ufficient that the entire diss~ctor blade is visibl through the top o~ the dissector barrel during use--see Fi~ur~ 6. ~s was noted with regard to Figure 3, the outer di~meter o~ the dissec~or barrel (64) is the ~amç
as the bore (54) of the b~se (50). The ovsr~ll re~ation-ship ~f the sizes of the diameter of the arc ~69) of the bl~de to the l~ngth of ~he dissector barrel is desirably 25 : chosen so that:the ratio of ~hat leng~h to the 2rc dia~ter i~ be~een;0.25:1 and 15~ pec'fieally between 0.4:1:a~d 1:1, at~least about 1:1 and le~s than about 3:1; and a~ lea~t about 3:1 but le~s than 15:1. ~gain these ratios all~w:~ase of manipul~tion ~y th~ surgeon~
3Q The di~ector blade (66) has ~wo other physical parameters which we belie~e to be i~ortant to ~hel ' ~: effective operation of the support base ~503 in providing ~, : an interla~ellar channel in the corneal stroma. Upon ~ , r~tation of the discectsr barrel (64), ~he dis ector blade (66) must move in a pa~h which is substantially W093/2076~ PfCT/U~f93~03214 {~`~ 21~ 77S3 -13- f planar. That is to say the path of the di~sector blade (66) as it moves in the corneal intrastromal lamellar space described above, must not v~ry either up or down during the dissector barrel (64) rotation. The distance "a" shown in Figure 7 is a constant. Tha blade can be considered to be in a plane which is perpendifrular to the axis (6~) which forms the center of ring (66).
Similarly, the cone angle ~ (67) is prefer~bly 112 (+30). Again, this permits the dlssector blade (66) to produce a channel which is parallel to the lamella found in the corneal stroma. The cone angle m~y, of course, vary a few degrees dependent on such variables as the geometry of the ICR installed, the size ~ D~ he eye, and the amount of correction r~quired.
:~: 15 Figures 7b and 7c show o~e desired tip :~ configuration of the dissector blade (66). We have found that a comparatiYely blun~ but rounded device ~ill provide an intrastro~al channel fairly pr~isely in a constant depth within the lamella. Sharper blades have a ; 20 t~ndency:to cut through the l~mella and produce a less desirable intrastro~al channel.
Figure 8 shows in a cross-section the s~ep of creating the~incision in the front of the 2ye uf~ing knife 68). The:support base (50) ff-eCUred by Cirf umcorneal 5~ vacu ~ ring (52)~is in plac~ as is ~he corneal centering and~ixation quide (6~3. T~e knife (68) haa been brought ;;dow~ through;the orneal centering and fixation guide (62)~into the~epi~helium and the str~a of the eye (56).
once h~steps of cent~ring and initial 30:: inc~ion are co~plete, h~ corneal centering and fixation guide (62) and knife (68) are re~ov~d and the st~p ~hown in Figure 9 i~ carried out.
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In Figure 9, ag~in th~ support bas~ (50) is in : place on ~he fron~ of the eye (56) secured by t~ vacuum in circumcorneal vacuum ring (52~. The dissector barral ' ~'VO 93/20763 PCI~US93/03~14 21177~3 -14-( 64 ) having dissector blade ( 66) on its lower end is introduced into the inner bore of the support base ( so ) .
The leading edge of the dissector blade is introduced into the incision made during the step shown in Figure 8 5 and the dissector barrel is rotated as hown. The dissector barrel is rotated far enough to make a-f~ll circular channel or until the dissector blade support arm ( 84 ) reaches the insertion made into the eye . Further rotation would cause tearing of the eye.
lû The dissector blade is th~n rol:ated in an opposite direction so to remove the dissector blad4 ( 66) from the channel it has just producedO We have also found it desirable to complete the interlamellar channel by using another dissector barrel which rotates in the lS opposi~e direction.
The ICR may be introduced as d~scribed below.
The circumcorneal vacuum ring may be produced in a variQty of desired a~rangements. For instance, in Figures lO and ll, a ~nulti-cha~bered device i~; shown. In 20 Figur~ lO, a bottom view of the suppor~ base (86) i~
ound. The circumcorneal vacuum ring is ~ade up o~ three ~: distinct cham~ers (88), each of which are connected to the vacuum~ source lin~ opaning (90). This variation is desired when ~dditional ~;upport i5 needed betw~en the 2s outer support base wall (92) and ~he suppor~ base inner bore ~ 94 ) . Bec:~use thç~ f orce applied to the ey~ is prsportional to the area subjeeted to vacuum on the front of the eye, this variation c:an be used to additional area under ~racuum to ~e d~vice without trauma to the eye, As 30 may be ~;~en in Figure ll, the various in~:arior walls (96) are of a different height allowing them to ¢onfor~nl to the f ront of the eye .
Figures 12 and 13 show, re~pec:tively, a bottom view ~nd a 8ide partial cross-~ectional ~riew o~ another 35 variation of t:he support base (98) in which the W093/~0763 P~TJ~S93/03214 2 1 17 7 5 3 --1S--- !

circu~corneal vacuum ring does no~ completely encircle the cornea. This configuration allows the ~iewing port (as shown in Figure 3 as (55)) to be quite large and allows the surgeon views of the cornea both fr~m above through the inner bore of the dissector barrel or through the side viewing port during the production o~ the inner stromal channel. Spe ifically, tha open part of the channel meets the ~ye at surface (100) and the vacuum source line opening provides a vacuum source to th~
opening which fits against the eye. Support base ~102), as is shown in Figures 14 and 15, is a multi-chamb~r dq~ice analogous to that found in Figures 12 and 13. The device and add~d upper chamber (104) al~ow the vacuum to more easily circumnavi~ate the cornea.
~; 15 Figure 16 shows a side perspective cross-~: section of ~n ins~rt (101) which is suitable for inclusicn in the lower end of the support base. This insert has a support ring ~105) which may be metal, stiff plastic or other suitable material~ A rubber s~al (103) which fits again~t the edge is bonded to the support ring (105~. The support ring may have holes (107) inserted therein so to allow vacuum access when the insert is placed in~o a suppor~ such a~ that shown in Figures : 2:0-23.
: ~ Figures: 17, 18 and ~g show thre~ variations of the 8ur~ace8 which are desirably use~ as the surfaces which m~et ~ e~:cornea in ~he circumcorneal vacuum ring.
:Specifically~, ~igure~ 17-19 ar~ partial cross-sec~ions of the va~u~m chambers showing various edge~ of the : 30 circumcorneal~acuum chamber where ~he edges ~eet the ~,; , I , ; I
': ' surface o~ the eye. Sp~cifically, Figur~ 17 shows a varia~ion in :which the circu~ncorneal cha~r (104) has an outer sur~ace tl06) which is dispo~d at an angle J such that J whiah ~s~ the angle which a tangent to a patient's cornea would make a~ tha~ point. Similarly, inner ' ~:

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WO 93/20763 PCI/US~3/03214 2 il77S 3 -16- ~

chamber ~dge ~108 ) is cut at an angle K such that the inner chamber edge (108) would lie substantially flat against the pati~nt's cornea. In Fi~ure $9, the v~cuum ch~mber (104) has an outer rounded chamber edge (110) and S an inner cha~ber edge ( 108 ) which is similar in design to the variation shown in Figure 17. The Figure 18 -variation uses an outer cham~er edge ~112 ~ which is som~what sharper but is not so sharp as to cause subs~antial trauma or c~tting of the corneal surf ace .
10 The iI-ner cha~ber edg~ ~114 ) is of a similar chape .
The vacllum chamber walls, the circumcorneal rings, and the cupport base may be made of a variety of materials including various plastics, metals, and pliable materials such as~ natural and synthetic rubbers.
The pref erred variant of the c:ircumcorneal vacuu~ ring contains a m3mber o~ ridg~s or vanes which serve to h~lp prevent rotation of the support base during the ophthalmic op~ration. There are a number of ~uitable -~: ~ays of introducing such anti-rotating features. ~or 20 in~tance, in Figur~ 3, shc~rt ridg~s (~6) are included ~oth in the in~aer and outer walls oX ~he circumcorneal vacuum ring ( 52 ), The lower terminus of th~se short ~: : vanes (46) rest against the cornea and a~ter vaculam is applied to ~ vacuum ring (52), th~ corn~a is drawn up 2~ to ~he spac~ ~urrounding the vanes ~46) and the vanes preYent th~ upport base ~rom rotating . Figures 2 0-2 3 h~w other versions of vanes suitable for pr~enting rotatic3n of the 8upport bas~ (S0). Figure 20 ~hsws a botto~ view vf support base ~50) in which eleven vane~
30- (116J are interposed within the circumcorn~al ~racuum ring (52). As i~s shown in partial cro~-section o~ the rendition shown :in Figure 20, the vanes have s~veral :~ identifying features. Th~ surf2lce (118) must meet ~he surîace of the cornea after the suction is applied to the 3 S ring . There are pathways ~variously through the opening W093/20763 2117 7 5 3 PC~/US93/Q3214 ol7-- .

~120) and the stu~ wall (122) which allow the vacuum to be distributed from the vacuum line opening (124) to be distributed evenly about the full circumference 9f the circumcorneal vacuum chamber. The pathways for the distribution of the vacuum around the chamber is not ~ritical. Multiple vacuum inlets are suitable and other channel shapes are appropriate. Figure 22 shows still anoth~r variation of the vacuum chamber vane (126) also utilizing a stub wall (122) to al~ow ~acuum distribution.
The vacuum cha~ber vane (126) US2S an additional slot (128) to distribute the vacuum. Once again, however, the lower surface of the v~ne meets f}ush with the eye and :~ forms small indentations within th~ cornea once vacuum is applied.
lS Fi~ure 23 shows a variation in concept for vane :: shape. The variation~ inst~ad of pro~iding for ~lat ~; surface against ths corn~a instead is steppsd in such a way th~t small points (130) which are cut into th~ vane (126) engage ~h:e~cornea when vacuu~ is applied to the d~vice. Vacuum is distributed through hole (120) and in ~: the sparee ~o ~ ed between outer wall (132) and the lower vane point, the sp~ce between the two vane points ~130~
and the space~between the upp~r vane point (130) and the inner wall (134).:~
25~ Figures 24 and 25 sh~w another variation in which an ins~rt (136) containing a n ~ sr of pinæ (138) ~ay be included as an integral portion of th~ suppoxt : ba~s (50). Fiyure 24 sho~s a bottom view of the ring as it i~ placed within the ~tt~ portion of the support : 30 base (50). The insert ring (136) contain~ a ~ur~ace (140) which se~ves as the inner wall o~ the circumcorneal acuum chamber (142~. In thi~ variation of the invention, pins (138~ extend for a short distance through ; that 510ping wall (140) ~o that as vacuum i~ introduced into chamber (142), the pins engage the eye and penetrate W093/20763 PCT~U~3/03214 ~ 1 17 ~ 5 3 18--a short distance into the cornea. The insert ring may also includ~ slots (142) to allow the vacuum to be di~tributed geometrically about the pins with a bit more regularity. The insert ring ~136) ~ay be placed in a chamfer within the interior surface o~ support basP (50~
as is shown in a cross-section in Figure 25. As-is shown in Figure 25, the surface of the insert ring which meet~
th~ anterior cornea (l40) is, or may be, sloped in the same fashion as is the anterior wall (108~ found in Figures 17 and 18. Incidentally, the outer vacuum chamber wall ~144) is shown in cross-section in Figure 2S
to have a square shoulder. It has been observed that ~:~ this configuration causes only minimal trauma when u~ed in this inventive device with an appropriate amount of vacuumO m e trauma is seen to be even less than that : obser~ed with vacuum chamber outer walls ~106) such as is shown in Figure 17.
: Th~se combi~ations of vacuum chambers, vanes : and ridges within the vacuum ch~mber, insert rings with ~2~0 and without pins~,~all serve to pr~vent t~e rotation of the:devic~ during the ophthalmic op~ration for which this device i5 ibtended. Furthermore, the use of the insert ring:~:helps to prevent twisting of the corneal sur~ace during insertion o~ the dissector blada, as e~plained 25~ b~low. ~ : ~

:: :
: ~ on o~:the I m entive De~i¢e Fig~res 26-29 show the pro~ess for using the c~m~ination~de~ic~.
Figur~ 2S:shows a co~ ination o support base (50) and corneal centering and fixation yuide (62)i placed on the front of ~a patient's eye (146)~. ~h~ surgeon centers the device on the ~ye using reticl~ ( 82 ) . At ; ~ this point, vacuum has not bsen applied to the circumcor~al vacuum ring (52). }~ow~ver, as soon as the , device is considered to be center~d, vacuum is applied as is sh~wn in Figure 27 through vacuum source line (S8).
The amount of vacuum applied is known. The corneal cantering and fixation guide (62) is then removed from support base (50). It may be observed that wi-hin rircumcornsal vacuum ring (52) is a slight bulging of the eye. This bulging of the eye contacts the vanas within the vacuum chamber; such vanes are disc~lssed with relat~on to Figures 3, 4, 20, 21, 22 and 23, and the insert ring shown in Figures 24 and 25. This contact with the van~s helps prevent rotation or other movement of the support ~ase (50). once the support base is firmly affixed to the eye, the lance (68) is brought ~hrough the window in the support base to produce a small incision ~148j~ in the cornea. The incision exte~ds through epithalium and Bowman's ~embrane and is approximately 1-2 ~ long and about 0.2 mm deep. The ~:~ incision is on a r~dius of the cornea. A small spatula which fits into incision (148) may b~ used to make an initial s~paration in the inner la~ellar layers at the bottom of incision ~148) within the stroma. This "teasing" of the lamella will facilitate the insertion of th~dissector blade (66). It should be noted at this : ~oint that the large viewing port (54) promotes ease of viewing for the surgeon onto th~ cornea parti~uIarly when us~d in conjunction with the large ID bore of the suppor~
@ (50)-Finally, dissector bar~el (S4) is introducedin o ~he support bas~ (50). The diss~c~or blade (66) is in~roduced in~o ~he cornea ~ ou~h in~ision (148) and ` I turned until dics~ctor blade support arm (84) n~ars the incision (14~). When the upport arm r~ach~s ~he incision, the rotation of dis~ctor barrel ~64~ and ~: attached d~ssector blad~ (~6) J it i~ reversed and the dissector blade is backed out of th~ inner subsurface W093/20763 2~ PCT/US93/03 14 la~ellar tunnel it has formed. The vacuum is then eased and support bas~ (50) is removed from the eye. Once the inventive device is removed from the eye, the ICR (150 may be introduced into the intrastromal channel just produced desirably wi~h a coating of hyaluronic acid or : other suitable material a~ a lubricant. The ends of ICR
(150~ may bs ~oined using techniques discussed in the patents discussed above.
This invention has been described and :10 exemplifi@d in some detail. Those having ordinary skill in this art would recognize variations and equivalents which would be well within the scope of the invention : disclosPd here but perhaps outside the scope of the appended claims~ It is applicants' in~ention that these equivalent ~aria~îons be included within the scope of this invention.

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Claims (28)

WE CLAIM AS OUR INVENTION:

1. A dissector blade assembly suitable for forming a generally circumcorneal interlamellar channel in an eye comprising:
a blade having a cross-section, which blade is in the form of a major arc having a diameter in a plane about an axis, said axis being perpendicular to the plane of the major arc of the blade, having a blunt end and a blade support end, and a blade support attached to the blade support end in which the blade support is at an angle of up to about 80° to the plane of the blade.

2. The blade assembly of claim 1 additionally comprising a generally cylindrical dissector barrel having an axis substantially coincident to the blade axis, said barrel connected to the blade support and having an inside diameter and an outside diameter.

3. A dissector blade assembly suitable for forming a generally circumcorneal interlamellar channel in an eye comprising:
a blade having a cross-section, which blade is in the form of a major arc in a plane about an axis, said axis being perpendicular to the plane of the major arc of the blade, having a blunt end and a support end, a blade support attached at one end to the blade support end of the blade and at the other end to a dissector barrel having an axis substantially coincident to the blade axis, and a generally cylindrical dissector barrel having a blade support end, a viewing end, an inside diameter, an outside diameter, and an axis substantially coincident to the blade axis.

4. The blade assembly of claim 3 in which the blade support is at an angle of up to about 80° to the plane of the blade.

5. The blade assembly of claims 1 and 4 in which the blade support is at an angle between 10° and 50°.

6. The blade assembly of claim 5 in which the blade support is at an angle of about 34° (? 5).

7. The blade assembly of claims 1 and 3 in which the blade cross-section is hexagonal, said hexagonal blade cross-section having two opposing sides which are longer than the four remaining sides.

8. The blade assembly of claim 7 in which the cross-section is positioned such that it forms a cone angle of 112° (? 30°).

9. The blade assembly of claims 2 and 3 in which the diameter of the arc of the blade is less than the inside diameter of the dissector barrel.

10. The blade assembly of claim 9 in which substantially all of the blade may be seen in the viewing end of the dissector barrel.

11. The blade assembly of claims 2 and 3 in which the ratio of the length of the dissector barrel along its axis to the diameter of the arc of the blade is between about 0.25:1 and 15:1.

12. The blade assembly of claim 11 in which the ratio is between 0.4:1 and 1:1.

13. The blade assembly of claim 11 in which the ratio is at least about 1:1 and less than about 3:1.

14. The blade assembly of claim 11 in which the ratio is at least about 3:1 but less than about 15:1.

15. The blade assembly of claims 1 and 3 in which the blade cross-section is rectangular.

16. The blade assembly of claims 1 and 3 in which the blade dissecting end is rounded.

17. A corneal vacuum centering guide and dissector assembly comprising a support base having a proximal end; a distal end; a central section having a wall with a generally cylindrical bore with a central axis which central section extends between the proximal and distal ends of the support bases the cylindrical bore having a length and a diameter and where the ratio of the length to the diameter is between about 0.25:1 and 15:1, and an annular vacuum chamber located at the proximal end and adapted to create an annular vacuum space when placed against the eye.

18. The assembly of claim 17 in which the annular vacuum chamber has an inner wall and an outer wall and at least one of the inner and outer walls have integral ridges or vanes which are adapted to extend down to and contact the eye during use.

19. The assembly of claim 18 in which the vacuum chamber contains integral ridges.

20. The assembly of claim 18 in which the vacuum chamber contains radial vanes.

21. The assembly of claim 17 in which the ratio is between 0.4:1 and 1.1.

22. The assembly of claim 17 in which the ratio is at least 1:1 and less than about 3:1.

23. The assembly of claim 17 in which the ratio is at least 3:1 but less than about 15:1.

24. The assembly of claim 17 in which the vacuum chamber contains an insert detachably mounted to the proximal end of the support base which insert contains short pins mounted to engage the cornea during use.

25. The assembly of claim 17 additionally comprising a corneal centering and fixation guide having an outer diameter which slidably fits within the cylindrical bore of the support and a reticle coincident with the central axis of the support base.

26. The assembly of claim 17 additionally comprising a knife adapted to place a small incision in the eye.

27. The assembly of claim 25 additionally comprising a viewing port through the central section wall.

28. The assembly of claim 17 additionally comprising the dissector blade assembly of claim 7.