surgical techniques for small incision cataract surgery 2

2.1Introduction

Phacoemulsification (phaco) means disassem-bly and removal of the crystalline lens. From itsintroduction in the late 1960s to the present,phaco has evolved into a highly effectivemethod of cataract extraction. Incremental ad-vances in surgical technique and the simultane-ous redesign and modification of technologyhave permitted increasing safety and efficiency.

Among the advances that have shaped mod-ern phaco are incision construction, continuouscurvilinear capsulorhexis, cortical cleavinghydrodissection, hydrodelineation, and nucle-ofractis techniques. The refinement of cataractremoval through a small incision has improvedphaco and permitted rapid visual rehabilitationand excellent ocular structural stability. Per-haps the most outstanding characteristic of thisera of phaco is the unrelenting quest for excel-lence that continues to challenge the innovativespirit of cataract surgeons.

2.2Wound Construction and Architecture

The availability of foldable intraocular lenseswhich can be inserted through small unsuturedphacoemulsification incisions [13] has created atrend away from scleral tunnel incisions to clearcorneal incisions [41].Among the disadvantagesof scleral tunnels are the need to perform con-junctival incisions and scleral dissections, andthe need for cautery to prevent operating in thepresence of blood. In addition, there is in-creased difficulty with oarlocking of the phaco

Surgical Techniques for Small Incision Cataract Surgery

I. Howard Fine, Mark Packer, Richard S. Hoffman

2

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∑ An incremental yet inexorable reduction in incision size and related morbidity has marked the recent history of cataractsurgery

∑ Continuous curvilinear capsulorhexis has improved stability and centration of intraocular lenses, helped to reduce poste-rior capsular opacification and spurred thedevelopment of endolenticular nucleo-fractics techniques

∑ Cortical cleaving hydrodissection has reduced the need for irrigation and aspiration of cortical material and the rate of posterior capsular opacification

∑ Chop techniques substitute mechanicalforces for ultrasound energy to disassemblethe nucleus, utilize high vacuum as an extractive technique to remove nuclear material and facilitate the achievement of minimally invasive surgery and rapid visual rehabilitation

∑ The promise of bimanual, ultra-small incision cataract surgery and companionIOL technology is today becoming a reality,through both laser and new ultrasoundpower modulations

Core Messages

tip and distortion of the cornea because of thelength of scleral tunnels.

Kratz is generally credited as the first sur-geon to move from the limbus posteriorly to thesclera in order to increase appositional surfaces,thus enhancing wound healing and reducingsurgically induced astigmatism [8, 43]. Girardand Hoffman were the first to name the posteri-or incision a “scleral tunnel incision” and were,along with Kratz, the first to make a point of en-tering the anterior chamber through the cornea,creating a corneal shelf [32]. This corneal shelfwas designed to prevent iris prolapse. In 1989,McFarland used this incision architecture andrecognized that these incisions allowed for thephacoemulsification and implantation of lenseswithout the need for suturing [44]. Maloney,who was a fellow of Kratz’, advocated a cornealshelf to his incisions which he described asstrong and waterproof [42]. Ernest recognizedthat McFarland’s long scleral tunnel incisionterminated in a decidedly corneal entrance. Hehypothesized that the posterior “corneal lip” ofthe incision acted as a one-way valve thus ex-plaining the mechanism for self sealability (aspostulated by Ernest in a presentation to the De-partment of Ophthalmology, Wayne State Uni-versity School of Medicine, Detroit, MI, on Feb-ruary 28, 1990). In April of 1992, Fine presentedhis self-sealing temporal clear corneal incisionat the annual meeting of the American Societyof Cataract and Refractive Surgery [5].

There have been surgeons who have favouredcorneal incisions for cataract surgery prior totheir recent popularization. In 1968, CharlesKelman stated that the best approach for per-forming cataract surgery was with phaco-emulsification through a clear corneal incisionutilizing a triangular-tear capsulotomy and agrooving and cracking technique in the posteri-or chamber [37]. Harms and Mackenson in Ger-many published an intracapsular technique us-ing a corneal incision in 1967 [33]. Troutmanwas an early advocate of controlling surgicallyinduced astigmatism at the time of cataract sur-gery by means of the corneal incision approach[12]. Arnott in England utilized clear cornealincisions and a diamond keratome for pha-coemulsification although he had to enlarge theincision for introducing an IOL [4]. Galand in

Belgium utilized clear corneal incisions for ex-tracapsular cataract extraction in his envelopetechnique [24] and Stegman of South Africa hasa long history of having utilized the cornea asthe site for incisions for extracapsular cataractextraction (R. Stegmann, personal communica-tion, December 3, 1992). Finally, perhaps theleading proponent of clear corneal incisions formodern era phacoemulsification was KimiyaShimizu of Japan [53].

In 1992, Fine began routinely utilizing clearcorneal cataract incisions with closure by a tan-gential suture modelled after Shepherd’s tech-nique [51]. Within a very short period, the su-ture was abandoned in favour of self-sealingcorneal incisions [17]. Through the demonstrat-ed safety and increased utilization of these inci-sions by pioneers in the United States, includingWilliamson, Shepherd, Martin, and Grabow[61], these incisions became increasingly popu-lar and utilized on an international basis.

Rosen demonstrated by topographical analy-sis that clear corneal incisions of 3 mm or less inwidth do not induce astigmatism [49]. Thisfinding led to increasing interest because of bet-ter predictability of T-cuts, arcuate cuts, andlimbal relaxing incisions for managing pre-ex-isting astigmatism at the time of cataract sur-gery. Surgeons recognized many other advan-tages of the temporal clear corneal incision,including better preservation of pre-existing fil-tering blebs [47] and options for future filteringsurgery, increased stability of refractive resultsbecause of decreased effects from lid blink andgravity, ease of approach, elimination of the bri-dle suture and iatrogenic ptosis, and improveddrainage from the surgical field via the lateralcanthal angle.

Single plane incisions, as first described byFine [15], utilized a 3.0-mm diamond knife.After pressurizing the eye with viscoelasticthrough a paracentesis, the surgeon placed theblade on the eye so that it completely applanat-ed the eye with the point of the blade positionedat the leading edge of the anterior vascular ar-cade. The knife was advanced in the plane of thecornea until the shoulders, 2 mm posterior tothe point of the knife, touched the external edgeof the incision. Then the point of the blade wasdirected posteriorly to initiate the cut through

20 Chapter 2 Surgical Techniques for Small Incision Cataract Surgery

Descemet’s membrane in a manoeuvre knownas the dimple-down technique. After the tip en-tered the anterior chamber, the initial plane ofthe incision was re-established to cut throughDescemet’s in a straight-line configuration.

Williamson was the first to utilize a shallow300–400mm grooved clear corneal incision [21].He believed that the thicker external edge to theroof of the tunnel reduced the likelihood oftearing. Langerman later described the singlehinge incision, in which the initial groove meas-ured 90% of the depth of the cornea anterior tothe edge of the conjunctiva [40]. Initially he uti-lized a depth of 600mm and subsequently madethe tunnel itself superficially in that groove, be-lieving that this led to enhanced resistance ofthe incision to external deformation.

Surgeons employed adjunctive techniques tocombine incisional keratorefractive surgerywith clear corneal cataract incisions. Fine usedthe temporal location for the cataract incisionand added one or two T-cuts made by the Feast-er Knife with a 7-mm ocular zone for the man-agement of pre-existing astigmatism. Others,including Lindstrom and Rosen, rotated the lo-cation of the incision to the steep axis. Kershnerused the temporal incision by starting with anearly full thickness T-cut through which hethen made his corneal tunnel incision. For largeamounts of astigmatism he used a paired T-cutin the opposite side of the same meridian [38].Finally, the popularization of limbal relaxing in-cisions by Gills [25] and Nichamin [46], addedan additional means of reducing pre existingastigmatism.

The 3-D Blade (Rhein Medical, Tampa, FL)improved incision construction with differen-tially sloped bevels on its anterior and posteriorsurfaces. This design allowed the surgeon totouch the eye at the site of the external incisionlocation and advance the blade in the plane ofthe cornea without dimpling down. The differ-ential slopes allowed the forces of tissue resist-ance to create an incision characterized by alinear external incision, a 2-mm tunnel, and alinear internal incision [18]. The trapezoidal 3-DBlade also allowed enlargement of the incisionup to 3.5 mm for IOL insertion without alteringincision architecture.

Following phacoemulsification, lens implan-tation, and removal of residual viscoelastic,stromal hydration of the clear corneal incisioncan be performed in order to help seal the inci-sion [16]. Stromal hydration is performed bygently irrigating balanced salt solution into thestroma at both edges of the incision with a 26- or 27-gauge cannula. Once apposition takesplace, the hydrostatic forces of the endothelialpump help seal the incision. In those rare in-stances of questionable wound integrity, a sin-gle 10–0 nylon or Vicryl suture is placed to en-sure a tight seal.

Clear corneal incisions, by nature of their ar-chitecture and location, have some unique com-plications associated with them. If one inciden-tally incises the conjunctiva at the time of theclear corneal incision, ballooning of the con-junctiva can develop which may compromisevisualization of anterior structures. In this case,a suction catheter may be used to aid exposure.Early entry into the anterior chamber may re-sult in an incision of insufficient length to beself-sealing. In addition, incisions that are tooshort or improperly constructed can result in anincreased tendency for iris prolapse. A singlesuture may be required in order to assure a se-cure wound at the conclusion of the procedure.On the other hand, a late entry may result in acorneal tunnel so long that the phaco tip createsstriae in the cornea and compromises the viewof the anterior chamber.

Manipulation of the phacoemulsificationhandpiece intraoperatively may result in tearingof the roof of the tunnel, especially at the edges,resulting in compromise of the incision’s self-sealability. Tearing of the internal lip can alsooccur, resulting in compromised self-sealabilityor, rarely, small detachments or scrolling of De-scemet’s membrane in the anterior edge of theincision.

Of greater concern has been the potential forincisional burns [19].When incisional burns de-velop in clear corneal incisions there may be aloss of self-sealability. Closure of the woundmay induce excessive amounts of astigmatism.In addition, manipulation of the incision can re-sult in an epithelial abrasion, which can com-promise self-sealability because of the lack of afluid barrier by an intact epithelium.Without an

2.2 Wound Construction and Architecture 21

intact epithelial layer, the corneal endotheliumdoes not have the ability to help appose the roofand floor of the incision through hydrostaticforces.

In a large survey performed for the Ameri-can Society of Cataract and Refractive Surgeryby Masket [56] there was a slightly increasedincidence of endophthalmitis in clear cornealcataract surgery compared to scleral tunnel surgery. However, the survey failed to note theincision sizes in those cases where endoph-thalmitis in clear corneal incisions had oc-curred. Masket described several generally ac-cepted techniques of prophylaxis, includingpreoperative topical antibiotics, 5% povidone-iodine prep and draped eyelashes

Colleaux and Hamilton [7] found no signifi-cant difference in the rate of endophthalmitiswith respect to clear corneal versus scleral tun-nel incisions in a retrospective review of 13,886consecutive cataract operations. They reporteda significant prophylactic effect of subconjunc-tival antibiotic injection, but found no benefit topreoperative antibiotic drops. In an evidence-based update, Ciulla, Starr and Masket foundthat current literature most strongly supportsthe use of preoperative povidone-iodine anti-sepsis [6]. They found little change in the risk ofendophthalmitis in the United States over time,from 0.12% in 1984 to 0.13% in 1994.

Clear corneal cataract incisions are becom-ing a more popular option for cataract extrac-tion and intraocular lens implantation through-out the world. With clear corneal incisions wehave achieved minimally invasive surgery withimmediate visual rehabilitation. Clear cornealincisions have had a proven record of safetywith relative astigmatic neutrality. In addition,clear corneal incisions result in an excellent cos-metic outcome. We expect that they will contin-ue to increase in popularity, especially as newermodalities, such as non-thermal bimanual pha-co, become the standard of care.

Summary for the Clinician

∑ Increased operating efficiency, improvedcontrol of astigmatism and foldable intraocular lens technology have led to increasing utilization of self-sealing, clearcorneal incisions for cataract surgery

∑ Pre-existing corneal astigmatism may be effectively treated at the time of cataractsurgery by means of incisional keratore-fractive techniques

∑ Successful clear corneal incisions requireattention to detail in order to avoid uniquecomplications associated with them

2.3Continuous Curvilinear Capsulorhexis

Implantation of the IOL in an intact capsularbag facilitates the permanent rehabilitative ben-efit of cataract surgery. For many years, sur-geons considered a “can-opener” capsulotomysatisfactory for both planned extracapsularcataract extraction and phaco. Problems relatedto malposition and decentration of implantedposterior chamber IOLs were later recognized.In 1991, Wasserman and associates [59] per-formed a postmortem study that showed thatthe extension of one or more V-shaped tears to-wards the equator of the capsule produced in-stability of the IOL and resulted in IOL malposi-tion.

We are fortunate to have benefited from thework of Calvin Fercho, who developed continu-ous tear capsulotomy (as presented in “Contin-uous circular tear anterior capsulotomy,” WelshCataract Congress, on 9th September, 1986) andGimbel and Neuhann, who popularized contin-uous curvilinear capsulorhexis (CCC) [28, 29,45].

The technique of CCC is not difficult to learnif certain basic principles are observed:1. The continuous capsular tear should be per-

formed in a deep, stable anterior chamber.We advocate using a viscoelastic substancethat deepens the anterior chamber andstretches the anterior capsule. The use of aviscoelastic material accomplishes two im-portant goals:a) It creates space for safe instrumentation

in the anterior chamberb) By making the anterior capsule taut and

pushing the lens posteriorly it resists theaction of posterior pressure, which tendsto cause the capsular tear to move periph-erally


2. The tear is started at the centre of the cap-sule. This way the origin of the tear is includ-ed within the termination of the tear. Start-ing in the centre of the capsule generates aflap with a peripheral edge that is smoothand continuous

3. Once the initial flap is mobilized, it is invert-ed to permit a smooth tearing action, such aswould be achieved in tearing a piece of paperwith one half held stable while the invertedhalf is torn to the desired configuration. Thisprinciple is the same whether a cystotome/bent needle or forceps is used to create thecapsulotomy

4. The continuous tear proceeds either clock-wise or counter-clockwise in a controlledand deliberate fashion, the surgeon regrasp-ing with the forceps or repositioning thepoint of the cystotome/bent needle on the in-verted flap to control the vector of the tear.Upon completion of the CCC, it is essentialthat the origin of the peripheral portion ofthe CCC be included within the circumfer-ence of the tear

As we have indicated, it is essential to controlthe course of the capsular tear.A tear that beginsmoving peripherally or in a radial fashion is asignal that a condition exists that requires im-mediate attention. The first thing the surgeonmust do is to recognize the situation. Furtherprogress of the tear should be stopped and thedepth of the anterior chamber assessed. Fre-quently the cause of the peripheral course of thetear is shallowing of the anterior chamber andthe effect of posterior pressure on the lens andanterior capsule. Adding more viscoelastic todeepen the anterior chamber opposes the poste-rior pressure, makes the lens capsule taut,widens the pupil, and permits inspection of thecapsule to see whether zonular extension ontothe anterior capsule is responsible for the misdi-rection of the tear. Generally, the tear can beredirected and continued.

If the tear has extended peripherally andcannot be safely redirected, one option is to cre-ate a small tangential incision at the origin ofthe CCC with Vannas scissors and to direct thetear in the opposite direction to include the pe-ripheral extension. If this manoeuvre cannot be

accomplished and the discontinuity in the CCCremains, it is probably wisest to make severalother small incisions in the capsular rim so thatthe peripheral force is distributed evenly, reduc-ing the likelihood that a tear will extend aroundthe lens equator.

A similar situation may occur upon comple-tion of the CCC. Again, at this point it is essen-tial that the origin of the peripheral portion ofthe CCC be included within the circumferenceof the tear. If this manoeuvre is performed cor-rectly, it will result in a totally blended edge or it will form a small centripetally peaked area (cardioid). If the end of the CCC results in a V-shaped centrifugally oriented peak, however,this peak acts as a discontinuity in the anteriorcapsular opening and may extend peripherally,with the attendant consequences mentionedabove. The surgeon must convert this area to asmooth tear by either regrasping an edge to in-clude the V-shaped tear or by making a small in-cision with a Vannas scissors to create a seg-mental secondary CCC.

The use of a vital dye to stain the anteriorcapsule in the absence of a good red reflex con-stitutes an important adjunctive technique forcapsulorhexis construction. The surgeon makesthe sideport incision and then fills the anteriorchamber with air. The dye, either indocyaninegreen or trypan blue, is injected into the cham-ber. The air and residual dye is then exchangedfor viscoelastic. Despite the absence of a redreflex the capsule is now easy to see.

The technique of CCC has provided impor-tant advantages both for cataract surgery andIOL implantation. Because endolenticular or insitu phaco must be performed in the presence ofan intact continuous capsulotomy opening, thecapsulorhexis has also served as a stimulus formodification of phaco techniques.


∑ Critical elements of technique for the construction of continuous curvilinear capsulorhexis include operating in a deepand stable chamber, initiating the tear inthe centre of the capsule and regrasping the flap to maintain control of the vector of the tear at all times

2.3 Continuous Curvilinear Capsulorhexis 23

∑ The use of vital dyes has extended the application of continuous curvilinear capsulorhexis to cases with a reduced or absent red reflex

2.4Hydrodissection and Hydrodelineation

Hydrodissection of the nucleus in cataract sur-gery has traditionally been perceived as the in-jection of fluid into the cortical layer of the lensunder the lens capsule to separate the lens nu-cleus from the cortex and capsule [48]. With in-creased use of continuous curvilinear capsu-lorhexis and phacoemulsification in cataractsurgery, hydrodissection became a very impor-tant step to mobilize the nucleus within the cap-sule for disassembly and removal [10, 14, 26, 52].Following nuclear removal, cortical cleanupproceeded as a separate step, using an irrigationand aspiration handpiece.

Fine first described cortical cleaving hy-drodissection, which is a hydrodissection tech-nique designed to cleave the cortex from thelens capsule and thus leave the cortex attachedto the epinucleus [17]. Cortical cleaving hy-drodissection usually eliminates the need forcortical cleanup as a separate step in cataractsurgery, thereby eliminating the risk of capsularrupture during cortical cleanup.

2.4.1Cortical Cleaving Hydrodissection

A small capsulorhexis, of 5–5.5 mm, optimizesthe procedure. The large anterior capsular flapmakes this type of hydrodissection easier toperform. The anterior capsular flap is elevatedaway from the cortical material with a 26-gaugeblunt cannula (e.g. Katena Instruments No.K7–5150) prior to hydrodissection. The cannulamaintains the anterior capsule in a tented-upposition at the injection site near the lens equa-tor. Irrigation prior to elevation of the anteriorcapsule should be avoided because it will resultin transmission of a fluid wave circumferential-ly within the cortical layer, hydrating the cortexand creating a path of least resistance that will

disallow later cortical cleaving hydrodissection.Once the cannula is properly placed and theanterior capsule is elevated, gentle, continuousirrigation results in a fluid wave that passes cir-cumferentially in the zone just under the cap-sule, cleaving the cortex from the posterior cap-sule in most locations. When the fluid wave haspassed around the posterior aspect of the lens,the entire lens bulges forward because the fluidis trapped by the firm equatorial cortical-capsu-lar connections. The procedure creates, in effect,a temporary intraoperative version of capsularblock syndrome as seen by enlargement of thediameter of the capsulorhexis. At this point, iffluid injection is continued, a portion of the lensprolapses through the capsulorhexis. However, ifprior to prolapse the capsule is decompressed bydepressing the central portion of the lens withthe side of the cannula in a way that forces fluidto come around the lens equator from behind,the cortical-capsular connections in the capsu-lar fornix and under the anterior capsular flapare cleaved. The cleavage of cortex from the cap-sule equatorially and anteriorly allows fluid toexit from the capsular bag via the capsulorhexis,which constricts to its original size, and mobi-lizes the lens in such a way that it can spin freelywithin the capsular bag. Repeating the hydrodis-section and capsular decompression starting inthe opposite distal quadrant may be helpful. Ad-equate hydrodissection at this point is demon-strable by the ease with which the nuclear-corti-cal complex can be rotated by the cannula.

2.4.2Hydrodelineation

Hydrodelineation is a term first used by Anis todescribe the act of separating an outer epinu-clear shell or multiple shells from the centralcompact mass of inner nuclear material, the en-donucleus, by the forceful irrigation of fluid(balanced salt solution) into the mass of the nu-cleus [3].

The 26-gauge cannula is placed in the nucle-us,off centre to either side,and directed at an an-gle downward and forward towards the centralplane of the nucleus. When the nucleus starts tomove, the endonucleus has been rea-ched. It is


not penetrated by the cannula. At this point, thecannula is directed tangentially to the endonu-cleus, and a to-and-fro movement of the cannu-la is used to create a tract within the nucleus.Thecannula is backed out of the tract approximatelyhalfway, and a gentle but steady pressure on thesyringe allows fluid to enter the distal tract with-out resistance. Driven by the hydraulic force ofthe syringe, the fluid will find the path of least re-sistance, which is the junction between the en-donucleus and the epinucleus, and flow circum-ferentially in this contour. Most frequently, acircumferential golden ring will be seen outlin-ing the cleavage between the epinucleus and theendonucleus. Sometimes the ring will appear asa dark circle rather than a golden ring.

Occasionally, an arc will result and surroundapproximately one quadrant of the endonucle-us. In this instance, creating another tract thesame depth as the first but ending at one end ofthe arc, and injecting into the middle of the sec-ond tract, will extend that arc (usually anotherfull quadrant). This procedure can be repeateduntil a golden or dark ring verifies circumferen-tial division of the nucleus.

For very soft nuclei, the placement of thecannula allows creation of an epinuclear shell ofany thickness. The cannula may pass throughthe entire nucleus if it is soft enough, so theplacement of the tract and the location of the in-jection allow an epinuclear shell to be fashionedas desired. In very firm nuclei, one appears to beinjecting into the cortex on the anterior surfaceof the nucleus, and the golden ring will not beseen. However, a thin, hard epinuclear shell isachieved even in the most brunescent nuclei.That shell will offer the same protection as athicker epinucleus in a softer cataract.

Hydrodelineation circumferentially dividesthe nucleus and has many advantages. Circum-ferential division reduces the volume of the cen-tral portion of nucleus removed by phacoemul-sification by up to 50%. This allows less deepand less peripheral grooving and smaller, moreeasily mobilized quadrants after cracking orchopping. The epinucleus acts as a protectivecushion within which all of the chopping, crack-ing and phacoemulsification forces can be con-fined. In addition, the epinucleus keeps the bagon stretch throughout the procedure, making it

unlikely that a knuckle of capsule will come for-ward, occlude the phaco tip, and rupture.


∑ Critical steps of cortical cleaving hydrodis-section include injection of balanced saltsolution under the anterior capsule suchthat a fluid wave traverses the posterior aspect of the lens and decompression of the capsule by depression of the central portion of the lens

∑ Hydrodelineation means separation of the epinucleus from the endonucleus in order to allow the epinucleus to serve as a protective cushion during manipulation and extraction of the endonucleus

2.5Nucleofractis Techniques

The evolution of phaco from the initial proce-dure as described by Kelman [10] in the late1960s to the techniques that we currently prac-tice is nothing less than remarkable. The contri-butions of talented ophthalmic surgeons whopersevered throughout these years should becommended, since they laid the groundwork forour present methods.

The major distinction between the phacotechniques practised today and the earlier tech-niques is that modern methods have facilitatedphaco of dense cataracts within the capsularbag, allowing the central endonucleus to be re-moved before the epinucleus is encountered.With previous techniques, we worked from theperipheral portion of the epinucleus/nucleuscomplex toward the centre. This change was in-fluenced by the recognition that the nuclearmass of firm and hard lenses could be dividedinto smaller pieces for controlled removal with-in the protective layer of the epinucleus and thata capsular opening produced by a CCC wouldwithstand the forces involved in nuclear crack-ing. Retention of an intact CCC opening also re-quired sequential microsurgical removal of thecontents of the capsular bag, best achieved byperforming phaco in the central and deepestportion of the anterior chamber.

2.5 Nucleofractis Techniques 25

2.5.1Divide and Conquer Technique

Divide and conquer nucleofractis phaco, de-scribed by Gimbel [26], was the first nucleofrac-tis (two-instrument) cracking technique devel-oped. After adequate hydrodissection, a deepcrater is sculpted into the centre of the nucleus,leaving a dense peripheral rim that can later befractured into multiple sections. It is importantthat the crater include the posterior plate of thenucleus; otherwise, fracturing of the rim will bemuch more difficult. A shaving action is used tosculpt away the central nuclear material. Whenthe central material is no longer accessible tothe phaco probe, the lens should be rotated andadditional central phaco performed to enlargeand deepen the crater. The size of the centralcrater should be expanded for progressivelydenser nuclei. Enough of the dense materialmust be left in place, however, to allow the pha-co probe and second instrument to engage therim and fracture the lens into sections.

The surgeon uses his experience as a guide todetermine how deeply the central crater shouldbe sculpted. The peripheral nuclear rim stretch-es the entire capsular bag and acts as a safetymechanism to prevent the posterior capsulefrom suddenly moving anteriorly and being cutby the phaco probe.For harder nuclei, small sec-tions should be fractured from the rim. Ratherthan emulsify the sections as they are brokenaway, the sections should be left in place withinthe rim to maintain the circular rim and the ten-sion on the capsule. Leaving the sections inplace also facilitates rotation and the progres-sive fracturing of the remaining rim. It is some-times advisable to initially remove one smallsection to allow space for fracturing of the oth-er segments of the remaining rim. If only asmall fragment is removed, the remaining seg-ments can maintain capsular stretch and help toavoid rupture of the capsule. After the rim isfractured around the entirety of its circumfer-ence, each segment can then be brought to thecentre of the capsule for safe emulsification.One must be more cautious at this point be-cause as more segments are removed, less lensmaterial is available to expand the capsule and

the capsule will have a greater tendency to beaspirated into the phaco tip, especially if highaspiration flow rates are used.

2.5.2Phaco Fracture Technique

In phaco fracture, a widely used nucleofractistechnique described by Shepherd [53], the sur-geon sculpts a groove from the 12- to 6-o’clockposition after performing hydrodissection andhydrodelineation. The width of the grooveshould be one and a half to two times the diam-eter of the phaco tip. Using the phaco handpieceand a second instrument, the surgeon rotatesthe nucleus 90º. A second groove is sculptedperpendicular to the first, in the form of a cross.Sculpting continues until the red reflex is seenat the bottom of the grooves. Additional rota-tions and removal of nuclear material is oftennecessary to accomplish adequate grooving.Care should be taken to avoid sculpting com-pletely through to the cortex peripherally, sincethis puts the equatorial and posterior capsule atincreased risk of damage. A bimanual crackingtechnique is used to create a fracture throughthe nuclear rim in the plane of one of thegrooves.The nucleus is then rotated 90º,and ad-ditional fractures are made until four separatequadrants are isolated. The segments are thentumbled toward the centre of the capsule forsafe emulsification.A short burst of phaco pow-er is used to embed the phaco tip into the bulkof the isolated quadrant, and then with the useof aspiration, the quadrant is gently pulled intothe centre for emulsification. Alternatively, thesecond instrument can be used to elevate theapex of the wedge to facilitate mobilization ofthe nuclear quadrant to the capsule’s centre.


2.5.3Chip and Flip Technique

Introduced by Fine [14] and useful for softergrades of nuclei, this procedure relies on a nu-cleus that rotates freely within the capsular bag.Initially a central bowl is sculpted in the nucle-us until a thin central plate remains. The secondinstrument introduced through the side port in-cision engages the subincisional nuclear rim tomove the inferior nuclear rim to toward the cen-tre of the capsule bag. Then clock-hour pieces ofthe rim are carefully emulsified as the nucleus isrotated. Once the entire rim is removed, the sec-ond instrument is used to elevate the remainingcentral thinned nuclear plate (the chip), whichis then emulsified. The epinucleus is engaged atthe 6-o’clock position with aspiration alone. Asthe phaco tip is moved superiorly, the secondinstrument pushes the epinucleus toward the 6-o’clock position, thereby tumbling the epinu-clear bowl and permitting it to be aspirated (theflip).

2.5.4Crack and Flip Technique

Fine and colleagues modified Shepherd’s phacofracture technique by adding hydrodelineation,resulting in the crack and flip technique [22].Sculpting two deep grooves at right angles toeach other that extend to the golden ring per-mits bimanual nucleus cracking. Only theendonucleus cracks, since the epinucleus is sep-arated from it by hydro-delineation. Each quad-rant is then sequentially removed with the useof pulsed phaco and moderate aspiration. Thesecond instrument elevates the apices of eachquadrant so that the tip of the phaco needle canbe totally occluded to aid in aspiration. Once thenucleus is removed, the epinucleus is aspiratedas with the chip and flip technique.

There are several helpful tips in using thecrack and flip technique or a modification ofthis method. The sculpting portion of the pro-cedure is performed with minimal vacuum, rel-atively low aspiration flow, and low phaco pow-er. The forward passes of the phaco needle only

shave the nuclear material to ultimately sculpt agroove. The phaco tip is never totally occludedduring this phase of the operation. Rather, onlya portion of the phaco needle contacts the nu-cleus to remove controlled amounts of lensmaterial. This process is continued until thegrooves are deep. The appropriate depth can beassessed by a brightening of the red reflex,which suggests that the denser portion of thenucleus has been emulsified on the region of thegrooves.

To achieve nuclear cracking, two instru-ments are placed deeply in the grooves andmoved down and outward. The phaco needleand a second instrument introduced throughthe side port, paracentesis, or incision will crackthe nucleus if the grooves are sufficiently deepand the instruments placed in the depth of thegrooves. If cracking does not readily occur, ad-ditional deepening of the grooves is warranted.Phaco energy is not required during this step.The limit of the grooves is the golden ring,which represents the perimeter of the endonu-cleus. The loosened quadrants of the endonu-cleus remain within the cushion of the sur-rounding epinucleus.

Removing the nuclear fragments requires achange in the parameters for phaco. For thisstep, it is desirable to have lens material in con-tact with the phaco needle. Increasing the aspi-ration flow slightly directs lens material to thephaco tip, while increasing the vacuum encour-ages the nuclear fragments to be aspirated withapplication of only a minimum of phaco power.These parameters will be influenced by the den-sity of the nucleus, but in principle, these set-tings will result in successful nucleus removal.Asecond instrument guides the control of nuclearfragments.

Removing the epinucleus is accomplished asdescribed in Sect. 2.5.3. The parameters can bemodified such that: (1) the aspiration flow isslightly reduced from the setting used in nu-clear fragment removal, and (2) pulsed phacopower is used. If cortical cleaving hydrodissec-tion is successful, the cortex is removed alongwith the epinucleus during this step of the pro-cedure.


2.5.5Phaco Chop

The phaco chop technique was initially intro-duced by Nagahara, who used the natural faultlines in the lens nucleus to create cracks withoutcreating prior grooves (as presented by K. Naga-hara, at the American Society of Cataract andRefractive Surgery film festival, in 1993). Thephaco tip is embedded in the centre of the nu-cleus after the superficial cortex is aspirated. Asecond instrument, the phaco chopper, is thenpassed to the equator of the nucleus, beneaththe anterior capsule, and drawn to the phaco tipto fracture the nucleus. The two instruments areseparated to widen the crack. This procedure isrepeated until several small fragments are creat-ed, which are then emulsified.

Koch and Katzen [39] modified this proce-dure because they encountered difficulty in mo-bilizing the nuclear fragments. They created acentral groove or central crater, depending onthe density of the nucleus. This modificationpermits ease of removing the nuclear fragmentsliberated by the phaco chop technique.

Advocates of these nucleus-dividing tech-niques have suggested that high levels of vacu-um help to remove the nuclear fragments andminimize the need for ultrasound energy. Withsome of the newer phaco instruments, highervacuum power can be applied with minimalrisk of anterior chamber collapse.

2.5.6Choo Choo Chop and Flip

Fine described the “choo-choo chop and flip”technique in 1998 [20]. Subsequently, Fine,Packer and Hoffman correlated the reduction ofultrasound energy with this technique to im-provement in uncorrected post-operative dayone visual acuity [23]. A 30º standard beveldown tip is used throughout endonuclear re-moval. After aspirating the epinucleus uncov-ered by the capsulorhexis, a Fine/Nagaharachopper (Rhein Medical, Tampa, FL) is placed inthe golden ring by touching the centre of the nu-cleus with the tip and pushing it peripherally so

that it reflects the capsulorhexis. The chopper isused to stabilize the nucleus by lifting andpulling toward the incision slightly, after whichthe phaco tip lollipops the nucleus in eitherpulse mode at two pulses/s or 80-ms burst mode(Fig.2.1). Burst mode is a power modulation thatutilizes a fixed per cent power (panel control), aprogrammable burst width (duration of power),and a linear interval between bursts. As one en-ters foot position 3, the interval between burstsis 2 s; with increasing depressions of the footpedal in foot position 3 the interval shortens un-til at the bottom of foot position 3 there is con-tinuous phaco. In pulse mode, there is linearpower (%) but a fixed interval between pulses,resulting at two pulses/s in a 250-ms pulse (lin-ear power) followed by a 250-ms pause in pow-er followed by a 250-ms pulse, etc. However, inboth of these modulations with tip occlusion,vacuum is continuous throughout the pulse andpause intervals. With the energy delivered inthis way, ultrasound energy into the eye is min-imized and hold on the nucleus is maximized asvacuum builds between pulses or bursts. Be-cause of the decrease in cavitational energyaround the tip at this low pulse rate or in burstmode, the tunnel in the nucleus in which the tipis embedded fits the needle very tightly andgives us an excellent hold on the nucleus, thus


Fig. 2.1. The nucleus is stabilized during lollipop-ping for the initial chop

maximizing control of the nucleus as it is scoredand chopped in foot position 2 (Fig. 2.2).

The Fine/Nagahara chop instrument isgrooved on the horizontal arm close to the ver-tical “chop” element with the groove parallel tothe direction of the sharp edge of the vertical el-ement. In scoring the nucleus, the instrument isalways moved in the direction the sharp edge ofthe wedge-shaped vertical element is facing (asindicated by the groove on the instrument), thusfacilitating scoring. The nucleus is scored bybringing the chop instrument to the side of thephaco needle. It is chopped in half by pulling thechopper to the left and slightly down whilemoving the phaco needle, still in foot position 2,to the right and slightly up. Then the nuclearcomplex is rotated. The chop instrument isagain brought into the golden ring (Fig. 2.3), thenucleus is again lollipopped, scored, andchopped with the resulting pie-shaped segmentnow lollipopped on the phaco tip (Fig. 2.4). Thesegment is then evacuated utilizing high vacu-um and short bursts or pulse mode phaco at twopulses/s (Fig. 2.5). The nucleus is continuallyrotated so that pie-shaped segments can bescored, chopped, and removed essentially by thehigh vacuum assisted by short bursts or pulsesof phaco. The short bursts or pulses of ultra-sound energy continuously reshape the pie-

shaped segments which are kept at the tip, al-lowing for occlusion and extraction by the vac-uum. The size of the pie-shaped segments iscustomized to the density of the nucleus withsmaller segments for denser nuclei. Phaco inburst mode or at this low pulse rate sounds like“choo-choo-choo-choo”, ergo the name of thistechnique. With burst mode or the low pulse


Fig. 2.3. The nucleus is stabilized before the secondchop is commenced

Fig. 2.2. The initial chop is completed

Fig. 2.4. A pie-shaped segment adheres to the phacotip after the second chop is completed

rate, the nuclear material tends to stay at the tiprather than chatter as vacuum holds betweenpulses. The chop instrument is utilized to stuffthe segment into the tip or keep it down in theepinuclear shell.

After evacuation of the first hemi-nucleus,the second hemi-nucleus is rotated to the distalportion of the bag and the chop instrument sta-bilizes it while it is lollipopped. It is then scoredand chopped (Fig. 2.6). The pie-shaped seg-

ments can be chopped a second time to reducetheir size if they appear too large to easily evac-uate (Fig. 2.7).

There is little tendency for nuclear materialto come up into the anterior chamber with thistechnique. Usually it stays down within theepinuclear shell, but the chop instrument cancontrol the position of the endonuclear materi-al. The 30º bevel-down tip facilitates occlusion,as the angle of approach of the phaco tip to the


Fig. 2.5. The first pie-shaped segment is mobilized Fig. 2.6. The second heminucleus is scored

Fig. 2.7. The final quadrant is mobilized Fig. 2.8. The epinuclear shell is rotated for trimming

endonucleus through a clear corneal incision isapproximately 30º. This allows full vacuum tobe quickly reached which facilitates embeddingthe tip into the nucleus for chopping and allowsmobilization of pie-shaped segments fromabove rather than necessitating going deeperinto the endolenticular space as is necessarywith a bevel-up tip. In addition, the cavitationalenergy is directed downward toward the nucle-us rather than up toward the endothelium.

After evacuation of all endonuclear material,the epinuclear rim is trimmed in each of thethree quadrants, mobilizing cortex as well in thefollowing way (Fig. 2.8).As each quadrant of theepinuclear rim is rotated to the distal position inthe capsule and trimmed, the cortex in the adja-cent capsular fornix flows over the floor of theepinucleus and into the phaco tip. Then thefloor is pushed back to keep the bag on stretchuntil three of the four quadrants of the epinu-clear rim and forniceal cortex have been evacu-ated. It is important not to allow the epinucleusto flip too early, thus avoiding a large amount ofresidual cortex remaining after evacuation ofthe epinucleus.

The epinuclear rim of the fourth quadrant isthen used as a handle to flip the epinucleus(Fig. 2.9). As the remaining portion of the epin-uclear floor and rim is evacuated from the eye,most of the time the entire cortex is evacuated

with it. Downsized phaco tips with their in-creased resistance to flow are less capable ofmobilizing the cortex because of the decreasedminisurge accompanying the clearance of thetip when going from foot position 2 to foot po-sition 3 in trimming of the epinucleus.

After the intraocular lens is inserted, thesestrands and any residual viscoelastic materialare removed using the irrigation-aspiration tip,leaving a clean capsular bag.

If there is cortex remaining following re-moval of all the nucleus and epinucleus, thereare three options. The phacoemulsificationhandpiece can be left high in the anterior cham-ber while the second handpiece strokes the cor-tex-filled capsular fornices. Frequently, this re-sults in floating up of the cortical shell as asingle piece and its exit through the phacoemul-sification tip (in foot position two) because cor-tical cleaving hydrodissection has cleaved mostof the cortical capsular adhesions.

Alternatively, if one wishes to complete corti-cal cleanup with the irrigation-aspiration hand-piece prior to lens implantation, the residualcortex can almost always be mobilized as a sep-arate and discrete shell (reminiscent of theepinucleus) and removed without ever turningthe aspiration port down to face the posteriorcapsule.

The third option is to viscodissect the resid-ual cortex by injecting the viscoelastic throughthe posterior cortex onto the posterior capsule.We prefer the dispersive viscoelastic devicechondroitin sulfate-hyaluronate (Viscoat, AlconSurgical, Fort Worth, TX). The viscoelastic ma-terial spreads horizontally, elevating the poste-rior cortex and draping it over the anterior cap-sular flap. At the same time the peripheralcortex is forced into the capsular fornix. Theposterior capsule is then deepened with a cohe-sive viscoelastic device and the IOL is implant-ed through the capsulorhexis, leaving the ante-rior extension of the residual cortex anterior tothe IOL. Removal of residual viscoelastic mate-rial accompanies mobilization and aspiration ofresidual cortex anterior to the IOL, which pro-tects the posterior capsule, leaving a clean cap-sular bag.

Chop techniques substitute mechanicalforces (chopping) for ultrasound energy


Fig. 2.9. The epinucleus is flipped

(grooving) to disassemble the nucleus. Highvacuum is utilized as an extractive technique toremove nuclear material rather than utilizingultrasound energy to convert the nucleus to anemulsate that is evacuated by aspiration. Thesetechniques maximize safety, control and effi-ciency, allowing phaco of harder nuclei, even inthe presence of a compromised endothelium.Chop techniques facilitate the achievement oftwo goals: minimally invasive cataract surgeryand maximally rapid visual rehabilitation.

2.5.7Laser Phacoemulsification

Cataract extraction modalities employing laserenergy currently include the Erbium:YAG Pha-colase (Carl Zeiss Meditec, Jena, Germany),the Neodymium:YAG Photon Laser PhacoLysisSystem (Paradigm Medical, Salt Lake City) andthe Dodick Q-switched Neodymium:YAG laser(ARC GmbH, Jona, Switzerland). Several poten-tial advantages over ultrasound have main-tained interest in laser, including relative reduc-tion in the energy requirement for cataractextraction, the absence of any potential for ther-mal injury, and improved protection of cornealendothelial cells.

The erbium:YAG (2940-nm) laser energy iswell absorbed by tissues with high water con-tent and has a penetration depth of less than1mm. The laser energy is delivered via a fibre in-side the aspiration port placed flush with thetip. Hoh and Fischer demonstrated that erbiumlaser is safe and effective for mild to moderatenuclear sclerosis [34].

Surgeons may employ a bimanual technique,separating irrigation from aspiration, or themore familiar coaxial set up. With the latter,Takayuki Akahoshi’s counter prechop techniqueis used to effectively disassemble the lens nucle-us into multiple wedge-shaped segments [2]. Ahorizontal chopper such as the Fine-Nagaharachopper (Rhein Medical, Tampa, FL) is insertedvia the side-port, touched against the anteriorlens surface and gently pushed under the distalanterior capsular flap where it falls into thegolden ring. The chopper supports the nucleuswhile the Akahoshi Prechopper (ASICO, West-

mont, IL) is passed through the 2.5-mm cornealincision directly into the core of the nucleus.The chopper in the golden ring is held in frontof the prechopper to preclude rotational move-ment of the nucleus. Opening the prechopperthen bisects the nucleus.

The nucleus is then rotated 90º and the firsthemi-nucleus is bisected in a similar fashion.The chopper supports the hemi-nucleus fromthe golden ring while the prechopper is inserteddirectly into the centre of the hemi-nucleus andopened. In this manner the nucleus may be di-vided into four or more segments, each of whichis a suitable size for laser phacoemulsification.

Nd: YAG photolysis represents a low energymodality for cataract extraction developed byDodick [11]. Kanellopoulos reported a mean in-traocular energy use of 5.65 Joules per case [36].This level of energy compares favourably withvalues previously reported for ultrasound pha-coemulsification, and approximates the level ofenergy reported for the chop and flip pha-coemulsification technique using power modu-lations [49]. Huetz and Eckhardt found meantotal energy of 1.97 Joules for nuclear sclerosisup to grade 3, 3.37 Joules for Grade 3 and7.7 Joules for Grade 4 [35].

Surgeons generally employ a groove andcrack technique with the laser, sculpting in a bi-manual fashion and cracking as soon as possi-ble. Once superficial cortical material is aspirat-ed, the laser tip is used to ablate and fragmentthe nucleus. The laser tip should only just touchthe surface of the nucleus, and not be used toimpale the cataract. Following central photo-fragmentation, the nucleus is handled much asit is with the classic divide and conquer tech-nique. The total time that the tip is in the eyevaries with the grade of nucleus, from 2.15 minfor 1+ nuclear sclerosis to 9.8 min for 3+ nuclearsclerosis [36].

Using the bimanual Dodick system, acataract may be completely extracted throughtwo 1.5-mm incisions. Now, intraocular lenstechnology is becoming available to take advan-tage of this ultra-small incision. Wehner and Alihave reported a series of cases implanted with adehydrated acrylic intraocular lens through a1.5-mm incision [60].


2.5.8Bimanual Ultrasound Phacoemulsification

The promise of bimanual, ultra-small incisioncataract surgery and companion IOL technolo-gy is today becoming a reality, through bothlaser and new ultrasound power modulations.New instrumentation is available for bimanualsurgery, including forceps for construction ofthe capsulorhexis, irrigating choppers and bi-manual irrigation and aspiration sets. Propo-nents of performing phaco through two para-centesis-type incisions claim reduction ofsurgically induced astigmatism, improvedchamber stability in every step of the proce-dure, better followability due to the physicalseparation of infusion from ultrasound andvacuum, and greater ease of irrigation and aspi-ration with the elimination of one, hard-to-reach subincisional region. However, the risk ofthermal injury to the cornea from a vibratingbare phaco needle has posed a challenge to thedevelopment of this technique.

In the 1970s, Girard attempted to separate in-fusion from ultrasound and aspiration, butabandoned the procedure because of thermalinjury to the tissue [30, 31]. Shearing and col-leagues successfully performed ultrasound pha-co through two 1.0-mm incisions using a modi-fied anterior chamber maintainer and a phacotip without the irrigation sleeve [50]. They re-ported a series of 53 cases and found that phacotime, overall surgical time, total fluid use andendothelial cell loss were comparable to thosemeasured with their standard phaco tech-niques. Crozafon described the use of Teflon-coated phaco tips for bimanual high frequencypulsed phaco, and suggested that these tipswould reduce friction and therefore allow sur-gery with a sleeveless needle [9]. Tsuneoka, Shi-ba and Takahashi determined the feasibility ofusing a 1.4-mm (19-gauge) incision and a 20-gauge sleeveless ultrasound tip to perform pha-co [57]. They found that outflow around the tipthrough the incision provided adequate cool-ing, and performed this procedure in 637 caseswith no incidence of wound burn [58]. Addi-tionally, less surgically induced astigmatism de-veloped in the eyes operated with the bimanual

technique. Agarwal and colleagues developed abimanual technique, “Phakonit,” using an irri-gating chopper and a bare phaco needle passedthrough a 0.9 clear corneal incision [1]. Theyachieved adequate temperature control throughcontinuous infusion and use of “cooled bal-anced salt solution” poured over the phaco nee-dle.

Soscia, Howard and Olson have shown in ca-daver eye studies that phacoemulsification withthe Sovereign WhiteStar system (AMO, SantaAna,CA),using a bare 19-gauge aspiration needle,will not produce a wound burn at the highestenergy settings unless all infusion and aspira-tion are occluded [54, 55]. WhiteStar representsa power modulation of ultrasonic phacoemulsi-fication that virtually eliminates the productionof thermal energy. Referred to as “cold phaco,”WhiteStar allows reduction of the duration ofenergy pulses to the millisecond range.


∑ The divide and conquer technique employsultrasonic sculpting of a deep central craterand fracturing of segments of a peripheralrim

∑ Phaco fracture involves ultrasonic sculptingof grooves and bimanual cracking of thenucleus into four separate quadrants

∑ Chip and flip means sculpting of a centralbowl until a thin chip of endonucleus remains, while crack and flip is a modifica-tion of phaco fracture including hydrode-lineation

∑ Phaco chop requires a firm hold with highvacuum and a second sharp instrument toeither horizontally or vertically divide thenucleus

∑ Investigation of the choo choo chop and fliptechnique led to the conclusion that reduc-tion of ultrasound energy is correlated with improvement of visual acuity on thefirst postoperative day

∑ Phacoemulsification with laser systems allows reduction of incision size to 1.5 mm

∑ Surgeons using bimanual microincisionphacoemulsification have described improved chamber stability, better follow-ability and greater ease of irrigation and aspiration


2.6Conclusion

Since the time of Charles Kelman’s inspirationin the dentist’s chair (while having his teeth ul-trasonically cleaned), incremental advances inphacoemulsification technology have producedever-increasing benefits for patients withcataract. The modern procedure simply was notpossible even a few years ago, and until recentlyprolonged hospital stays were common aftercataract surgery.

The competitive business environment andthe wellspring of surgeons’ ingenuity continue todemonstrate synergistic activity in the improve-ment of surgical technique and technology. Fu-ture advances in cataract surgery will continueto benefit our patients as we develop new pha-coemulsification techniques and technology.

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surgical techniques for small incision cataract surgery 2

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