Divide and conquer technique

Divide and conquer phaco, described by Gimbel2, was the first nucleofractis (two-instrument) cracking technique developed. After adequate hydrodissection, a deep crater is sculpted into the center of the nucleus, leaving a dense peripheral rim that can later be fractured into multiple sections. A shaving action is used to sculpt away the central nuclear material, and when this material is no longer accessible to the phaco probe, the lens should be rotated and additional central phaco performed to enlarge and deepen the crater. The size of the central crater should be expanded for progressively denser nuclei. Enough of the dense material must be left in place, however, to allow the phaco probe and second instrument to engage the rim and fracture the lens into sections. Notably, the peripheral nuclear rim stretches the entire capsular bag and acts as a safety mechanism to prevent the posterior capsule from suddenly moving anteriorly and being cut by the phaco probe. Once fractured, the lens sections should be left in place within the rim both to maintain the circular rim and to hold tension on the capsule rather than emulsifying them as they are broken away. Leaving the sections in place also facilitates rotation and the progressive fracturing of the remaining rim. After the rim is fractured around the entirety of its circumference, each segment can then be brought to the center of the capsule for safe emulsification.

Phaco fracture technique

In phaco fracture, a technique described by Shepherd3, the surgeon sculpts a groove from the 12- to 6-o’clock position after performing hydrodissection. Using the phaco handpiece and a second instrument, he or she then rotates the nucleus 90° and sculpts a second groove perpendicular to the first, in the form of a cross. Sculpting continues until the red reflex is seen at the base of the grooves, often requiring additional rotations and removal of nuclear material. At this point, a bimanual cracking technique is used to create a fracture through the nuclear rim in the plane of one of the grooves. The nucleus is then rotated 90°, and additional fractures are made until four separate quadrants are isolated. These are then tumbled toward the center of the capsule. A short burst of phaco power is used to embed the phaco tip into the bulk of the isolated quadrant and then, with the use of aspiration, the quadrant is gently pulled into the center for safe emulsification.

Chip and flip technique

Introduced by Fine4, and useful for softer grades of nuclei, this procedure relies on a nucleus that rotates freely within the capsular bag. Initially, a central bowl is sculpted in the nucleus until a thin central plate remains (the chip). The second instrument introduced through the side port incision engages the subincisional nuclear rim to move the inferior nuclear rim toward the center of the capsule bag. Clock-hour pieces of the rim are then carefully emulsified as the nucleus is rotated. Once the entire rim is removed, the second instrument is used to elevate the chip, which is then emulsified. The epinucleus is engaged at the 6-o’clock position with aspiration alone. As the phaco tip is moved superiorly, the second instrument pushes the epinucleus toward the 6-o’clock position thereby tumbling the epinuclear bowl and permitting it to be aspirated (the flip).

Crack and flip technique

Fine and colleagues modified Shepherd’s phaco fracture technique by adding hydrodelineation, resulting in the crack and flip technique4. Sculpting with minimal vacuum, relatively low aspiration flow, and low phaco power can be used to create two deep grooves at right angles to each other that extend to the golden ring, or the perimeter of the endonucleus, and permits bimanual nucleus cracking. Due to hydrodelineation of the epinucleus, only the endonucleus cracks.

To achieve nuclear cracking after hydrodelineation, two instruments are placed deeply in the grooves and moved down and outward. The phaco needle and a second instrument introduced through the side port, paracentesis, or incision will crack the nucleus if the grooves are sufficiently deep and the instruments placed in the depth of the grooves. If cracking does not readily occur, additional deepening of the grooves out to the golden ring is warranted and does not require phaco energy. The loosened quadrants of the endonucleus are then removed using altered phaco settings such that increasing aspiration flow directs the lens material to the phaco tip and increasing vacuum allows aspiration with minimal use of phaco power. A second instrument acts as a guide for control of the nuclear fragments. Lastly, and given successful hydrodissection, the epinucleus and cortex can be removed together during this step of the procedure as described in the chip and flip technique.

Phaco chop

The phaco chop technique was initially introduced by Nagahara, who used the natural fault lines in the lens nucleus to create cracks without creating prior grooves (Nagahara K, American Society of Cataract and Refractive Surgery Film Festival, 1993). The phaco tip is embedded in the center of the nucleus after the superficial cortex is aspirated. A second instrument, the phaco chopper, is then passed to the equator of the nucleus, beneath the anterior capsule, and drawn to the phaco tip to fracture the nucleus. The two instruments are separated to widen the crack. This procedure is repeated until several small fragments are created, which are then emulsified.

Koch and Katzen5 modified this procedure because they encountered difficulty in mobilizing the nuclear fragments. They created a central groove or central crater, depending on the density of the nucleus, which permits ease of removing the nuclear fragments liberated by the phaco chop technique.

Advocates of these nucleus-dividing techniques have suggested that high vacuum settings help remove the nuclear fragments and minimize the need for ultrasound energy. With some of the newer phaco instruments, higher vacuum power can be applied with minimal risk of anterior chamber collapse.

Choo choo chop and flip

Fine described the ‘choo choo chop and flip’ technique in 19986. Subsequently, Fine, Packer, and Hoffman correlated the reduction of ultrasound energy with this technique to improvement in uncorrected postoperative day one visual acuity7. A 30° standard bevel down tip is used throughout endonuclear removal. After aspirating the epinucleus uncovered by the capsulorrhexis, a Fine/Nagahara chopper (Rhein Medical, Tampa, FL) is placed in the golden ring by touching the center of the nucleus with the tip and pushing it peripherally so that it reflects the capsulorrhexis. The chopper is used to stabilize the nucleus by lifting and pulling toward the incision slightly (Fig. 13.1), after which the phaco tip lollipops the nucleus. This can be done in either pulse mode at 2 pulses/second or 80 millisecond burst mode.

Fig. 13.1 The Fine–Nagahara chopper supports the endonucleus as the phaco tip is advanced in foot position three and achieves a firm purchase.

Burst mode is a power modulation that utilizes a fixed percentage power, a programmable burst width, and a linear interval between bursts. Phaco in burst mode or at this low pulse rate sounds like ‘choo-choo-choo-choo’; therefore, the name of this technique. With the energy delivered in this way, ultrasound energy into the eye is minimized and hold on the nucleus is maximized as vacuum builds between pulses or bursts. Because of the decrease in cavitational energy around the tip at this low pulse rate or in burst mode, the tunnel in the nucleus in which the tip is embedded fits the needle very tightly and allows excellent hold on the nucleus, thus maximizing control of the nucleus as it is scored and chopped (Fig. 13.2).The nucleus is scored by bringing the Fine/Nagahara chop instrument to the side of the phaco needle. It is chopped in half by pulling the chopper to the left and slightly down while moving the phaco needle to the right and slightly up. Then the nuclear complex is rotated. The chop instrument is again brought into the golden ring (Fig. 13.3), and the nucleus lollipopped, scored, and finally chopped with the resulting pie-shaped segment now lollipopped on the phaco tip (Fig. 13.4). The segment is then evacuated utilizing high vacuum and short bursts or pulse-mode phaco at 2 pulses/second. The nucleus is continually rotated so that pie-shaped segments, the size of which is driven by the density of the cataract, can be scored, chopped, and removed easily by the high vacuum and assisted by short bursts or pulses of phaco (Fig. 13.5).

Fig. 13.2 Vacuum is maintained in foot position 2 as the chopper is brought to the side of the phaco tip and the two instruments are separated, hemisecting the endonucleus.

Fig. 13.3 Following rotation of the endonuclear complex, the chopper is repositioned in the golden ring and the phaco tip is buried in the distal heminucleus in preparation for the second chop.

Fig. 13.4 The second chop is complete. The pie-shaped wedge of nucleus is positioned on the phaco tip, ready for aspiration by high vacuum and small pulses of ultrasound as required. The size of this wedge can be adjusted in inverse proportion to the density of the cataract.

Fig. 13.5 An additional chop may be taken in the pie-shaped wedge if its density is relatively high.

After complete evacuation of the first heminucleus, the second heminucleus is rotated to the distal portion of the bag and the chop instrument stabilizes it while it is lollipopped. It is then scored and chopped (Fig. 13.6). The pie-shaped segments can be chopped a second time to reduce their size (Fig. 13.7) if they appear too large to easily evacuate.

Fig. 13.6 After extraction of the first heminucleus, the remaining material is rotated distally and chopped.

Fig. 13.7 The final pie-shaped wedge is chopped and extracted.

After evacuation of all endonuclear material, the epinuclear rim is trimmed in each of the three quadrants, mobilizing cortex as well. As each quadrant of the epinuclear rim is rotated to the distal position in the capsule and trimmed, the cortex in the adjacent capsular fornix flows over the floor of the epinucleus and into the phaco tip. The floor is then pushed back to keep the bag stretched until three of the four quadrants of the epinuclear rim and forniceal cortex have been evacuated while not permitting the epinucleus to flip too early. This prevents retaining a large amount of residual cortex after epinuclear evacuation. The epinuclear rim of the fourth quadrant is then used as a handle to flip the epinucleus (Fig. 13.8). As the remaining portion of the epinuclear floor and rim is evacuated from the eye, most of the time the entire cortex is evacuated with it.

Fig. 13.8 The epinucleus is grasped distally and flipped over, facilitating aspiration.

After the IOL is inserted, remaining strands of cortex and any residual viscoelastic material are removed using the irrigation-aspiration tip, leaving a clean capsular bag.

If there is cortex remaining following removal of all the nucleus and epinucleus, there are three options. First, the phacoemulsification handpiece can be left high in the anterior chamber while the second handpiece strokes the cortex-filled capsular fornices. Alternatively, if one wishes to complete cortical clean-up with the irrigation-aspiration handpiece before lens implantation, the residual cortex can almost always be mobilized as a separate and discrete shell and removed without ever turning the aspiration port down to face the posterior capsule.

The third option is to viscodissect the residual cortex by injecting the viscoelastic through the posterior cortex onto the posterior capsule. The viscoelastic material spreads horizontally, elevating the posterior cortex and draping it over the anterior capsular flap. At the same time, the peripheral cortex is forced into the capsular fornix. The posterior capsule is then deepened with a cohesive viscoelastic device, and the IOL is implanted through the capsulorrhexis, leaving the anterior extension of the residual cortex anterior to the IOL. Removal of residual viscoelastic material accompanies mobilization and aspiration of residual cortex anterior to the IOL, which protects the posterior capsule, leaving a clean capsular bag.

Ultimately, chop techniques maximize safety, control, and efficiency, allowing phaco of harder nuclei, thereby facilitating the achievement of two goals: minimally invasive cataract surgery and maximally rapid visual rehabilitation.

Biaxial micro incision cataract surgery (B-MICS)

The historical development of biaxial micro incision cataract surgery began in the 1970s when Girard attempted to separate infusion from ultrasound and aspiration, but abandoned the procedure because of thermal injury to the tissue8,9. Shearing and colleagues successfully performed ultrasound phaco through two 1.0 mm incisions using a modified anterior chamber maintainer and a phaco tip without the irrigation sleeve10. They reported a series of 53 cases and found that phaco time, overall surgical time, total fluid use, and endothelial cell loss were comparable to those measured with their standard phaco techniques. Crozafon described the use of Teflon-coated phaco tips for bimanual high frequency pulsed phaco, and suggested that these tips would reduce friction and therefore allow surgery with a sleeveless needle11. Tsuneoka, Shiba, and Takahashi determined the feasibility of using a 1.4 mm (19-gauge) incision and a 20-gauge sleeveless ultrasound tip to perform phaco12. They found that outflow around the tip through the incision provided adequate cooling, and performed this procedure in 637 cases with no incidence of wound burn13. Additionally, less surgically induced astigmatism developed in the eyes operated with the bimanual technique. Agarwal and colleagues developed a bimanual technique, ‘Phakonit’, using an irrigating chopper and a bare phaco needle passed through a 0.9 clear corneal incision14. They achieved adequate temperature control through continuous infusion and use of ‘cooled balanced salt solution’ poured over the phaco needle.

Soscia, Howard, and Olson have shown in cadaver eye studies that phacoemulsification with the Sovereign WhiteStar system (AMO, Santa Ana, California), using a bare 19-gauge aspiration needle, does not produce a wound burn at the highest energy settings unless all infusion and aspiration are occluded due to the limited duration of energy pulses this technology delivers15,16.

There are many advantages of biaxial micro incision cataract surgery (B-MICS). These include enhanced chamber stability thanks to a more nearly perfectly closed system, better followability due to separation of infusion and aspiration, and access to 360° of the anterior segment with either infusion or aspiration by switching instruments from one hand to the other. Furthermore, it permits using the flow of irrigation fluid as a tool to move material within the capsular bag or anterior chamber, prevention of iris billowing and prolapse in cases of intraoperative floppy iris syndrome, and significantly decreased chance of vitreous prolapse in the case of a posterior capsular tear, zonular dialysis, or subluxed cataracts, thanks to maintenance of a pressurized stream of irrigation from above.

Separation of irrigation from the aspirating phaco needle allows for improved followability by avoiding competing currents at the tip of the needle. In some instances, the irrigation flow from the second handpiece can be used as a gentle adjunctive surgical device – flushing nuclear pieces from the angle or loosening epinuclear or cortical material from the capsular bag while minimizing trauma to delicate intraocular structures. In refractive lens exchange the lens material may be washed completely out of the bag and extracted with aspiration and vacuum only, so that no ultrasound is used and no instrument enters the endocapsular space, increasing the safety profile of this demanding procedure17.

A separate infusion stream is also beneficial when scrubbing troublesome plaques from the posterior capsule (Fig. 13.9). Focusing the flow of fluid on the posterior capsule and putting the tissue on stretch facilitates capsule polishing with either a roughened or silicone-covered aspiration tip without entrapping the taut posterior capsule.

Fig. 13.9 Utilizing Xenon slit beam illumination (Carl Zeiss Meditec, Dublin, CA) highlights this posterior subcapsular plaque. The stream of irrigation fluid from the irrigating chopper is directed posteriorly to put the capsule on stretch while the silicone sleeved aspiration tip is used to scrub away the material.

Perhaps the greatest advantage of the biaxial technique lies in its ability to remove subincisional cortex without difficulty. Brauweiler originally described switching infusion and aspiration hand pieces between two microincisions as a means of reaching 360° of the capsular fornices and making cortical clean-up quick and safe18. The ability to switch hands is also a significant advantage to instructors, who may find they must take over a case from a resident with opposite manual dominance.

Utilization of B-MICS offers an enormous advantage of maintaining a more stable intraocular environment during lens removal. This may be especially important in high myopes who are at a greater risk for retinal detachment following lens extraction. By maintaining a formed and pressurized anterior chamber throughout the procedure, there should be fewer tendencies for anterior movement of the vitreous body with a theoretical lower incidence of posterior vitreous detachment occurring from intraoperative manipulations, although future studies in this regard are warranted.

Finally, B-MICS is advantageous when intraoperative floppy iris syndrome (IFIS) occurs. Keeping the irrigator high in the anterior chamber tamponades the iris and keeps it from becoming floppy. As long as we irrigate above the iris, it will not billow. Alternatively, we can hydroexpress the cataract out of the capsular bag and carousel the endonucleus in the plane of the capsulorrhexis, so that the epinucleus holds the iris back. In those IFIS cases where we cannot hydroexpress the lens, we dilate the pupil widely with Healon 5 (Abbott Medical Optics, Inc., Santa Ana, California), do our hydrosteps, and then perform one endolenticular chop. Next, we bring the nuclear material up to the irrigating chopper, which is kept above the iris, for disassembly and mobilization. The pupil can be redilated with Healon 5 in the case of constriction following epinucleus removal. By keeping the aspiration tip in occlusion, we go circumferentially around the capsulorrhexis, mobilizing cortex from the capsular fornices without bringing it out of the eye. Maintaining occlusion of the tip immobilizes Healon 5, thus allowing the pupil to remain dilated. After the cortex has been removed from the fornix, we then remove it from the eye.

While the advantages described above relate principally to separation of irrigation from aspiration, some of the other major advantages of B-MICS relate to incision size. For example, there has been an improvement in control of most of the steps involved in endocapsular surgery due to increase chamber stability. Since viscoelastics do not leave the eye easily through these small incisions, the anterior chamber is more stable during capsulorrhexis construction and there is much less likelihood for an errant rhexis to develop. This added margin of safety is particularly noticeable in cases of zonular compromise such as PXF, traumatic zonular dialysis and after glaucoma filtering surgery, as well as in cases of intumescent cataract and nanophthalmos with a very shallow anterior chamber (Figs 13.10 and 13.11). The added chamber stability can also make a difference in control of the capsulorrhexis in high myopia with an extremely deep anterior chamber and floppy capsule. Hydrodelineation and hydrodissection can also be performed more efficiently by virtue of a higher level of pressure building in the anterior chamber prior to eventual prolapse of viscoelastic through the microincisions.

Fig. 13.10 The capsulorrhexis is nearly complete in this eye with a history of trauma and 90° of zonular dialysis visible temporally. The wrinkling of the capsule is a clear sign of absent tension. Nevertheless, because of the increased control allowed by the microincisions which do not allow prolapse of viscoelastic, the capsulorrhexis will be centered, round, and smaller in diameter than the IOL.

Fig. 13.11 Capsular dye and microincisions help to control the capsulorrhexis in this eye with a hypermature cataract.

In order to reap the benefit of these advantages, strict attention to detail is required. The first technique to master is construction of the incision. There is variability in incision size depending on the gauge of instrumentation used. We prefer 20-gauge because we feel it offers greater control. Because the outer diameter of the 20-gauge tip is 0.9 mm, the circumference of the tip is 2.8 mm and the incision must measure 1.4 mm. An incision smaller than 1.4 mm stretches and tears, causing loss of self-sealability. These microincisions are converted from a line to a circle upon introduction of the tip, and we want them to resume the configuration of a line when the tip is withdrawn. Compromise of the corneal collagen by stretching or tearing will reduce the likelihood that the incision will resume its virgin architecture at the end of the case. This can be minimized by using only trapezoidal-shaped incisions.

Capsulorrhexis construction represents a significant hurdle in the biaxial learning curve. However, microincision capsulorrhexis forceps permit a greater degree of precision and control, so much so that we advocate their use with any size of incision. The pinch type initiation of the capsulorrhexis is particularly valuable in cases of zonular compromise since the forces acting on the capsule remain balanced. Even with a severely wrinkling capsule due to traumatic zonular dialysis, these extraordinarily delicate forceps permit moment-by-moment control of the capsulorrhexis. This is important because capsulorrhexis size is an important determinant of final lens position and therefore postoperative refractive status. Using microincisions enhances the precision of capsulorrhexis construction not only because of the improvements in instrumentation, but also because there is not a tendency for the chamber to shallow as often occurs with a 2.5 mm incision due to release of viscoelastic.

As stated previously, the goal of cortical cleaving hydrodissection is to lyse the equatorial capsular-cortical connections, which will generally allow aspiration of the cortex, along with the mobilization of the epinucleus. Hydrodelineation is performed to allow free mobility of the endonucleus within the epinuclear shell, allowing endocapsular nuclear disassembly within the safety cushion of the epinucleus. Hydrodissection and hydrodelineation may be performed just as described above for standard small incision surgery; the microincisions do allow egress of viscoelastic during this step so that there is not an increased risk of blowing out the posterior capsule due to over-pressurization. Of note, we found that the intraocular pressure during hydrodissection, as measured in the vitreous cavity of a cadaver eye, varies around means of 78–223 mmHg regardless of whether a standard small incision or microincision is employed19. These were among the highest pressures we recorded during the entire phacoemulsification and IOL implantation procedure. Clearly, if viscoelastic is prevented from exiting the eye there is adequate pressure to rupture the capsule. This represents a special concern to users of high zero shear viscosity OVDs, who should ensure that a path for egress is prepared with a track of balanced salt solution from the cannula tip to the incision.

The surprising fact about horizontal and vertical chopping techniques with biaxial phaco is how little they differ in terms of hand movement from standard small incision coaxial phaco. Seeing the bulkier irrigating chopper in the eye and getting used to the heavier feel in one’s hand represent the major differences; the actual chopping techniques are the same. The stream of irrigation fluid from the chopper or manipulator can function as an efficient tool within the eye and is one of the most significant advantages of biaxial phaco, a key reason to abandon coaxial. In particular, washing subincisional endo- or epinuclear material into range of the phaco tip permits enhanced safety and control. An example is refractive lens exchange (RLE) with an accommodative IOL in high myopia, probably the situation in which we are most concerned about maintaining the integrity of the capsule. Not only would compromising the capsule increase the risk of posterior segment complications, but it may also result in an inability to implant the IOL of choice for the procedure. With biaxial RLE no instrument other than a cannula and a stream of fluid ever need enter the endolenticular, or endocapsular space; we can hydroexpress the soft lens material into the anterior chamber with the stream of irrigation fluid and carousel it safely from the eye with fluidics alone17. Cortical cleaving hydrodissection achieves a clean capsule without ever placing an aspiration tip below the level of the capsulorrhexis, and the absence of ultrasound energy allows for the safest, most minimally invasive procedure possible, both exemplifying the enhanced margin of safety with this approach.

If there is a breach of the posterior capsule, however, residual lens material can generally be removed while maintaining irrigation in the anterior chamber and preventing vitreous prolapse. With biaxial phaco it is possible to switch from a phaco tip to an aspirator to a vitrector if necessary without ever compromising chamber stability. The approach, once a tear is recognized, consists of continuous irrigation in the anterior chamber while lens material is removed from the bag. Once the bag is clean, a dispersive viscoelastic is injected at the level of the posterior capsule while irrigation is still maintained; only once the viscoelastic has fully tamponaded the break and filled the chamber is the irrigator removed. The IOL can then be inserted into the ciliary sulcus or the capsule through a standard temporal clear corneal incision. In the case of sulcus placement the optic is pushed posteriorly through the capsulorrhexis prior to final clean-up. Once viscoelastic is removed, the triamcinolone staining technique described by Burk and colleagues is utilized to ensure a completely vitreous-free environment in the anterior segment20.

We have found this technique to be simple, efficacious, and safe since most of the lens extraction is occurring in the plane of the iris, away from the posterior capsule and the corneal endothelium. Nevertheless, details are very important with this technique as it is not very forgiving. Consider these concepts in beginning to apply B-MICS:

Examining each step in a model case enhances understanding. Following hydrodissection and hydrodelineation, the phaco needle is first embedded proximally with high vacuum and 40% power (Table 13.1). In the left hand is a vertical chopper which will be used to split the nucleus in two. As vacuum builds to occlusion a rapid rise time enables the phaco needle to quickly grasp the endonucleus. At the point occlusion is reached the aspiration flow rate drops to zero. We then move into foot position two so that high vacuum is maintained and the power goes to zero (Fig. 13.12). The blade of the irrigating vertical chopper is brought down just distal to the phaco tip as we lift up slightly with the phaco needle. As a full thickness cleavage plane develops, dividing the nucleus in two, we separate our hands to ensure a complete chop (Fig. 13.13).

*ICE: Increased control efficiency.

**Case – [replaces occlusion mode when selected] – (Chamber stabilization environment).

Up threshold: 70%.

Down threshold: 50%.

Up time: 500 msec.

Fig. 13.12 The 20-gauge phaco needle is embedded in the endonucleus as the irrigating chopper is prepared to incise and split the lens.

Fig. 13.13 The nucleus is divided to the right and left. In this case a posterior shelf has developed; it is particularly important to separate the instruments fully to insure a complete chop in this situation.

The lens can then be rotated with the irrigating chopper so that the first heminucleus can be chopped and consumed. If there is a disparity in size, the larger half is moved distally and a quadrant size piece is chopped off and consumed (Fig. 13.14). The remaining quadrant of the first heminucleus is then impaled with the phaco tip and aspirated (Fig. 13.15). Total effective phaco time (EPT), or the amount of time that ultrasound would have been turned on had it been running on 100% continuous power, is a useful parameter to follow and to this point was less than half a second. That means that we used about half a second of the maximum ultrasound power that the machine can produce to remove half of the nucleus thereby minimizing thermal injury and maximizing safety.

Fig. 13.14 After a second chop has divided one of the heminuclei, the first quadrant is mobilized.

Fig. 13.15 The irrigating chopper is used to hold epinucleus back as another quadrant is aspirated.

The second half of the nucleus is next addressed by rotating it with the irrigating chopper so that it is in the distal capsule. The phaco needle is embedded in the smaller heminucleus which is then subdivided with the irrigating chopper, again using high vacuum and low levels of power (Fig. 13.16). As the final quadrant is grasped and pulled centrally for aspiration, the sharp blade of the irrigating chopper is turned sideways as a safety precaution (Fig. 13.17).

Fig. 13.16 A segment of the second heminucleus is aspirated.

Fig. 13.17 As the final quadrant is aspirated the chopper is turned sideways and the flow of irrigation fluid is directed posteriorly to keep the posterior capsule at safe distance.

When addressing the epinucleus, we reduce our settings, turn down the vacuum and flow rate and trim the rim of the epinucleus, preventing the epinucleus from flipping into the phaco needle with the stream of irrigation fluid or the irrigating chopper itself. The advantage of the trimming procedure lies in the aspiration of cortical material from behind the epinuclear shell. In most cases this step eliminates the need for I/A prior to IOL insertion. Once three quadrants of the epinuclear shell have been rotated and trimmed the final quadrant is used to flip the epinuclear bowl into the phaco needle (Fig. 13.18). Following aspiration of the epinucleus the capsule is entirely clean of cortex (Fig. 13.19). In conclusion, B-MICS with a vertical chop technique allows efficient lens extraction with rapid visual rehabilitation. This procedure demonstrates some of the tangible benefits of separating inflow from outflow, use of irrigation fluid as an instrument to mobilize material, and reduced Effective Phaco Time.

Fig. 13.18 The epinucleus is grasped with the phaco needle at reduced power, flow, and vacuum and flipped.

Fig. 13.19 The capsule is clean; asteroid hyalosis is visible in the vitreous cavity.