Since the advent of phacoemulsification, surgeons have been developing innovative ways to break up and remove the cataract. Some like horizontal chopping, while others prefer techniques like divide-and-conquer. Here, cataract surgeons describe their favorite techniques, as well as how they adjust these approaches based on the density of the cataract.
Horizontal Quick Chop
Sumit (Sam) Garg, MD, who is in practice in Irvine, California, primarily uses a horizontal quick-chop technique for nuclear disassembly. He first uses the phaco probe to impale the nucleus. Then, he uses a Seibel chopper to go around the equator of the lens and chop the nucleus in half, then into quarters or sixths, depending on the density of the lens.
“That’s my go-to,” says Dr. Garg. “When I graduated from training, I was very comfortable with stop-and-chop, which I think is still a very useful technique for difficult lenses. And, sometimes if the lens is really tough, I’ll go back to stop-and-chop, which involves using the phaco probe to create a groove centrally, and then cracking that groove in half. Then, you move to chop. But, at that point, you’ve already divided the nucleus into two, so the chopping becomes a little easier.”
He adds that one of the advantages of the horizontal quick-chop technique is that it delivers less phaco energy into the eye. “Additionally, in my experience, it’s a little more efficient with respect to time, so I’m able to accomplish nuclear disassembly in just a few seconds,” Dr. Garg says. “However, surgeons who use divide-and-conquer can be really fast, too, so I think it’s sort of a wash at the end of the day. But I learned chopping and, to me, chopping makes a lot more sense than burrowing out or bowling out a cataract. And so, if you can break up a cataract mechanically using less energy and fluid, that intuitively makes sense to me. Also, I’m a big fan of using my second instrument to help move things around and bring pieces closer to the phaco tip and trying to keep the phaco tip near the center of the eye for most of the case.”
James Davison, MD, who is in practice in Des Moines, Iowa, uses different techniques for different types of cataracts. He uses the LOCS III grading system, which was developed in 1993 by Leo Chylack, MD, at Harvard.1 This system grades cataracts on nuclear opalescence (NO; scale from 0.1 to 6.9), nuclear color (NC; scale from 0.1 to 6.9), cortical spoking and posterior subcapsular area (P). “If the NO and the NC are 3.6 or less, then we know the nucleus is soft enough to use an Akahoshi prechopper to divide the lens into quarters and then remove it,” Dr. Davison explains.
For medium-firm lenses (LOCS III NO and NC 3.7 to 3.8), he uses a divide-and-conquer technique. “We like to use a Connor wand for these because some of these lenses are a little bit softer, and the cyclodialysis spatula will sink into the nuclear substance as it’s pushed against it when tearing the posterior nuclear plate,” explains Dr. Davison. “The Connor wand will give you a little more vertical surface area to push on the face of the nucleus to crack it. So, we use the 45-degree Balanced Tip to sculpt our grooves, then we use the Connor wand to break the nucleus into quarters, and then we shave away the remaining firm corners, all in the sculpt setting. So, we remove as much of the hard material as we can while the nucleus is in the capsular bag, and then we turn the machine to epinucleus or quadrant removal settings and bring the relatively thin two-dimensional pieces into the empty nuclear bowl to remove them.”
A Connor wand isn’t needed for firmer cataracts (LOCS III NO and NC 3.9 or higher). “We use a cyclodialysis spatula that’s been modified from 0.5-mm to 0.35-mm diameter,” Dr. Davison says. “It seems to be just right for cracking the posterior plate and maneuvering the nucleus and then its fragments.” Surgeons say a dispersive viscoeleastic helps facilitate these maneuvers.
When the chop technique was introduced in 1994, Dr. Davison performed it using several different instruments. However, after trying several variations, he found that the corneas were just not as clear with that technique. “I got some Descemet’s folds, but I hardly ever get them with any of the divide-and-conquer techniques,” he says. “I found that my endothelial cell loss rate for relatively hard cataracts was 2.7 percent.2 So, for me and my skill set, the way I’ve been trained, and the way I’ve worked, it’s been better for me and better for the patients to use the divide-and-conquer techniques. The chop technique typically doesn’t require as much ultrasonic energy from the machine, but it depends on higher levels of vacuum to aspirate nuclear fragments, so you can get really low ultrasonic energy use times and amounts with that technique, but you have to bring up the piece that you break off into the iris plane and anterior chamber to remove it. You can get a little more generous and keep it away from the cornea in the later pieces that you break off and aspirate, but for the first pieces, you have to bring them into the anterior chamber to remove them. Although it’s a little faster and has lower energy consumption measured on the machine, the corneas look better if I just do the divide-and-conquer technique.”
Horizontal and Vertical Chop
Richard Hoffman, MD, who practices in Eugene, Oregon, performs bimanual phaco and uses a chopping technique for nuclear disassembly. He performs horizontal chopping for softer lenses and vertical chopping for denser lenses. “I basically hydrodissect and hydrodelineate the lens into an endonucleus, an epinucleus and the cortex,” Dr. Hoffman explains. “Then, I remove the endonucleus using a chopping technique and use the epinucleus as a buffer between the phaco needle and the posterior capsule. Next, I remove the epinucleus and then the cortex. However, many times, as I’m removing the epinucleus, if I’ve done cortical cleaving hydrodissection, the cortex comes with the epinucleus.”
Dr. Hoffman uses irrigating choppers and has moved from 20-gauge to 21-gauge because the phaco needles are now 21-gauge. “It’s a 21-gauge irrigator with a chopping element on the bottom end of the irrigator,” he adds.
Dr. Hoffman notes that there are advantages to a bimanual technique. “We prefer that technique,” he says. “When new doctors come into our practice and switch from coaxial to bimanual, they seem to like it. It is important to remember that the smaller the incision, the less induced astigmatism, and the safer the eye is from blunt trauma. Another advantage of bimanual is its I/A. If you’re performing bimanual phaco, it’s very easy to use bimanual I/A, and that makes removal of the cortex much easier than doing it coaxially.”
Additionally, he says that a bimanual technique is advantageous in certain challenging cases where you might not want to rotate the lens. “By doing the procedure bimanually, you have access to the lens from two different directions,” Dr. Hoffman says, “so you can actually switch the phaco handpiece and the irrigator between the incisions. It’s really nice for posterior polar cataracts and for IFIS patients because you can have infusion from your second handpiece kept above the level of the iris. This results in a lot less billowing of the iris.”
Dr. Garg advises surgeons to use different techniques for different types of cataracts. “Some cataracts don’t require as much chopping,” he notes. “I think it’s important for people to know about other possible techniques, but also to have one go-to that they feel most comfortable doing for the majority of their cases. If you have that repetition, then you get really good at that one technique.”
He adds that it is important to remember to protect the cornea, especially in cases involving dense lenses. Dr. Garg uses a dispersive viscoelastic to make sure that the endothelium stays protected. “Then, you can always use the same viscoelastic in the bag if the bag is floppy,” he says. “If you’re unable to get pieces to move around, you can always put a little viscoelastic into the capsular bag to help keep it stretched a little bit. Then, use your second instrument to move pieces toward you or move a piece that’s stuck. Often, we go after those with our phaco handpiece, but, when you’re vacuuming, even if you’re not in phaco, you have a higher chance of damaging the capsular bag than you do with a blunt instrument.”
Dr. Davison also believes that all of the current techniques are good choices, so surgeons should choose the technique they’re most comfortable with, as long as they take care when working on the last section of nucleus and use enough viscoelastic. “I put in more before the last quadrant if the lenses are firm because I think there’s probably more damage done to the last quadrant than anything else,” he says. “You use the shell of the nucleus that’s remaining to protect the posterior capsule while you’re breaking up the fragment that you’re working on. But, when you’re down to the last quadrant, there’s nothing to protect the posterior capsule. The surgeon, fearing capsule disruption or capsule aspiration, moves everything closer to the cornea in the iris plane. So, you are almost always very close to the cornea when you’re taking out that last piece. And if it’s a big, hard piece, you can really rattle it around and bang up the cornea when you do that. This is why it’s important to add more [viscoelastic] before removing the fourth quadrant.”
Dr. Garg notes that companies and surgeons are exploring techniques that don’t rely on phaco to remove cataracts. “The miLoop (Carl Zeiss Meditec) is helpful to remove really dense lenses, and some people advocate using that for all cases,” he says.
A study published earlier this year (albeit by researchers with financial interests in the miLoop) found that microinterventional endocapsular fragmentation with the manual, disposable miLoop device provided consistent, ultrasound-free, full-thickness nucleus disassembly.3
This prospective, single-masked, multisurgeon, interventional, randomized controlled trial was conducted to assess the safety and efficacy of microinterventional endocapsular nuclear fragmentation in moderate to severe cataracts. It included 101 eyes of 101 patients with grade 3 to 4+ nuclear cataracts. Eyes were randomized to torsional phacoemulsification alone (controls) or torsional phacoemulsification with adjunctive endocapsular nuclear fragmentation using a miLoop. Outcome measures included phaco efficiency as measured by ultrasound energy (cumulative dispersed energy), fluidics requirements (total irrigation fluid used) and the incidence of intraoperative and postoperative complications.
For this study, only high-grade advanced cataracts were enrolled. More than 85 percent of eyes in both groups had a baseline best-corrected visual acuity of 20/200 or worse. Mean CDE was 53 percent higher in controls (32.8 ±24.9 vs 21.4 ±13.1) than in patients in the miLoop group. Endothelial cell loss after surgery was low and was similar between the groups (7 to 8 percent).
One month postoperatively, best-corrected visual acuity averaged 20/27 Snellen in the miLoop eyes and 20/24 in control eyes. Intraoperative and postoperative complication rates were comparable between the groups; however, there was a trend toward a lower rate of capsular tear during the phaco portion of the procedure with miLoop-assisted phaco (7.5 percent) compared with standard phaco (10.4 percent). One eye in the miLoop-assisted group experienced a capsular tear related to the intraocular lens inserter when implanting the intraocular lens.
Dr. Garg notes, however, that it will be difficult to stop relying on phaco for cataract procedures. “There’s some thought that some of the newer technologies may be able to move us away from phaco,” he says, “but something’s going to have to be really dramatic and really efficient to move us in that direction.” REVIEW
Dr. Garg consults for Johnson & Johnson Vision and Dr. Davison consults for Alcon. Dr. Hoffman has no financial interest in any product discussed.
1. Chylack LT Jr, Wolfe JK, Singer DM, et al. The Lens Opacities Classification System III: The longitudinal study of Cataract Surgery Group. Arch Ophthalmol 1993;111:831-836.
2. Davison JA. Results of endocapsular phacofracture debulking of hard cataracts. Clin Ophthalmol 2015;9:1233-1238.
3. Ianchulev T, Chang DF, Koo E, et al. Microinterventional endocapsular nucleus disassembly: Novel technique and results of first-in-human randomised controlled study. British Journal of Ophthalmology 2019;103:2:176-180.