Eyeworld

EW CATARACT 38 January 2018 Device focus by Michelle Stephenson EyeWorld Contributing Writer Alternatives to femtosecond lasers are entering the marketplace N ew devices for cataract surgery are entering the marketplace that have benefits over femtosecond lasers for capsulotomies, according to some surgeons. "One of the benefits of the femtosecond laser is that it provides a perfectly round, perfectly centered capsulo- tomy," said Mark Packer, MD, Boul- der, Colorado. "However, scanning electron micrographs of that cut edge of the femtosecond capsuloto- my have shown that it looks craggy and irregular, and capsular strength testing has shown that femtosecond laser capsulotomies are not as strong and resistant to tearing as manual capsulotomies." Several companies have begun looking at ways to make a perfectly round capsulotomy that is stronger than a femtosecond laser capsu- lotomy and is less expensive than buying a femtosecond laser. Zepto The Zepto capsulotomy system (Mynosys Cellular Devices, Fremont, California) is a device for making a capsulotomy. It consists of a thin nitinol wire loop, which is the element that gets hot and does the cutting. The loop is surrounded by a silicone plastic shell connected to a suction tube. "The idea is that you introduce this into the eye through a 2.2-mm to 2.4-mm incision," Dr. Packer said. "The silicone shell squeezes down. There's a push rod inside the silicone sleeve that you use to expand the ring to a circle, and nitinol has shape memory, so it goes back to a circle. You pull that push rod out, retract the push rod, turn on the suction, and the whole thing sucks itself down onto the anterior capsule. The manufacturer talks about being able to align this device using the first and third Pur- kinje reflexes, so you're close to the line of sight in the center. We then turn on the suction, send a jolt of electricity through, cut the capsulo- tomy, release the suction, and pull it out. In pulling the device out, the corneal wound compresses the sili- cone shell, so you come out through that same small wound." According to Dr. Packer, preclin- ical studies have shown that Zepto capsulotomies are stronger than manual capsulotomies, which are stronger than laser capsulotomies. Additionally, it is perfectly round. The device received 510K clearance this year and is available now. "The price is $175 for the disposable. The handpiece under the ring is all one unit with a cord that plugs into a box," Dr. Packer said. "The box is a $10,000 capital purchase, which is significantly less than a laser, but the reusable cost of $175 is a little high for standard cat- aract surgery. I think there are two places where it may be used. One is in difficult and challenging cases for standard surgery, and the other is in the premium refractive cataract surgery cases, where it might take the place of a femtosecond laser." ApertureCTC ApertureCTC (International Bio- Medical Devices, Mt. Pleasant, South Carolina) is following in the footsteps of Zepto. "The technology is somewhat similar in that it's a thermal device that creates the cap- sulotomy with heating," Dr. Packer said. "Key differences are that the tip design is stainless steel and does not require suction; it has two com- pressible stainless steel blades that form a perfect circle. When they're in the elongated position, they can be introduced through a 2.2-mm incision. There's a little slide on the handpiece, which compresses the blades, and they form a circle. A current is run through the blades, which creates heat, and cuts the capsule tissue in milliseconds. There is no suction, however, the thermal heating element is insulated from the anterior chamber environment. The anterior chamber is filled with viscoelastic during the procedure." ApertureCTC is still in preclin- ical stages of development, with a goal of using it in humans for the first time next year. CAPSULaser CAPSULaser (Los Gatos, California) is a completely different concept. It's a laser device that is a microscope attachment. "The laser is small and fits onto the bottom of the oper- ating microscope," said Richard Packard, MD, Windsor, U.K. "It can perform capsular openings from 4.5 mm to 6.5 mm. The capsular open- ing is created in 1 second following staining of the anterior capsule with a new formulation of trypan blue. In clinical studies of more than 400 patients, there have been 100% free capsulotomy caps and no anterior capsule tear-outs. Comparing the results of accuracy of sizing, circular- ity, and centration on the visual axis to published data on femtosecond and manual capsulotomies shows a clear advantage for CAPSULaser." miLOOP miLOOP (Iantech, Reno, Nevada) is an endocapsular, nitinol ring that acts like a snare that bisects the cataract and chops the cata- ract into smaller pieces. "It's also an alternative or supplement to the femtosecond laser that can be used in complex cataracts, such as very dense cataracts," said William Wiley, MD, Cleveland. "One of its unique advantages is that it truly bisects the cataract from equator to equator, even behind a small pupil. In contrast, the femtosecond can only laser what it sees. So even with a femtosecond laser, when you use softening mode, you don't get a full softening or a full dissection of the cataract. The miLoop bisects the cataract completely in half from equator to equator and even smaller pieces if you deploy it multiple times." It has the ability to make the surgery easier by dismantling the lens and mobilizing the fragment- ed pieces making them easier to aspirate. It also decreases ultrasound energy levels inside the eye in dens- er cataracts, which allows for faster healing and fewer complications. "I see this being applied in a number of different ways," Dr. Wiley said. "It could be applied for complex cas- es. For example, if there is a dense cataract and you need to make the case easier by bisecting it, the miLOOP can be used there. Further- more, it can be utilized in premium cases when you're looking for faster New devices in cataract surgery The ApertureCTC device is deployed on the anterior capsule in preparation for capsulotomy construction. Source: Mark Packer, MD This image of the miLOOP shows the loop deployed in the open position, which can be retracted or closed with the finger le- ver, resulting in an efficient and effective modality to transect the nucleus. Source: William Wiley, MD CAPSULaser device attached under an operating microscope Source: Richard Packard, MD Zepto capsulotomy system console Source: Mynosys Cellular Devices

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