Since its introduction over 60 years ago, the basic idea behind phacoemulsification has not changed: a vibrating ultrasonic tip creates microscopic cavitation bubbles that expand, oscillate, and contract, ultimately creating thermal energy as a byproduct of the mechanical and cavitation forces. Numerous iterative advances in the technology since then have helped improve the safety profile of this technology. However, what has not changed are the inherent limitations associated with the use of thermal energy in this manner, namely the potential for heat transfer that can induce damage to ocular tissue, including the delicate endothelium.
The MICOR 700 (ZEISS) introduces a completely new mechanism for cataract extraction (Figure 1). The device, a self-contained handpiece that does not require a base unit, uses asymmetric oscillation—rapid forward motion followed by a slower retraction—to avoid creation of cavitation energy and achieve mechanical fragmentation of a cataract. Operating without ultrasound energy at 40 Hz, it delivers a thousand-fold less energy than standard phacoemulsification (Figure 2).
Figure 1. The MICOR 700 is a handheld lens extraction device that operates ultrasound free.
Figure 2. Use of the MICOR 700 for lens extraction yields no temperature increase over a 4-minute procedure.
Designed with a blunt and rounded tip design, the MICOR 700 is engineered to be more delicate in contact with ocular tissue than conventional phaco tips. Plus, because there is no base unit and no foot pedal, capital expenditures are minimized, setup time is reduced, and surgeons achieve improved ergonomics in the OR.
In the following, three surgeons who were early adopters of MICOR 700 discuss their initial experience and offer tips for its implementation.
The Learning Curve With MICOR 700 | Seth Pantanelli, MD, MS
The reason I adopted MICOR 700 is because I was intrigued by the technology, wanted to be part of the innovation, and believed it could help me achieve better outcomes for my patients. My experience has borne that belief out. I recently analyzed my first 100 cases with MICOR, comparing them to cases previously completed with phacoemulsification (unpublished data). In the MICOR cases, I used less BSS per case (about 30 ccs/case) compared to phacoemulsification (60–100 ccs/case). Lens extraction was about 45 to 60 seconds faster with MICOR, which was surprising to me, because I have performed phacoemulsification for about 10 years. And last, MICOR patients had better day-1 postoperative vision compared with phacoemulsification.
All told, learning to use the MICOR 700 for lens extraction took me about 5 to 10 cases, and I felt fully proficient with the device by the time I had completed my first 50 cases. However, there are some nuances to performing lens removal with the MICOR. First, the MICOR 700 does not sculpt the lens; instead, it requires the surgeon to pre-chop the lens. For soft nuclei, I manually pre-chop using a Nagahara, and for medium-density lenses, I use the miLOOP (ZEISS), which is complementary to the MICOR in minimizing the need for ultrasonic energy. Other surgeons have reported using femtosecond laser nucleus disassembly or a pre-chopper (eg, an Akahoshi pre-chopper) for this step.
Additionally, MICOR uses a higher vacuum (about 600-650 mm Hg) than what I am used to with phacoemulsification, so instead of grabbing epinucleus and flipping the quadrant up to extract, I instead grab the center of each quadrant before pulling it up. I/A is also slightly different. With phacoemulsification, we are trained to go to the periphery, grab a wedge, pull it to the center, and then increase vacuum. With MICOR, you don’t have to go out to the periphery and sweep to obtain occlusion; instead, you stay close to the edge of the capsulorrhexis, angle the I/A tip toward the capsular bag equator, and increase vacuum. The cortical wedges just come to the tip.
From my perspective, learning to perform cataract extraction with the MICOR 700 is well within the skillset of any anterior segment ophthalmic surgeon, and the transition is greatly facilitated for those already familiar with pre-chopping a lens.
Advantages Relative to Phacoemulsification | Yousuf M. Khalifa, MD, FACS
In my hands, the MICOR 700 (ZEISS) is a game changer for cataract extraction for appropriately selected patients. Over the course of my experience using this technology, I have noticed some important differences compared to traditional phacoemulsification:
- Improved ergonomics. Because there is no foot pedal (the action of the handpiece is controlled with a finger switch), it is both easier to position the patient and to find a comfortable working position in the OR.
- Enhanced capsular bag safety. I have grabbed bags with the MICOR tip and not broken them because MICOR operates at a much lower frequency than a phaco tip, and because the design of the tip is rounded. To date, I have experienced one posterior capsule rupture while using MICOR, but the extent of damage was limited; the blunted tip created only a small circular patch that did not extend.
- Faster setup. All that is needed to operate with the MICOR 700 is the handpiece, which is attached to a disposable tip, and an irrigation bottle that is hung on an IV pole. Compared to phacoemulsification, there are fewer instrumentation requirements, the setup and teardown are faster, and sterilization needs are minimized. In all, the setup takes about 5 minutes, which means faster turnover for the OR room (and, anecdotally, happier staff).
- Excellent cataract removal efficiency. Because there is less ultrasound energy compared to phacoemulsification, chatter is reduced, and the followability of lenticular fragments is enhanced. There is an important caveat, however: MICOR 700 is best suited for use with soft and medium-density cataracts.
Applications for MICOR 700: MIGS Patients and Beyond | Neel Desai, MD
The MICOR 700 (ZEISS) is broadly applicable in eyes with a soft to medium-density cataract. However, there are a few patient types for whom this technology may have some advantages over traditional phacoemulsification.
We use MICOR in eyes receiving advanced-technology IOLs because we believe it helps deliver a premium experience. The day-1 postoperative vision after a MICOR procedure is unparalleled, which only helps us in meeting patients’ expectations for excellent vision. Plus, it’s great to be able to tell patients that we are using a device that will be gentler on their eye compared to traditional phacoemulsification.
One of my essential-use cases is in patients with Fuchs dystrophy, or really any compromised cornea. Using MICOR in these eyes gives me confidence that I am doing everything I can to protect the delicate endothelium. Additionally, because the vacuum is controlled proximal to the eye in the handpiece, I don’t really experience any post-occlusion surge like I do with some phacoemulsification platforms, where the fluidics are controlled through meters of compliant tubing.
Another example is in MIGS cases combined with cataract surgery. In my thinking, MICOR really solves the debate about whether to do the cataract extraction and lens placement first or second in the procedure. With MICOR, I am confident that I will be able to extract the lens and keep a clear cornea, so I have the proper visualization to perform the MIGS portion of the procedure at the end.
We are currently in the planning phases of adding office-based surgery in two of our offices, and we are planning to introduce MICOR for these setups, primarily because we don’t have a large footprint to allow for a base unit and a femtosecond laser, but also because it will require far less capital expenditure when we build out the spaces. We have little doubt that as we expand our office-based surgery offering, we will find additional applications for using MICOR, including for refractive lens exchange and even potentially for use in bilateral, same-day surgery.
