MICS Elevates the Quality of Cataract Surgery

How surgeons are making the move to smaller incisions

Dr. Wallace: At this point I would like to discuss the reasons why we have moved to smaller incisions for our cataract surgeries. Many surgeons today are operating through 2.2-mm incisions or 1.8-mm incisions, which Bausch + Lomb's Stellaris PC Vision Enhancement System and Akreos AO Micro Incision Lens allow us to do beautifully, either biaxially or coaxially. Some of us were using very large incisions in our practices in the past, 12 mm at one point! We have some obvious advantages for going smaller, such as less induced astigmatism, but what are some of the other benefits to small-incision surgery?

Dr. Weinkle: The fact that we can induce less astigmatism, or even be astigmatically neutral, by using small incisions has been well documented.^8-10 Other benefits of small-incision or MICS include the way smaller incisions seal more quickly and easily at the operating table. This is important because we're less likely to have wound leakage, which should reduce the risk of endophthalmitis. Also, in my experience, eyes are quieter with less inflammation postoperatively. A nice aspect of the Akreos lenses in particular is they don't seem to stretch the incision during implantation, which further facilitates secure wound sealing.

Dr. Silverstein: Smaller incisions allow us to enjoy much greater anterior chamber control with less trampolining of the capsule and a tighter relationship between the phaco instrument and sleeve relative to the wound. We don't need to over-expand the wound, and at the same time, we don't need to tear the collagen fibrils to get the instrument into the eye. Furthermore, to be able to control anterior chamber depth is a real advantage intraoperatively.

Dr. Malyugin: I think the main factor that's driving and limiting our incisions at this time is IOL technology. The IOL is the biggest object we introduce through the incision and it stretches the incision more than the instruments we use during surgery. So it's very important to improve the lens technology.

Right now, we're down to 1.8 mm and we see that it works and it doesn't introduce any unnecessary trauma because the incisions are sealing very well. However, progress in this direction, in my mind, will be directly connected with further progression of IOL technology.

Dr. Peters: When we moved to the 1.8-mm incisions in our practice, we did a small clinical trial to test and evaluate chamber stability and fluidics. I didn't change my phaco technique for the transition. We found that with 1.8-mm incisions, my phaco times were identical and my energy use was identical compared to larger incisions.

However, we also found that less fluid was used per case. The recovery of fluid in the cassette in the machine was statistically different than in the larger-incision cases. Not only were we losing less fluid, but more of it was coming back into the cassette, which suggests a closed chamber, and the closed chamber is what gives us stability.

Making the Transition to Smaller Incisions

Dr. Wallace: Some surgeons have really questioned whether 1.8-mm surgery is right for them. They feel it's quite a departure from their standard incision size and may significantly affect their phaco techniques. Certainly anterior capsulotomy is an issue they consider. Would they have to go back to using a needle? Can they really use capsulotomy forceps through such a tiny incision?

What have been your experiences in transitioning from standard incisions such as 2.8-mm or 2.75-mm down to 1.8 mm? Was the learning curve significant? Did you encounter many problems? Have you altered your techniques in order to be comfortable with a smaller incision size?

Dr. Peters: When the Akreos lens became available for 2.2-mm incisions, I began using that size incision. That was a small first step. At 2.2 mm, I used the exact same techniques, including the same Utrata forceps. That was more difficult than I wanted it to be, however, so I got thinner forceps, which made it much easier. When I changed to 1.8-mm incisions, I was still using those forceps, but I discovered that MST makes a great little capsulor-hexis forceps that goes through the 1.8-mm incision. Using those, I have extreme control — even in really shallow anterior chambers. It's possible to create a great capsulorhexis with standard techniques; it's just a different kind of forceps. It doesn't get oarlocked, visco-elastic doesn't come out of the incision when the forceps goes in, and iris doesn't prolapse out of the shallow eyes. In my opinion, it makes for a great rhexis.

Dr. Silverstein: Once we had the Akreos MICS lens, my initial trepidation was the difficulty of using standard cataract surgery instruments and manipulating them through the smaller incision. Initially, I did experience oarlocking and found it difficult to use my standard technique. I certainly didn't want to go backward in my comfort level, which I think makes many surgeons hesitant. Instead, I took the opportunity to design a series of MICS instruments for B+L Storz. I didn't derive any financial benefit — just the benefit of using the instruments.

One of the instruments we created is a long, slender pair of capsulorhexis forceps (Figure 1). They enable use of a standard technique and don't have any issues with manipulation or oarlocking. The anterior surface of the forceps is scored with a line denoting 5.5 mm and 6 mm from the end. This allows visualization of the diameter of the capsulorhexis in real time in vivo. We also developed a micro crystalline lens manipulator (Figure 2). It has a chopper on one end and a spatulated paddle on the opposite end to accommodate any phaco technique or density of lens material. It is easy to use through the 1.8-mm or even smaller incisions. In the past, I had difficulty going in and out of the wound with a standard J-style cannula for hydrodissection, so we designed a new version of that as well. It is a modernized version of the Wiles hydrodissection cannula. It is J-style and thin and allows easy passage through sub-2-mm wounds, while providing a good irrigating stream for hydrodissection, hydrodelineation and subincisional cortical clean up. Complementing the new instruments, of course, is the MICS handpiece (Figure 3) that comes with the Stellaris PC platform. We now have complete sets of readily available and inexpensive instrumentation, so we truly should have little-to-no learning curve for transitioning to MICS while using our preferred instruments.

Figure 1. Silverstein MICS 1.8-mm Capsulorhexis Forceps

Figure 2. Silverstein Phaco Manipulator & Quick Chop

Figure 3. The Stellaris System I/A Handle

Dr. Weinkle: I want to expand upon what Dr. Peters said about the lack of problems with reflux of viscoelastic or iris prolapse. MICS is particularly advantageous for patients who have taken tamsulosin or are at risk for intraoperative floppy iris syndrome (IFIS). It allows for a much more stable anterior chamber. Much less flow occurs around the silicone sleeve because of the architecture of the incision. MICS allows us to do more of these types of cases without having to use additional instrumentation.

Dr. Malyugin: When we talk about transitioning to MICS, we cannot say no transition at all is required. Two components are very important. The first component is the phaco machine. We do need some time to adjust to the platforms that are appropriate for MICS. We need to learn the machine.

The other component, as we have been discussing, is surgical technique. We all agree the time and effort required there, apart from maybe changing some instruments, is small. However, we have to be comfortable using our equipment and our machine, which definitely takes some time. I remember when I was learning to use the Millennium surgical system (Bausch + Lomb). I had to adjust to the dual linear foot pedal control, which was not accomplished instantly.

After that, however, I couldn't imagine how I would perform surgery without that feature. The point is that we do have to take some time to gain experience as we transition to MICS.

Dr. Weinkle: I have a suggestion for surgeons who are still using 2.2-mm or larger incisions. I suspect many of them consistently use keratomes that create a larger incision to accommodate subsequent IOL implantation. With standard phaco using a 2.2-mm or 2.3-mm incision, if you use a smaller blade width, you can complete the surgery with less fluidics and still implant an Akreos MICS lens without assistance through that small incision. I think there are many surgeons out there who could easily convert to smaller incisions without necessarily having to commit to 1.8-mm MICS and still experience the advantages of this lens. ■