The current trend in all surgical specialties is to decrease iatrogenic trauma by reducing the size of the incision. Cataract extraction has followed this same trend. Starting with the 12-mm incision used in cryoextraction just a few years ago, cataract incision sizes have quickly decreased, first to 9 mm for regular extracapsular cataract extraction, then to 3 mm for coaxial phacoemulsification, and now with microincision cataract surgery (MICS), to as small as 1.2 mm.
What is gained by transitioning to a smaller incision? Cataract surgery has evolved from a multiple-suture, in-patient procedure that was associated with induced astigmatism and a long period of wound instability into an ambulatory, sutureless procedure with practically immediate visual recovery.
At each step of the evolution, some voices have questioned the value of changing habits for a new technique. It is a fact that each step is associated with a sometimes stressful learning curve, and significant financial investment is usually required. But each advance has been followed by undisputably superior results.
Bimanual MICS (B-MICS) is indeed easier and safer than standard coaxial phacoemulsification. The anterior chamber remains stable, and the mode of ultrasound delivery reduces energy delivery. The benefit is better preservation of the corneal endothelium, resulting in a clear cornea postoperatively, even in patients with cornea guttata or a very hard nucleus.
There is still the question of the implant, however. So far, no IOL can be safely injected through a 1.2-mm incision. The minimum incision size is still 1.8 mm. But this size already offers a significant improvement to visual recovery. Compared to a 3-mm incision, a sub–2-mm incision is tighter and provides optical neutrality. I have no doubt that in the near future, the industry will provide new implants compatible with a small incision. From the beginning of the era of cataract surgery, it has always been the same story: Improvement of the cataract surgery procedure has always preceded advances in implants.
Herein, I describe my MICS technique. Surgery is performed under topical anesthesia. Two incisions of 1.2 mm are created; the first, a sideport incision, is made in the clear cornea, and the second is a small trapezoidal scleral tunnel. I use 23-gauge forceps (MicroSurgical Technology, Redmond, Washington) to perform the capsulorrhexis under VisCoat (Alcon Laboratories, Inc., Fort Worth, Texas) and Healon5 (Advanced Medical Optics, Inc., Santa Ana, California). I use the Signature phacoemulsifier with WhiteStar Increased Control and Efficiency (ICE; Advanced Medical Optics, Inc.). The irrigation tip (Lemagne Irrigating Spatula; Figure 1) and the aspiration tip used for cortex removal are components of the MicroSurgical Technology Duet System. After sculpting a central groove, the nucleus is cracked by opposing the irrigating tip and the phaco needle. The phaco needle engages the nuclear fragments, which are cut by the irrigating spatula (horizontal chop; Figure 2) and aspirated. After cortical cleaning, the scleral tunnel is enlarged to 1.8 mm and an Acri.Tec Acri.Smart 46 LC (Carl Zeiss Meditec AG, Jena, Germany) implant is injected into the bag. Viscoelactic is removed from the anterior chamber, and I then inject a small amount of Healon5 into the wound, acting like a cork to insure optimal watertightness. No patching is necessary, and the patient is instructed not to rub his eye.
I have found this technique to be the most effective in my hands. My transition to MICS has afforded me an easier and safer technique compared with standard coaxial phacoemulsification. I like performing B-MICS because of the stable anterior chamber and better preservation of the corneal endothelium, which results in a clear cornea postoperatively.
J.M. Lemagne, MD, is a Professor of Ophthalmology at the Catholic University of Louvain Medical School, Brussels, Belgium, and in private practice at the Ophthalmology Center, Brussels. Dr. Lemagne states that he has no financial interest in the products or companies mentioned. He may be reached at +32 475 25 91 85; jm.lemagne@skynet.be.
