EyeWorld Asia-Pacific December 2020 Issue

CATARACT EWAP DECEMBER 2020 33 by Maxine Lipner Contributing Writer Contact information MacDonald: susanmacdonaldeyecorps@gmail.com Vann: Robin.Vann@duke.edu This article originally appeared in the October 2020 issue of EyeWorld . It has been slightly modified and appears here with permission from the ASCRS Ophthalmic Services Corp. Optimizing manual small incision cataract surgery outcomes M anual small incision cataract surgery (MSICS) is a skill every cataract surgeon should learn, according to Susan MacDonald, MD. It gives a surgeon options and confidence to handle several complex cases, she said. With MSICS, there is limited risk to endothelial cells or dropping of the nucleus or fragments. Most importantly, it provides an excellent result without expensive technology, Dr. MacDonald said. There are several ways to maximize outcomes with this technique that is more commonly employed in areas where phaco is not a viable option. Minimizing astigmatism To maximize MSICS outcomes, is important to make an effort to minimize astigmatism. Dr. MacDonald stressed paying attention to preoperative astigmatism; it is possible to reduce astigmatism with the placement of the incision on the steep axis, she said. In a low resource setting, the Maloney Astigmatism Keratometer can help the surgeon evaluate the shape of the cornea at the beginning and end of the procedure. This will help the surgeon decide if a suture could help by placing it on the flat axis, she said. If using a scleral incision, this could be placed further away from the cornea where it will be less astigmatism-inducing. Reducing the size of the incision may help as well. Dr. MacDonald suggested modifying the MSICS using the miLOOP (Carl Zeiss Meditec) to create a 5 mm mini MSICS, a smaller incision, which can affect astigmatism. A recent prospective study considered another factor in minimizing astigmatism in MSICS: white-to-white measurements. 1 “We were trying to get a better handle on treating astigmatism,” said Robin Vann, MD, adding that when planning for small amounts of astigmatism with MSICS there were occasions where he was getting astigmatic surprises. He thought that possibly, akin to previous RK, arcuate, and limbal relaxing incisions, the closer these were to the visual axis, the greater their impact. Dr. Vann and co-investigators found, however, that this had minimal effect. “Despite my thinking about the white-to- white, at least in small incision cataract surgery where I was trying to make my incision very close to the limbus, whether it was temporally or superotemporally, this did not have any association,” Dr. Vann said, adding that other factors such as preoperative existing astigmatism, preoperative IOP, central corneal thickness, absolute length, number of paracentesis incisions, or the axis of the main incision weren’t statistically significant either. Mature white cataract. Small incision cataract surgery is performed by creating a 7–8 mm curvilinear half thickness scleral incision. The crescent blade is used to continue this incision forward, creating a pocket. The incision begins 1.5–2 mm posterior to the limbus and the pocket is made into the clear cornea by 1.5 mm. Source: Susan MacDonald, MD