EyeWorld India December 2020 Issue

EWAP DECEMBER 2020 15 FEATURE the latter is incomplete—the laser leaves a 500–800 µm offset from the posterior capsule, leaving the nuclear plate intact. This expensive machine, he said, still leaves incomplete nuclear division. So, Dr. Yeoh decided to give prechop another go. Using a paddle prechopper that he modified from an old design by Dr. Akahoshi, Dr. Yeoh found the direct prechop “very, very effective” and he decided to revisit its use for cataracts on the softer end of the density spectrum. Nuclear paradox “Bear in mind that the crux of nuclear management in phaco is to ensure complete separation of nuclear segments which is something that prechop does very well,” Dr. Yeoh said. “Now for a dense nucleus this is very straightforward, your nucleus is hard enough, you can push, you can crack, you can divide it very easily, but it’s these softer nuclei that are paradoxically harder to separate. “Softer nuclei, he said, are a challenge.” Softer nuclei are harder to rotate, grip, and crack, he said. “This is where I believe prechop should reign.” Dr. Yeoh said the karate prechop is “arguably a better or more elegant technique” than stop and chop on soft nuclei. He believes the technique is particularly relevant because in the age of refractive cataract surgery, it counts to have a technique that lowers the complication rate and aids in delivering perfect refractive outcomes. In the age of refractive cataract surgery, he said, he sees two main groups of patients: The normal age-related cataract patients with denser cataracts, and a new group of patients in their 50s and 60s with softer, “neither here nor there” cataracts. “I believe that direct prechop is the perfect technique for these soft nuclei,” he said. Karate complications Dr. Yeoh admits complications are still possible with karate prechop. If the nucleus is too hard, attempting a karate prechop could inflict zonular damage. These cases necessitate a nucleus sustainer. If your anterior chamber is not deep enough, the surgeon can damage the endothelium with the instrument. If the surgeon pushes the instrument too deep, in theory, a posterior capsule rupture could occur, although Dr. Yeoh has never experienced this. More recently, Dr. Yeoh has found the use of a new Akahoshi Combo 4 prechopper (Asico, 2018–2019) produced radial tears. The Combo 2, he said, was one of the best original designs. While limited to NS++, he never had subincisional radial tears using this chopper. The Combo 4 chopper is sharper, thinner, with a longer straight cutting edge that could be used to prechop up to NS+++, but Dr. Yeoh had a run of four cases with subincisional radial tears. However, Dr. Akahoshi—who Dr. Yeoh said does 5,000 cases a year—said he has never seen this complication. Dr. Yeoh theorized that it was the Combo 4’s straight, sharp edge that was damaging the rhexis edge when rotating the nucleus with the instrument or when prechopping the proximal heminucleus, especially near the incision, especially if the capsulorhexis is small to begin with. Dr. Yeoh redesigned the Combo 4 prechopper into what he calls the Safer 1 prechopper, halving the straight sharp edge of the Combo 4. With the first prototype, he found the was hinge too large, and so redesigned it to be slimmer—the Safer 2 prechopper (Figure 2). Considering the choice of prechopper for karate prechop, Dr. Yeoh said that the classic Combo 2 is good for general use up to NS++; the Combo 4 is good up to NS+++, but should be used with a large, central capsulorhexis; the Safer 2 is good up to NS+++ or a small pupil and/or capsulorhexis. So while the technique is ideal for those “neither here nor there” cataracts Dr. Yeoh Figure 2. Three different prechoppers. Dr. Yeoh redesigned Dr. Akahoshi’s Combo 4 prechopper, producing the two Safer prechoppers. Source: Ronald Yeoh, MD described, new chopper designs allow the technique to be used for up to NS+++ cataracts; however, denser cataracts require the counter prechop. Rescue chop Finally, Dr. Yeoh described how prechopping can also come to the rescue in certain situations. He described a case in which the nucleus would not crack with stop and chop. The situation was saved by using direct prechop. “We’ve come full circle,” Dr. Yeoh said. “From femtolaser prechop, I came to appreciate that the prechop technique is wonderful and the direct prechop I think is a great technique to add to your armamentarium so you can address the full range of cataracts from the soft to the intermediate to the dense very, very effectively.” EWAP Editors’ note: Dr. Yeoh has interests with J&J Vision, Alcon, and Zeiss. Reference 1. Akahoshi T. Phaco Prechop: Manual Nucleofracture Prior to Phacoemulsification. Operative Techniques in Cataract & Refractive Surgery. 1998;1(2).