Eyeworld

62 | EYEWORLD | JUNE 2022 ATARACT C Figure 9. Intraoperative OCT finds retained nuclear lens fragment. Figure 10. FLACS fragmentation pattern imaged with intraoperative OCT Source (all): Ronald Yeoh, MD Contact Miller: kmiller@ucla.edu Vasavada: icirc@abhayvasavada.com Yeoh: ersryeoh@gmail.com He said that these are brief but important steps in phaco. "In Figure 4, we can see that after hydrodissection, there is a layer of fluid behind the nucleus with a small layer of residual lens cortex still present in front of the posterior cap- sule. Despite our best efforts to effect cortical cleaving hydrodissection, leaving a clean poste- rior capsule, this is often difficult to achieve," he said. "Hydrodelineation, which was also done in this case, results in a golden ring around a small nucleus, and this is reflected by the intraoper- ative OCT image of a thin line just behind the nucleus." Intraoperative OCT can also identify if there is still OVD under the IOL (Figures 5 and 6). As a surgical aid, Dr. Yeoh shared a case where intraoperative OCT was able to detect and show a posterior capsule rupture prior to starting surgery (Figure 7), which allowed the surgeon to modify the technique. Dr. Yeoh also shared how he was able to image patients with anterior radial tears and posterior capsule ruptures, thanks to intraoper- ative OCT, when corneal clarity compromised the view or was just difficult to see. "The intact posterior capsule is transparent and difficult to see even with a microscope, and sometimes we are unsure as to whether a posterior capsule rupture has occurred," he said. Figure 8 shows a patient who had an ante- rior radial tear in the capsulorhexis edge and an anterior radial tear extending posteriorly across the whole posterior capsule. "The anterior radial tear is shown by the two thick, curved lines and the posterior capsule tear by the thinner and more scrolled edges. I named this the 'intraoperative OCT scroll sign of posterior capsule rupture,'" he said. "They behave differently because we know that the anterior capsule is thicker than the posterior." Intraoperative OCT also came to the rescue when a patient was brought back to the OR with a retained nuclear lens fragment. Intraop- erative OCT was able to find the fragment in the angle for successful removal (Figure 9). Dr. Yeoh used imaging from intraoperative OCT to show why less ultrasound energy is needed in FLACS with dense cataracts. "I prefer to use a laser grid pattern with two horizontal cuts, which effectively softens the nucleus for easy division and removal using less ultrasound energy. In Figure 10, we can see how the grid pattern with horizontal cuts results in little rectangular 'chips,' explaining why less ultrasound energy is needed," he said. Dr. Yeoh said that while intraoperative OCT was initially considered a "nice to have" feature for cataract surgery, he thinks it's finding a bigger role in training, surgical decision mak- ing, research around wound construction and integrity, IOL positioning, and removal of OVD. "From an institutional point of view, having cataract surgeons use this technology in cataract surgery makes its acquisition a more economical proposition than just being for corneal or vitreo- retinal surgeons' use," he said. continued from page 61

• Cover