Eyeworld

EW REFRACTIVE 50 June 2018 by Stefanie Petrou Binder, MD, EyeWorld Contributing Writer Presentation spotlight reduced visualization of the intra- ocular structures and more bleeding because of increased vascularization. There is a higher risk of conjunctival ballooning during the surgery, espe- cially if you are in training. Tempo- ral incisions allow easier access and are much further from the center. They have better visualization of the intraocular structures. Also, longer tunnels are possible with less bleed- ing and ballooning." Incisional funnel Landmarks can help the surgeon place incisions that keep him or her in the safe zone. The incisional funnel is a virtual safe area where incisions can be placed with mini- mal effect on the corneal curvature, making them astigmatically stable. Overall, incisions made closer to the limbus, such as might result from superior incisions, are likely to cause more astigmatism. Short incisions made close to the limbus or longer incision further from the limbus, such as temporal incisions, are better to avoid astigmatism. A study that compared temporal and superior incisions revealed significantly lower astigmatism with temporal incisions, compared to eyes with superior incisions. 2 Blade purity and sharpness "The sharper your blade, the more control you have, with reduced trauma and reproducible cuts. The harder the material, the sharper the blade," Dr. Muftuoglu said. "Hard- ness varies greatly among materials from stainless steel to synthetic dia- monds. There are different types of diamond blades, which are usually thin and very sharp, so the surgeon should bear in mind that he or she may also have an increased risk of catching the capsule." While the quality of diamond blades is usually very good, Dr. Muftuoglu alerted surgeons to be informed about the composition of their steel blades, for instance flat- tened wire or flat stock steel, which represent different qualities. There is also great variability in the quality and consistency of metal blades from one manufacturer to anoth- er, and surgeons should examine blade design, size, length, and blade Incisions and astigmatism continued on page 52 Incisional funnel Mindful wound placement can have a telling effect on cataract surgical outcomes I ncision shape and placement, blade choice, and personal preferences are all factors that contribute to wound creation and collectively determine the effect it will have on reducing or inducing astigmatism in a patient's cornea. According to Orkun Muftuog- lu, MD, professor of ophthalmology, Koc University School of Medi- cine, Istanbul, Turkey, who gave a presentation on creating the perfect wound and correcting astigmatism at the 2018 ESCRS Winter Meeting, creating incisions in cataract surgery is a vital step. Incisions can be corneal or scleral, and choosing be- tween them is a personal preference and an ongoing point of discussion in ophthalmic surgery. Corneal or scleral "We start surgery with an incision, use it during the entire surgery, and end with it. We also make sure to check it in the postop period," Dr. Muftuoglu said. "Scleral incisions are astigmatically more neutral. These wounds rarely leak because the tissue bed is vascularized and more elastic. Larger incisions are possible for rock hard cataracts and rigid IOLs. On the other hand, they are associated with conjunctival trauma, and you sometimes need to use cautery or more instruments. You may also have early entry into the anterior chamber and exposure of the ciliary body. By contrast, clear corneal incisions (CCI) allow you to avoid conjunctival trauma and cau- tery. They involve fewer steps and instruments, so you can save some surgical time. You can do them under topical anesthesia and close them without sutures. Despite these benefits, many studies, including a systematic review, 1 suggest a greater risk of endophthalmitis coincident with the adoption of clear corneal incisions, with a significant in- crease after 2000." Overall, CCIs are preferred over scleral tunnels, but surgeons should be familiar with scleral tunnels for cases involving rigid lenses and extra hard cataracts that require larger incisions. Superior or temporal clear corneal incisions Dr. Muftuoglu thinks that how physicians perform clear corneal incisions matters greatly. "First, we need to remember that the cornea is oval, not round, so if you have a superior incision, you will be closer to the center of the eye (around 5.5 mm) compared to a temporal inci- sion (around 6 mm)," he explained. "With a superior incision, the lid protects the wound, which may be an advantage for eye rubbers. The brow supports the surgeon's hands. On the other hand, you will be closer to the center. You may have some difficulty with CCC and phaco with a long tunnel. You'd also have Wound burn because of long tunnel Source: Orkun Muftuoglu, MD

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