Eyeworld Daily News

42 | EYEWORLD DAILY NEWS | MAY 17, 2020 DAILY NEWS ASCRS VIRTUAL ANNUAL MEETING Iris prosthesis implantation the sutures, Dr. Snyder pres- surized the globe and put just enough tension at each of the locations to keep the pupillary aperture in the device well cen- tered. He starts with a double throw, then a single throw on top. Once you've fine-tuned the positioning with the proper tensioning, put in multiple locking throws, he said. "Per- sonally, I like to use a total of at least five throws, sometimes six or seven," Dr. Snyder said. Once you have your su- tures tied, trim the ends, and Dr. Snyder likes to leave the ends with a roughly 0.5–mm tag. Tuck the knots internally. The Gore-Tex suture may be a little slippery, he added. The device can be adjusted along the suture track to fine- tune the centration maximally. Once you're satisfied with the centration and the fixation, you can close the conjunctiva and Tenon's fascia with an absorb- able suture to ensure that the sutures are well covered from the long haul. Editors' note: Dr. Snyder has finan- cial interests with HumanOptics. There are two horizontal mattress sutures, he added, so you have to account for all four arms of the sutures. Sometimes one arm can be hidden under- neath. Dr. Snyder said to deepen the chamber with additional OVD and use two instruments to manually open the device fully. Then, two openings are created in the scleral wall at the level of the ciliary sulcus at each point of fixation. Dr. Snyder said it's im- portant to keep the opening roughly 3–4 mm apart, and line up each of the sutures with each opening. Microforceps are placed through the eye wall, and the device is pushed back enough so the microforceps can be placed in front of the device. Once you see the tip of the forceps, grasp the appro- priate suture, which will pass in from the temporal wound, and retrieve that suture from the scleral wall, doing this sequentially for each of the four sutures. Dr. Snyder added that 25-gauge instrumentation is easiest for this, but 23-gauge could work as well. It's important to make sure there are no overlaps with any of the sutures. Prior to tying After the lens was placed, the custom iris prosthesis was prepared by trephination, based on the size of the ciliary sulcus from direct measure. After trephination, he said to discard the peripheral outer portion and use the center portion. The artificial iris device is required to be fixated with su- tures. Dr. Snyder placed a CV8 Gore-Tex suture, approximately a 1.5-mm run, 1.5 mm in from the edge with two horizontal mattress bites. "We want to make sure to leave all four ends of the suture relatively long, so they're at least 2–2.5 cm in length. This will allow easier fixation later," he said. The central loop that con- nects the two sutures is then lysed, and the device folded in a trifold fashion, with the colored side outward. The device is tucked into a barrel of a Silver Series in- jection cartridge (Johnson & Johnson Vision), making sure not to overlap the different ends of the suture device. Each of the four pieces of the suture are placed through the barrel of the cartridge, making sure that it does not get trapped as the end of the cartridge is folded closed. The device is injected into the an- terior chamber, taking care to avoid any endothelial contact. The device will unfold spontaneously as it's injected into the anterior chamber, Dr. Snyder said, but he likes to use alternate instrumentation to prevent any inadvertent contact with the endothelium. Once the device is in position, be sure to manually remove the sutures from the barrel of the injector device so that they don't get caught. He stressed the importance of taking care not to overlap the sutures or get them twisted. by Ellen Stodola Editorial Co-Director D uring a virtual skills transfer lab on iris prosthesis, Michael Snyder, MD, Cincinna- ti, Ohio, shared a case presen- tation of a traumatically an- iridic, aphakic eye and detailed how to implant an artificial iris device. In this case, there was a small bit of vitreous prolapse through an opening in an oth- erwise intact posterior capsule, he said. The small, central opening was first cleaned by removing vitreous gel, using anterior infusion and a pars plana cannula to create an anterior to posterior pressure gradient. Vitreous gel was aspirated by vitrector device, and the vit- rector was used to enlarge the posterior capsular opening as evenly as possible into an ap- proximately 4.5-mm opening. From a nasal aspect, there was some fibrosis over the posterior capsule, which is OK, he said. He then filled the anterior chamber with a mixed cohe- sive and dispersive viscoelastic agent. Some of the anterior synechiae were gently dissect- ed using a 25-gauge needle. Occasionally, you can see some blood vessels in this type of fibrous ingrowth, he added. Once you create a full, open ciliary sulcus plane, sometimes with sharp dissec- tion or with scissors dissection, you will be ready to place an implant and ultimately, the artificial iris device, he said. Dr. Snyder measured the capsular opening to make sure the size was correct, and a 6-mm optic, three-piece pos- terior chamber implant was placed first into the ciliary sulcus. The iris prosthesis device at the end of Dr. Snyder's finished case Source: Michael Snyder, MD, screenshot from presentation

• Cover