Eyeworld

EW CATARACT 74 April 2016 by Michelle Dalton EyeWorld Contributing Writer 2.4-mm incision, and inserts the expander at that point. "It's better to put the device in earlier rather than later because if you wait until the capsulorhexis, the hook can catch on the capsulorhexis and tear it," he said, adding the pre- ferred removal is after IOL implanta- tion but before OVD removal. When he does use a ring, it's typically the Malyugin. The dual siz- es (6.25 mm and 7 mm) offer some flexibility, Dr. Vold said. "It's a simple one-step thing. Iris hooks are more involved. With the Graether pupil expander and some others, larger incisions are needed than with the Malyugin ring," Dr. Vold said, adding the cost of the devices may be a factor in use. Dr. Devgan agreed in part, noting these pupil expansion devices are about $125 "and you're not reimbursed for it." Inserting these rings can involve "a lot" of manipulation of the iris, Dr. Devgan added. "These devices can end up causing damage to the iris," he said. "The iris is like a wet tissue. Once it's torn apart, you can't undo that, and it could result in a traumatic mydri- asis. The pupil will look strange for the rest of the patient's life, and it's especially noticeable in people with light eyes." Dr. Lewis said that because there is a Food and Drug Adminis- tration-approved, preservative-free compound, "we can dilate the pupil very safely." Dr. Devgan said Omidria "does make a difference. It prevents the miosis and promotes the mydriasis. You can start a case with a 4 mm pupil and end up with a 5.5 mm pupil—and that's a doubling of the pupil area." Dr. Lewis added devices involve manipulating the eye, and he thinks Omidria "is a lot safer." "That's my first step—use medi- cation to try to get the pupil dilated. If I can't get the pupil size I want, and there's posterior synechiae, the next step is to put in either a hook or a ring." Expansion devices Dr. Lewis "might stretch" the pupil with 1 or 2 Sinskey or Lester hooks in a minority of small pupil patients, but prefers rings for greater control. If patients are using or have used tamsulosin, Dr. Lewis likes having a Malyugin ring available to better control the iris, noting the pupil issue may also be long-term use of pilocarpine or underlying uveitis. When Dr. Vold is using a pupil expander, he fills the anterior chamber with OVD, makes a 1.8- or There are multiple devices— rings and hooks—that are equally useful, said Steven Vold, MD, founder and chief executive officer, Vold Vision, Fayetteville, Arkansas. "These all have a role in making complicated cases easier," he said. Dilation Pupil dilation can be achieved with a variety of solutions, includ- ing Omidria (phenylephrine and ketorolac injection, Omeros, Seattle) or by placing lidocaine under the iris. Uday Devgan, MD, in private practice, Beverly Hills, and chief of ophthalmology, Olive View-UCLA Medical Center, Los Angeles, uses a cannula to inject lidocaine or phenylephrine between the iris and the lens. "Then you can use what Robert Osher, MD, calls visco-mydriasis, which involves using a viscosurgical device (OVD) to help push the iris out of the way," he said. "Lastly, I'll make a rhexis under the iris without directly visualizing it." If there's a 4 mm pupil, but surgeons create a 5 mm rhexis, "you can prolapse a nucleus with hydrodissection out of the capsular bag, have the pupil hold the nucleus in place while you chop and emul- sify it, and then you're done," Dr. Devgan said. Whether it's dilating drops or expansion devices, ophthalmologists have multiple aids to ease complex surgery S mall pupils continue to present a challenge for cataract surgeons, and while some surgeons are confident in their abilities to operate through small pupils, others prefer to use dilation drops or expansion devices. Some expan- sion devices need larger incisions than others, some are flexible in the number that can be used, and still others are designed with rigidity or reusability in mind. The underlying issue is achiev- ing adequate visualization behind the pupil, said Richard Lewis, MD, in private practice, Sacramento, California. "One of the major causes of intraoperative complications during cataract surgery occurs because of poor visualization through the pupil," he said. For years, surgeons used preservative-free versions of epinephrine, but it is no longer manufactured. The second obstacle is that surgeons determined the use of tamsulosin could lead to floppy iris syndrome. Device focus Expanding the pupil This patient has a small pupil, posterior synechiae, and a shallow anterior chamber. Inserting a pupil expansion ring in this eye is very difficult due to the lack of room, Dr. Devgan said. A 25-g vitrector was used to remove a small amount of anterior vitreous, then the chamber was deepened and iris hooks placed to expand the pupil and expose the cataract. Source: Uday Devgan, MD

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