EyeWorld Asia-Pacific December 2017 Issue

66 EWAP DEVICES December 2017 by Michelle Stephenson EyeWorld Contributing Writer Update on pupil dilating devices Both devices and pharmacologic agents should be in a physician’s armamentarium P erforming cataract surgery in patients with small pupils can be a challenge even for the most experienced surgeon, and in- adequate pupil dilation can cause a multitude of problems. Pupil dilation can be achieved by using devices or pharmacologic agents. Devices There are several pupil expansion devices on the market that deserve a look. “The ease of access and im- proved cost affordability of pupil expansion devices have allowed us to use them more frequently rather than resorting to the traditional iris hooks,” said Ken Kenyon, MD, Boston. “Certainly, it is inappropriate to do anything in the way of stretching the iris, as was suggested in the past, because of the potential for iris sphincter tears.” According to Dr. Kenyon, the remaining indications for iris hooks are for situations in which the pupil is extremely small and needs to be opened up incremen- tally or the pupil needs to be opened to a specific size. “If the iris is small and imperfect, you can’t presume that it will dilate to 7 mm without tearing. For all else, pupil re-expanders have largely supplanted the area where pupil expansion is required. I would also point out that especially in teaching capacities I think that the rings are more readily adapted by beginning surgeons and take less time to insert and retract than four or five iris hooks,” he said. Dr. Kenyon prefers the I-Ring (Beaver Visitec, Waltham, Mas- sachusetts). “It’s a soft, polyure- thane material that is gentle on the iris tissue. It is designed so that it can’t possibly squeeze and hence tear the iris. Thus, I have found it to be not only useful in my own surgery, but in teach- ing. Beginning surgeons adapt to it more easily than any other device,” he said. Boris Malyugin, MD, Moscow, Russia, prefers the Malyugin Ring (MicroSurgical Technology, MST, Redmond, Washington). “In some patients, the pupil is extremely small and possibly fibrotic, so it’s a good idea to use a pupil stretch- ing maneuver to expand it a little bit. With that maneuver, you cre- ate the space in which the pupil expansion ring goes. This will help to insert the pupil expansion device much more easily. Howev- er, pupil stretching is not recom- mended for intraoperative floppy iris syndrome. If the pupil size exceeds 3.5–4.0 mm and the iris is not fibrotic, it is mostly unneces- sary. I personally see no room for iris hooks in my practice. The only hooks I accept are the capsular hooks that help me stabilize the capsular bag and sometimes main- tain mydriasis. These are patients with ectopic lenses and fragile zonules,” he said. In cases where a stronger device is needed, Alan Crandall, MD, Salt Lake City, recommended the APX Ophthalmology Pupil Expanding Device (Haifa, Israel). “This provides quite a wide open- ing, but it can also be positioned in a location so that you have free access to your main incision, which is helpful,” Dr. Crandall said. He also uses Grieshaber Flex- ible Iris Retractors (Alcon, Fort Worth, Texas) and MST capsular hooks. “Both are quite nice. The difference is that the Grieshaber hooks are a little bit flatter and hold the iris slightly differently. The MST hooks have a large sur- face area, but it’s a little harder to get them out as far as you want. I try to figure out what kind of iris the patient has, and what kind of visualization I need,” Dr. Crandall said. “If you’re visualizing to do the cataract, that’s one thing. If you’re visualizing to do the scleral fixation, that’s a different thing. If you’re retrieving the lens from one part of the eye, I find that iris hooks are more appropriate in that setting. What I suggest is that you have an arsenal of these devices. You’re not going to be using them very often, but it’s really nice to be able to fine-tune whatever you need to each individual case. Some irises are flimsy and tear apart easily; in that case, you might want to use a thicker de- vice, such as the Malyugin Ring.” Pharmacologic agents Some surgeons use pharmacologic agents to dilate patients’ pupils. Dr. Crandall said he uses them in all cases. “I use 1% lidocaine with epinephrine, non-preserved, which dilates the pupil. I like to do that because it gives me an idea of the floppiness of the iris, and it also works very quickly. I use that to start 100% of my cases,” he said. Omidria (phenylephrine and ketorolac, Omeros, Seattle) is gain- ing popularity. It is added to the irrigating solution prior to surgery. IFIS cases For patients with intraoperative floppy iris syndrome (IFIS), Dr. Kenyon said that no preoperative strategy has been found to work. “I find that the best solution is a mechanical one, so I choose rings and hooks very readily. I don’t think that Omidria has any ap- plication in patients with IFIS. It’s not only the pupillary dilation, it’s the consistency of the pupil- lary tissue, which becomes very trampoline-like. It needs mechani- cal support, as the rings tend to afford very definitively,” he said. Dr. Malyugin said that IFIS can sometimes be anticipated. “Studies have shown that patients whose pupils are less than 7.0 mm have an increased chance of having IFIS. Their chance is four times greater than the patient with regularly well-dilated pupils. With IFIS, I think that injecting phenylephrine or epinephrine intracamerally is very helpful because it both strengthens the iris muscle and dilates the pupil. In IFIS, I do not rely solely on