May 2018

CATARACT

YES connect
Ins and outs of iris prolapse


by Liz Hillman EyeWorld Senior Staff Writer






The top image shows iris prolapse via the incision during a miLOOP (Iantech, Reno, Nevada) case. The iris was reposited with OVD (middle image), and a subincisional iris retractor
(bottom image) was placed prior to inserting the phaco handpiece to prevent reprolapse.
Source: David F. Chang, MD

Iris prolapse during cataract surgery can be challenging to deal with for new and experienced surgeons alike. In this month’s “YES connect” column, Elizabeth Yeu, MD, David F. Chang, MD, and Leela Raju, MD, explain how to readily identify the risk factors for iris prolapse and share several intraoperative strategies for managing prolapse. The bulk of their advice, however, focuses on sound operative techniques that should be employed to help prevent prolapse.
Fundamentally, iris prolapse is related to one of three things: (1) the wound (location, length, and relative size); (2) inherent iris tissue integrity (influenced by floppy iris syndrome, pseudoexfoliation); and (3) pressure gradients within both the anterior and posterior chambers. Avoiding rapid changes in pressure is critical in preventing iris prolapse, which is why young surgeons should learn to go in and out of the eye with irrigation off. In spite of a well-executed technique, prolapse will occasionally happen, and our experts have eloquently outlined methods to reposit the iris, steps that every surgeon should master.

Zachary Zavodni, MD,
YES connect co-editor


How to prevent iris prolapse and what to do if it happens

Too often, people think of iris prolapse as synonymous with intraoperative floppy iris syndrome (IFIS), but iris prolapse is its own differential diagnosis, said Elizabeth Yeu, MD, assistant professor, Department of Ophthalmology, Eastern Virginia Medical School, Norfolk, Virginia.
“When we think of iris prolapse, there are certain risk factors that make someone predisposed,” Dr. Yeu said.
IFIS is arguably the biggest risk factor for iris prolapse. David F. Chang, MD, clinical professor, University of California, San Francisco, and co-chair of the ASCRS Foundation, said that in addition to a history of systemic alpha antagonist medications, prior use of these drugs can also cause IFIS and may not be mentioned by patients. Leela Raju, MD, clinical associate professor, Department of Ophthalmology, New York University Langone Health, New York, said she will also look for iris atrophy in the other eye, if it has had surgery, which could suggest the potential for floppy iris. She said the preoperative signs of pseudoexfoliation, such as deposits on the lens or a “moth-eaten” edge of the pupil sphincter, which could suggest poor sphincter tone, or poor dilation in the office, could be warning signs for iris issues intraoperatively.
There are also a few intraoperative situations that could create conditions for iris prolapse. Dr. Yeu said these include too much ophthalmic viscoelastic device (OVD) in the eye, too much pressure coming posteriorly, or too wide or too short incisions.
As soon as she starts a case, especially in shallow eyes (those 21 mm or smaller), Dr. Yeu presses down on the cornea to assess the pressure. After she creates her paracentesis, she watches how the iris behaves when she injects epinephrine and lidocaine. If the iris seems to flutter more, it could indicate a floppy iris. She also observes iris behavior when injecting viscoelastic. Most of the time, Dr. Yeu said, the iris isn’t doing much of anything, but if you notice it bouncing up and down or being drawn up to the paracentesis when you come out of the wound, you need to start considering the risk of iris prolapse.
Upon noticing any iris billowing, inject an intracameral alpha agonist, such as epinephrine or phenylephrine, Dr. Chang said. The latter is only available in the U.S. via compounding pharmacies. Dr. Raju has tried atropine preoperatively to improve dilation and minimize floppiness with some success. If the pupil does not dilate well, Dr. Raju has a lower threshold for using a Malyugin ring or iris hooks, but she acknowledged that in some cases the iris is too floppy for a ring and hooks can be better. For patients taking systemic alpha blockers, there is a direct correlation between preoperative pupil diameter and IFIS severity,1 according to Dr. Chang.
“So if the pupil dilates poorly, one should consider mechanical dilation with a pupil expansion ring or with iris retractors,” he said.
From a fluidics standpoint, Dr. Raju said reducing all settings to avoid turbulence can prevent billowing of the iris as well. Dr. Yeu described this as having lower flow and continuous irrigation.
Iris prolapse will generally occur before phacoemulsification, Dr. Yeu said, but poor wound control or a short wound, sudden decompression of the chamber, or misdirection of aqueous due to anterior rotation of the ciliary body could cause the iris to come out at any point.
“When you have iris prolapse, your mind has to go through a few things,” Dr. Yeu said. First, check the pressure of the eye. If the eye is hard, it could be because you’ve used too much viscoelastic. Try reducing the amount of viscoelastic in the eye and see if you could sweep the iris back in. Dr. Yeu warned against using viscoelastic to shove the iris back through the same wound.
“That could make the entire situation worse,” Dr. Yeu said. “First, decompress the chamber, release some viscoelastic, and come around through another entry wound, either a paracentesis or a newly created paracentesis, to sweep the iris in and only use a dispersive viscoelastic on top to gently reposit and keep the iris back while you are entering your temporal wound again.”
If the eye remains firm despite your release of viscoelastic, Dr. Yeu said it could be something from the posterior segment causing more positive pressure. This could include anterior rotation of the ciliary body or a retrobulbar block. If it’s not from these sources and you know the pressure is coming posteriorly, Dr. Yeu said you need to alleviate vitreous pressure either through a vitreous tap or limited pars plana vitrectomy.
Dr. Chang said with mild IFIS, and if the eye hasn’t been overfilled with OVD, he is usually able to reposit incisional iris prolapse with small aliquots of OVD or with gentle instrument manipulation.
“These maneuvers can either be performed through the phaco incision for partial prolapse or more effectively through a sideport paracentesis,” he said. “The latter avoids gaping the incision and allowing more fluid egress and iris prolapse to occur. Sweeping the iris out of the incision and back into the anterior chamber is classically performed with a cyclodialysis spatula through a sideport paracentesis.”
If you already know your iris has a tendency to come out, make sure you keep the chamber maintained, putting in a little viscoelastic when you exit the wound, Dr. Yeu added.
“The potential for iris prolapse is not uncommon given the increasing use of BPH medications and the growing aging population,” Dr. Yeu said. “If it does happen because you have a poor wound, a short wound, or a wide wound, the iris might continue to come out. If that’s the case, it’s a better scenario to close the wound up, go to another area, and create a better wound so you can have a safe surgery.”
If incisional iris prolapse occurs early in the case, Dr. Chang advised using a subincisional iris retractor to prevent prolapse from recurring during phaco, irrigation/aspiration, or IOL insertion.
“Make a tiny stab incision just posterior to the clear corneal incision and aim toward the pupil margin,” Dr. Chang said. “The subincisional iris retractor will then occupy a different incision from the phaco and I/A handpieces. In addition to preventing incisional iris prolapse, an iris retractor through this paracentesis will pull the iris peripherally and posteriorly, so that it is not in contact with or being further traumatized by the phaco or I/A handpiece.”
Dr. Raju’s final piece of advice was to “always err on the side of using help for dilation in earlier cases,” either with rings or hooks.
“As you’re learning phaco techniques, it’s hard enough without having to deal with a constricting pupil; try to make it as easy on yourself as possible,” she said. “The extra time to put in the ring or hooks will be worth it in the end. Replace viscoelastic frequently.”
Dr. Chang emphasized that one should try to diagnose and address the cause of iris prolapse.
“Don’t just continue phaco or I/A alongside the prolapsed iris because once the iris stroma becomes damaged or frayed, it will become progressively harder to keep the iris from repeated prolapse,” he explained.

Reference

1. Chang DF, et al. Prospective masked comparison of intraoperative floppy iris syndrome severity with tamsulosin versus alfuzosin. Ophthalmology. 2014;121:829–34.

Editors’ note: Dr. Yeu, Dr. Chang, and Dr. Raju have no financial interests related to their comments.

Contact information

Chang
: dceye@earthlink.net
Raju: Leela.Raju@nyumc.org
Yeu: eyeulin@gmail.com

Ins and outs of iris prolapse Ins and outs of iris prolapse
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