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BLOG: Stop touching that iris
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In this issue of Ocular Surgery News, our cover story focuses on iridoplasty — a procedure that surgically induced damage to the iris sphincter often necessitates. And what’s the most common surgical cause of damage to the iris? Cataract surgery, which also happens to be the most common surgical procedure performed in the United States, bar none, with almost 4 million procedures performed each year.
An ideal surgical procedure should be quick and painless and cause minimal distortion of anatomy. Touching the iris during cataract surgery causes pain, inflammation and iris deformity that can be both cosmetically and optically problematic. It also leads to further iris constriction, which makes surgery longer and more challenging and increases the risk of further iris damage. In other words, touching the iris makes cataract surgery a less ideal procedure.
Iris retractors and pupil-expanding devices are also part of the problem. In normal, uncomplicated cataract surgery, the patient’s pupil, measured a month or so after the procedure, shrinks slightly compared with its preoperative size. After the use of pupil-expanding devices, most pupils are larger and more irregular, prompting questions from patients and a shallower depth of field, which makes a satisfactory refractive outcome more challenging. Adding epinephrine or a combination of epinephrine/lidocaine to the infusion bottle helps greatly, but we have found an even greater reduction in the need for pupil-expanding devices by using the combination of phenylephrine and ketorolac in the infusion bottle. This powerful combination, now FDA approved and marketed as Omidria (Omeros), maintains pupil dilation far better than epinephrine, especially in challenging cases. Eric Donnenfeld recently published a study showing a nearly 50% reduction in the use of pupil-expanding devices with phenylephrine/ketorolac compared with epinephrine alone.
It’s clear that pharmacologic control of the pupil diameter is far more physiologic than mechanical methods, and I hope we will see more tools in this category to help keep cataract surgery gentle. To be sure, little good can come from unnecessarily touching that iris.
Disclosure: Hovanesian reports he is a consultant for Omeros.