EyeWorld Asia-Pacific December 2017 Issue

by Liz Hillman EyeWorld Staff Writer The basics of small pupil management From mydriatics to pupil expanders, how and when to use them S mall pupils can pose a challenge to even experi- enced cataract surgeons, limiting visualization of various lens and cataract struc- tures. They are often associated with other conditions, such as synechiae, pseudoexfoliation, dia- betes, or narrow-angle glaucoma. Without adequate dilation, iris trauma or capsule tearing could occur. 1 Fortunately, there are a variety of pharmacological and mechanical techniques to safely and adequately dilate or expand the pupil. Mydriatics are often a first-line choice to dilate the pupil. Charles Weber, MD , The Eye Institute of Utah, Salt Lake City, said he uses an intracameral mydriatic—lido- caine with epinephrine—at the start of every case. David Cran- dall, MD , Henry Ford Health Sys- tem, Detroit, on the other hand, said he’ll use 1.5% phenylephrine only in cases where he thinks he’ll need extra dilation. Dr. Weber and Dr. Crandall said they don’t use a mydriatic agent with ketorolac, an anti- inflammatory agent. Omidria (Omeros, Seattle, Washington), a combination of ketorolac and phe- nylephrine, is designed to provide both pupil dilation and pain man- agement. Phase 3 clinical studies published in 2015 (approval from the U.S. Food and Drug Admin- istration was granted in 2014) reported that the combination was safe and effective at maintaining mydriasis and reducing postopera- tive pain. 2 If dilation is not enough with a mydriatic agent or if there are other conditions that might merit the need for further iris expansion and support, a pupil expansion device could be used. Dr. Cran- dall said he tries to identify any possible issues with pupil size that might merit a pupil expansion device preoperatively in the clinic to be as prepared for surgery as possible. “If I have a pupil that is mar- ginal in diameter, when I infuse lidocaine into the anterior cham- ber, I’ll aim the cannula at the iris. If it undulates significantly, then I am concerned about intra- operative floppy iris syndrome (IFIS), and will be more likely to use pupil expansion of some kind. If it undulates only in one area, you also have to be concerned about zonular issues in that area,” Dr. Crandall said. “If there are any other ocular issues that I am worried about, it will lower my threshold to use pupil expansion. For example, if it’s a dense lens or white lens, or a posterior polar lens, I’ll be more likely to use pupil expansion. This eliminates one of the variables that I need to worry about, so I can concentrate on other things.” Dr. Weber also said he’ll start thinking about using a pupil ex- pansion device if he sees evidence of floppy iris. “If a patient dilates poorly and has a history of alpha-blocker use, I’ll use a pupillary expanding device,” he said. “If they dilate well but demonstrate signs of IFIS, I usually will only change my phaco fluidics. If they dilate poorly due to coexisting pathol- ogy such as pseudoexfoliation, I might simply change my fluidics in anticipation that the pupil will have stable dilation throughout the case.” When first learning to place the rings, Dr. Crandall said it’s helpful to use a small amount of viscoelastic underneath the iris. This creates space between the iris and lens at each of the points where the loops of the ring will be. “The far loop is the easiest to engage with the iris. Once that is in place, as I’m injecting the lens, I’ll rotate the superior and inferior loops to catch the iris. I’ll use an Osher/ Malyugin Manipulator to place the subincisional loop,” he said. Dr. Weber also backed the trick of using a cohesive viscoe- lastic to create space in the nasal ciliary sulcus, tenting up the iris away from the anterior lens cap- sule. From there, he tries to engage the lateral ring scrolls first, but if he can’t, he’ll engage all of the re- maining scrolls after fully insert- ing the ring with a manipulator. When it comes to removal, Dr. Crandall said he disengages the far loop first, then unhooks the su- perior and inferior loops, pushing the whole ring away to disengage the subincisional loop. In the case of a oppy iris or a complex case with greater manipulation, Dr. Weber prefers using iris hooks over a ring. Source: Charles Weber, MD EWAP CATARACT/IOL December 2017 59 continued on page 60