Eyeworld

EW CATARACT 38 July 2014 by Tony Realini, MD, MPH Intraoperative pupil expansion: Making challenging cases easier P inpoint pupils, zonular weakness, small eyes— these and other features virtually guarantee a non- routine case. Some adren- aline junkies thrive on the most complicated, technically challenging cataract surgeries imaginable. Most surgeons, however, strive to make every case as routine as possible. This requires actively addressing the factors that can be controlled and minimizing what is left to chance. The dreaded small pupil Small pupils are a common occur- rence in a busy cataract practice. A poorly dilated pupil can set the tone for the entire procedure; without ad- equate visibility, every step is made more challenging than it needs to be. Fortunately, this is an issue that can be identified and planned for during the preoperative assessment, and there are several options avail- able for expanding the stubborn pupil. Simple viscodilation works for many eyes. Iris retraction hooks have been around for decades and are quite effective. More recently, the Malyugin ring (MicroSurgical Technologies, Redmond, Wash.) has become available. Each of these options has its advantages and disadvantages. "Poor pupil dilation has been shown to increase the risk of compli- cations during cataract surgery," said Jonathan Fay, MD, Albert Einstein College of Medicine, New York. Albert Khouri, MD, Rutgers University, Newark, N.J., agreed. "Complications associated with small pupils during cataract surgery include capsule rupture and vitreous loss," he said. "Pupil enlargement techniques such as iris retraction and pupil stretch techniques can fa- cilitate intraoperative visualization and prevent complications." The way we handle the small pupil can also cause problems. "Pupil manipulation during cataract surgery may lead to pigment disper- sion with subsequent inflammation and intraocular pressure (IOP) elevation," said Dr. Fay. Malyugin ring safety Dr. Fay recently conducted a retro- spective study to evaluate the course of postoperative inflammation and IOP control in eyes undergoing cataract surgery with and without the use of a Malyugin ring. He and his colleagues reviewed the medical records of 20 consecu- tive cases utilizing the Malyugin ring and compared the outcomes to a control group of 21 age- and gender-matched cases all performed by the same surgeon. On the first postoperative day, mean IOP was similar between groups, he said. "In the Malyugin ring group, there was one patient who experienced an IOP spike of 30 mmHg or more, compared to two patients with similar IOP spikes in the control group," he added. Uncorrected visual acuity was substantially lower on the first post- operative day in the Malyugin ring group compared to the controls. "The control group gained an average of 0.4 lines of Snellen acuity by the first day, compared with an average loss of 1.3 lines in the Malyugin ring group," he said. This is likely not attributable to the use of the ring but rather to the fact that it was necessary due to the small pupil. By one month postoperatively, both groups had comparable IOP and visual acuity outcomes, he said. Ring vs. hooks Dr. Khouri and his colleagues also conducted a retrospective analysis of small pupil cases. In their series, 20 eyes underwent pupil expansion using the Malyugin ring and another 20 received iris hooks. In the Malyugin ring group, visual rehabilitation was complete on the first postoperative day for the group as a whole. "This group's aver- age visual acuity on the first day was the same as their final visual acuity 18 months later," Dr. Khouri explained. In the hooks group, in contrast, visual recovery was delayed. "At postoperative day 1 and week 1, the average visual acuity in the hooks group was substantially below that of the ring group and did not reach its final equivalent until 1 month postoperatively," he said. Mean IOP was comparable in both groups at all time points, he added. This study was strengthened by the use of small pupil cases in both the active and control groups, making the results more directly attributable to the method of pupil expansion rather than the need for pupil expansion. Practical applications These studies help shine some light on the benefits of pupil expansion and the relative pros and cons of various pupil expansion tools. Im- portant issues include performance, in terms of visual recovery after surgery, and safety, in terms of complications such as elevated IOP. Both studies found no detrimen- tal effect of the Malyugin ring on visual recovery. "The speed of visual recovery was faster with the Malyu- gin ring than with the iris hooks in our study," Dr. Khouri pointed out. Likewise, both studies found no detrimental effect of the Malyugin ring on postoperative IOP. "The use of the Malyugin ring for pupil expansion during cataract surgery was not an independent risk factor for postoperative increased IOP," said Dr. Fay. He concluded, "The potential risks of the Malyugin ring are likely outweighed by the benefits of im- proved surgical exposure and re- duced likelihood of intraoperative complications." EW Editors' note: Drs. Fay and Khouri have no financial interests related to this article. Contact information Khouri: albertkhouri@hotmail.com Fay: jdfay84@gmail.com Mean difference of best corrected visual acuity at all time points for Malyugin ring (green) and iris hooks (blue) Source: Albert Khouri, MD 38-42 Cataract_EW July 2014-DL_Layout 1 6/30/14 8:43 AM Page 38

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