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EW CATARACT 48 October 2016 by Liz Hillman EyeWorld Staff Writer hooks if the anterior chamber is shal- low, although she noted that just be- cause an eye is short does not mean it has a shallow chamber. She also uses a dispersive viscoelastic to maintain the space, refilling with it often, espe- cially when she removes instruments from the anterior chamber. For the very crowded chamber, digital massage or a vitreous tap might be in order. To start though, Dr. Raju said she gives intravenous acetazolamide or mannitol in an eye with an axial length of less than 21 mm. She would avoid retrobulbar anesthesia in favor of peribulbar or topical anesthesia, both of which she said could avoid surgeon-created posterior pressure. "If I still have shallowing after the viscoelastic is placed, I will con- sider a vitreous tap or dry vitrecto- my," she said. Dr. Zavodni said a "soft shell" technique with a cohesive OVD injected within a shell of dispersive OVD could increase chamber depth, but he cautioned against overinflat- ing, which could cause iris prolapse. Dr. Zavodni said he might also use preoperative IV mannitol to soften the globe and allow the anterior chamber to deepen. A pars plana vitreous tap is an option for extreme cases as well. "In performing a pars plana tap, I make my sclerotomy 3 mm posterior to the limbus and aim pos- teriorly to the optic nerve to avoid hitting the lens. I prefer the use of a vitrectomy cutter over a needle be exacerbated by phacomorphic narrowing in eyes with more ad- vanced cataracts," he said. "In eyes with notably narrow angles, I will perform gonioscopy prior to dilation to assess if the angle is occludable. I look closely for both anterior and posterior synechiae, as these are more common in hyperopic eyes with previous angle closure episodes and they are more likely to result in poor intraoperative dilation." Intraoperative situations Intraoperatively, there are many considerations for cataract surgery in short eyes. First, Dr. Raju said she makes sure that the speculum is not placed too wide as it could contribute to posterior pressure. Perhaps the most immediate consideration in these cases is the prevention of iris prolapse. "I try to make my incision lon- ger than average in these cases," Dr. Zavodni said. "I also have a very low threshold to place a Malyugin ring, as placement often helps to mini- mize iris prolapse. The rhexis can be more difficult to control because of ergonomic adjustments neces- sary to accommodate the crowded anterior chamber and because these lenses often have increased anterior capsule convexity, which will steer a rhexis tear peripherally." To prevent iris prolapse, Dr. Raju said she might create a scleral tunnel versus a clear corneal incision. She also said she'd consider using iris Preventing iris prolapse, increasing chamber depth, IOL calculations, and more W hen faced with cata- ract surgery in a short eye, one interesting piece of advice doesn't depend on surgical technique or skill: Just speak with your patient, recommended Leela Raju, MD, associate professor, De- partment of Ophthalmology, NYU Langone Medical Center, New York. "Reassuring patients throughout the procedure, or 'vocal local,' can help keep patients from holding their breath due to anxiety that could also increase posterior pres- sure," she said. Of course, there are many clini- cal and surgical things you can do to help manage these cases and achieve safe and targeted outcomes. Preoperative preparation During the preop examination, Dr. Raju tells patients there may be a need for additional medications in the surgery as well as the possibil- ity for more intraoperative proce- dures to make sure everything goes smoothly. "Prior discussion of possibilities can always help the patient feel more informed and comfortable. But we have to assure them we have a plan in place in case the surgery varies a little from the standard operation," Dr. Raju said. Zachary Zavodni, MD, The Eye Institute, Salt Lake City, said that patients with extremely short axial lengths (less than 20 mm) and small white-to-white measurements (less than 11 mm) may be at higher risk for suprachoroidal hemorrhage, which should be discussed. In addi- tion, even a maximum power IOL (i.e., 40 D) might not fully correct the refractive error. In these cases, Dr. Zavodni said he tells patients they may still need to wear glasses or perhaps consider a piggyback IOL in the future. During the exam, Dr. Zavodni said he looks closely at the extent of anterior segment crowding. "Short, hyperopic eyes tend to have narrow angles, which can Considerations for cataract surgery in short eyes S hort eyes present multiple challeng- es for the cataract surgeon. There is less working space, potentially resulting in more endothelial damage, and the iris is more prone to prolapse. These eyes often have synechiae as well as convex anterior capsules that may make the capsulorhexis run out. When the axial length is very short, there is also greater concern for posterior pressure and suprachoroidal hemorrhage. Even if the surgery goes perfectly, IOL selection formulas are less accurate, so patients should be counseled appropriately. One tip I learned from David Chang, MD, is to note the anterior chamber depth when I examine patients at the slit lamp. I have found that to be a useful observation to uti- lize as a fudge factor with third generation IOL formulas. This month, two experts, Leela Raju, MD, and Zachary Zavodni, MD, share valuable tips to tackle these difficult cases. Their pearls include preoperative consider- ations, counseling, patient positioning, and operative planning. Drs. Raju and Zavodni do a fantastic job walking us through the entire pre-, peri-, and intraoperative process. One final note: Doing a dry vitreous tap can be very helpful for achieving a deeper anterior chamber if viscoelastics are unable to create sufficient working space. However, a small amount of vitreous removal is often plenty. In very short eyes, the pars plana may not be where you expect, so you do not want to do a tap in that situation. Bryan Lee, MD, YES Connect co-editor YES Connect

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