AUG 2013

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

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August 2013 Figure 1. Main incision starts too anterior and goes too long Figure 2. Long incision results in significant corneal edema obscuring the view of the anterior chamber Source (all): Thomas Oetting, MD It is a common occurrence with resident cases to have issues with wound construction. In this situation, the incision is started too anteriorly in the cornea and the keratome is allowed to tunnel too far before the incision is completed through the endothelium. Here are my thoughts: 1. Salvaging the existing incision: This incision is recognized as problematic early in the case while performing the capsulorhexis. At this time, attempts to propagate the rhexis subincision- ally cause significant striae and poor view through the cornea because it is difficult to pivot instruments through a long and anterior incision. If this is recognized early on, one of my colleagues recommends modifying the incision. The keratome or supersharp can be used with a little diagonal force directed at both sidewalls of the incision along its inner lip to convert the corneal tunnel into a partial corneal free flap. Once the inner portion of the incision is converted to a free flap, the result is a shorter, more posteriorly positioned corneal tunnel that allows greater degrees of freedom for surgical instruments. 2. Abandoning the original incision: Early in the case, prior to excess manipulation, the original incision can be abandoned and a new one created adjacent to the first. This does not solve all the problems of the first incision. Namely, visualization through the long corneal tunnel can still be somewhat difficult, and the surgeon has to be comfortable operating with a different (usually wider) angle between incisions. Also, the new incision has to be created carefully so as not to intersect with the original incision or else communication between the two incisions will cause excess leakage of fluid and chamber instability. However, these issues aside, sometimes starting over again with a new incision will greatly facilitate the rest of the procedure. 3. Pushing forward with the original incision: Often there is considerable inertia to use a poorly constructed incision if the capsulorhexis can be completed successfully. However, hydration of the incision, which eventually leads to hydration of the surrounding corneal stroma, will lead to impaired visibility. Once corneal edema occurs, there is really nothing that can be done intraoperatively to improve visibility. So if the original incision is to be used, it is important to take a couple of extra steps to prevent/ minimize corneal hydration. First is to shorten the phaco tip. Keeping the phaco tip short and positioned centrally in the anterior chamber will ensure the irrigation ports on the sleeve stay within the anterior chamber and away from the cornea. During nuclear fragmentation and removal, it is EW RESIDENTS 51 important to make a conscious effort to keep the phaco tip away from the incision because the default for many trainees is to withdraw the instrument away from the capsule or inattention to the position of the phaco tip while maneuvering the side-port instrument. Second is to remove subincisional cortex first during irrigation/aspiration. Corneal hydration will likely worsen during cortical removal, so it is important to prioritize the subincisional segments, which are often the most difficult and time consuming, as early as possible while visibility is still somewhat preserved. 4. Preventing the long or anterior corneal incision: The best strategy is to learn how to avoid making this mistake altogether. For surgeons who use a two-step technique to create a partialdepth vertical groove before constructing the corneal tunnel, the ideal starting point is almost limbal—as far peripheral as possible without disturbing conjunctiva. For surgeons who do not make a separate vertical groove, the point of entry of the keratome should be slightly more anterior, often within the arcus senilis. The length of the corneal tunnel should be approximately 1/3 the total length of the blade tip. Some keratomes are marked at this point, but with trial and error you may find that completing the incision before reaching this mark may lead to better tunnel dimensions. EW Editors' note: Drs. Chiu and Pruett have no financial interests related to this article. Dr. Sun has financial interests with Alcon (Fort Worth, Texas). Contact information Chiu: ChiuC@vision.ucsf.edu Pruett: paul.pruett@emory.edu Sun: grs2003@med.cornell.edu Find us on social media Are you a fan of EyeWorld? Like us on Facebook at facebook.com/EyeWorldMagazine

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