EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
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the length should be between 2 and 2.5 mm. During wound construc- tion, the keratome is oriented along the corneal pane until a 2 to 2.5 mm valve is achieved, then the tip of the keratome is dipped toward the lens so that a two-plane incision is achieved with adequate corneal valve. An overly long tunnel is also not desirable as maneuvering the instruments and phaco probe will be a challenge. With a short tunnel, the risk of iris prolapse starts with hy- drodissection and can persist until the end of the case. More impor- tantly the iris becomes floppy and the iris prolapse persists through the rest of the procedure. To reduce the chance of iris prolapse, it helps to burp out some viscoelastic with a cannula, prior to hydrodissection, by pressing on the posterior lip of the wound. Also, following each round of hydrodissection, decom- pression of the nucleus in the bag will release capsular bag pressure and prevent forward bowing of the iris. The prolapsed iris can be reposited with a high molecular weight cohesive viscoelastic, which will help to hold the iris back as the phaco tip or subsequent instruments are introduced. The chamber should not be overfilled with viscoelastic or balanced salt solution. While intro- ducing the phaco and I/A probe the iris tends to rise toward the wound. To avoid this try to keep the probe along the floor of the tunnel rather than raising it, so as to retain the iris within the chamber. Alternatively a cyclodialysis spatula is introduced through the paracentesis and used to mechanically hold the iris back while the phaco tip is introduced. Intraoperative iris prolapse brings the pupil down and keeps interfer- ing with the procedure. Iris retrac- tors might help to expand the pupil during the surgery. One hook is introduced below the incision so that the iris plane is low and does not interfere with the procedure. In case of an excessively floppy iris, an iridectomy may be done. In some instances even after an iridec- tomy the edge of the cut iris may tend to prolapse through the wound so it might be better to trim the edges of the cut iris. Toward the end of the case the speculum is loosened, wound and side ports hydrated, and finally chamber formed. The ante- rior chamber should not be overly filled in these instances. Intracam- eral pilocarpine can be used at the end of the case to reduce the chance of postop iris incarceration or pro- lapse. I wound recommend that these wounds are always sutured to reduce the chance of postop wound leak, iris prolapse, and endoph- thalmitis. In the event of persistent iris prolapse during phaco or cortex aspiration, it might be better to abandon the wound and create a fresh tunnel at a different site after suturing the primary incision. www.woc2014.org facebook.com/WOC2014 twitter.com/WOC2014 ยช5$7# Register Today eg R o r T To e t is eg y ay d t f w ww w ww C2014 O m/W o .c r. e t tt i w tw C2014 O m/W o k.c o o b e ac fa c2014.o o .w w. C2014 C2014 rg c2014.o Figure 2: Iris prolapse occurs following hydrodissection. Source: Thomas Oetting, MD continued on page 86 84-90 Residents_EW February 2014-DL2_Layout 1 1/30/14 11:13 AM Page 85