EyeWorld India June 2015 Issue

Corneal lamellar surgical procedures June 2015 35 EWAP SECONDARY FEATURE membrane from the overlying tissue to help ensure no stromal tissue is left behind. Although some surgeons use blunt cannulas to create the big bubble, Dr. Anwar prefers a 27-G hypodermic disposable needle. If he fails to achieve the big bubble, Dr. Anwar falls back on a manual technique to complete the case by near full thickness resection using fluid and air stromal emphysema technique. Dr. Price urged keeping the needle close to Descemet’s membrane and close to the central cornea when injecting to create the big bubble. “Most of us now use a blunt needle to reduce the chance of perforating Descemet’s as you are advancing toward the center, especially in a thin cornea,” Dr. Price said. “These needles either have a hole that points down and the tip is blunt or is a beveled needle, but it is all blunt so you can advance it and inject air.” A key point is to begin injecting a small amount of air—1 cc—because too much expansion too quickly can break Descemet’s membrane. “When you are doing one of these big bubble preparations the bubble only goes out to 7–8 mm and very often there is an annulus there that stops it,” Dr. Price said. “If you keep pressing hard with air it will cause the bubble to actually break—you can hear the pop in the operating room. If you go too fast—especially if there are any scars to Descemet’s—you can get a split across Descemet’s. If it starts in the center, that is pretty hard to salvage.” Complications There are a variety of responses to unintentionally breaking through Descemet’s membrane. Even in cases of a bad break, a surgeon can cut Descemet’s all the way around and remove it, then sew in the graft and put the removed section similar to a DMEK graft underneath an anterior lamellar graft. Another approach is to fill the eye with air. Filling the anterior chamber with air requires an inferior iridotomy to prevent pupillary block, Dr. Price said. A 90% to 95% air fill that covers the area where the break is will allow it to heal. “The problem is if you have a break that sits at 6 o’clock, that can be a bit more problematic and hard to fix with an air bubble,” Dr. Price said. “But if the break is at 12 o’clock, you can put in half an air fill, dilate the pupil, and that air will cover the break and give the bed time to adhere to the back of the donor graft.” Another potential issue in DALK can arise with suture removal. Dr. Anwar said loosened sutures in the early postop period require immediate replacement. Otherwise he removes sutures selectively depending on the presence of astigmatism. “If the patient’s vision corrects satisfactorily with glasses I tend not to remove sutures early,” Dr. Anwar said. “I believe the graft should heal in that position for a longer period of time. Early removal can sometimes result in significant wound dehiscence.” EWAP Reference 1. Sogutlu Sari E. Penetrating kerato- plasty versus deep anterior lamel- lar keratoplasty. Br J Ophthalmol. 2012;96(8):1063–1067. Editors’ note: Drs. Price and Anwar have no financial interests related to their comments. Dr. John has financial interests with Bausch + Lomb (Bridgewater, NJ) and ASICO (Westmont, Ill.). Contact information Anwar: dranwar00@yahoo.com John: lasikcornea@gmail.com Price: francisprice@pricevisiongroup.net Corneal lamellar surgical pr cedures June 2015 MORIA S.A. 15, rue Georges Besse 92160 Antony FRANCE Phone: +33 (0) 1 46 74 46 74 - Fax: +33 (0) 1 46 74 46 70 moria@moria-int.com - www.moria-surgical.com Both systems can be used with disposable and reusable Moria artificial chamber Consistent reproducibility for thin lamellae Wide range of precalibrated large-cut single-use heads Automated Contact us to arrange a demo DSAEK courses available with Pr. TAN, Singapore Get registered o n www.moria-surgical.com