EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
Issue link: https://digital.eyeworld.org/i/78788
August 2012 EW NEWS & OPINION 17 Figure 1. Measuring of the corneal graft size after marking of the cone using a marking pen to ensure that the entire cone will be resected Figure 6. Note the peripheral small air bubbles confirming that Descemet's membrane is pushed back into the anterior chamber by the big bubble. A crescent blade is used to dissect the anterior stroma that the DM edge shrinks and the anterior chamber's peripheral bub- bles coalesce into the center (Figure 7). Viscoelastic is then injected through the "nick" to push the DM posteriorly. The air bubbles should visibly move again to the periphery. Radial cuts with blunt Vannas or Fogla DALK scissors (Bausch + Lomb, Storz, Rochester, N.Y.) into the re- maining posterior layer of stroma allow the wedges to be removed. A peripheral skirt of posterior stroma does not cause any problems and is not noticeable once the stromal edema settles down in the post-op period. It is important to rinse off all the viscoelastic, which can lead to problems with DM adherence to the graft. 5. Preparing and securing the Figure 2 Figure 7 Figure 3 Figure 8 Figure 4 Figure 9 donor tissue: The donor tissue en- dothelium may be stained with vi- sion blue or the marking pen. This aids in the removal of the donor DM using dry wecks. When securing the donor tissue, it is important that deep bites on the host side are taken to ensure good apposition of the graft-host junction (Figure 9). Take care not to puncture the host DM in the periphery. Once all the sutures are in place, an air bubble may be left in the anterior chamber to tam- ponade the DM detachment and to prevent a double anterior chamber (Figure 10). If it is only a small area, this can be observed. However if the area is large, a rebubble procedure may be needed. The anterior cham- ber can be filled completely with air and the patient left supine for 10 minutes or more. The air bubble can then be titrated to cover the diame- ter of the graft for the patient to be discharged with instructions to con- tinue remaining supine until the bubble resolves. While the learning curve for DALK may be quiet steep initially, it is a rewarding procedure when suc- cessful. Conversion to PK is straight- forward should a macroperforation of the DM be unsalvageable. In pa- tients with corneal disease who have normal endothelium, this procedure must be considered. EW Figure 5 Figure 10 Source (all): Clara C. Chan, M.D. References 1. Reinhart WJ, Musch DC, Jacobs DS, et al. Deep anterior lamellar keratoplasty as an al- ternative to penetrating keratoplasty a report by the American Academy of Ophthalmology. continued on page 18