DMEK: then and now

[caption id="attachment_8824" align="alignnone" width="203"] Lamis Baydoun MD[/caption]   The evolution of the Descemet’s membrane endothelial keratoplasty (DMEK) procedure since it was first introduced and performed by Gerrit Melles MD, PhD in 1998 and 2006, respectively, provides an illustration of how an initially very difficult technique for any surgeon can be transformed into an elegant technique that is safer and easier to learn and perform, said Lamis Baydoun MD, Netherlands Institute for Innovative Ocular Surgery, Rotterdam, The Netherlands. At a Cornea Day session at the 21st ESCRS Winter Meeting in Maastricht, The Netherlands, Dr Baydoun presented video clips of Dr Melles performing the procedure on the first DMEK patient in 2006 and contrasted it with another video clip showing the modern standardised iteration of the technique 10 years later. In his early DMEK procedures, Dr Melles first did a ‘half-depth’ limbal pre-incision of the main incision and used three side-ports for instrument insertion. Then he filled the anterior chamber with air, performed the descemetorhexis, the scoring and stripping of Descemet’s membrane in the same manner he had previously introduced for Descemet’s stripping endothelial keratoplasty (DSEK). He would then complete the incision and use a prototype balloon pipette – somewhat analogous to a miniature turkey baster in design – to inject the scrolled Descemet’s membrane into the anterior chamber. Dr Baydoun noted that the pneumatic design of the injector meant that it provided little control during the injection. Once the graft was inside the anterior chamber, Dr Melles would flush it through the main incision (i.e. from inside the eye) to unfold it. As soon as a flange of the graft was unfolded, this part was lifted on to the posterior stroma by injecting an air bubble underneath. In the current version of the procedure, Dr Melles and his associates do not perform a pre-incision, but only mark the incision at 12 o’clock. The following steps, i.e. creation of three side-ports and Descemetorhexis under air, have not changed. A main incision of 3.0mm x 3.0mm is then created to remove the detached tissue. The now developed injector, consisting of a curved glass pipette attached to a syringe, similar in design to injectors for foldable intraocular lenses, allows for a very smooth and well-controlled injection of the graft. A main difference to the early DMEK procedures is that nowadays graft manipulation is performed in a ‘no-touch’ (i.e. indirect) fashion using an air bubble as an intraocular tool to manoeuvre and unfold the graft, while applying gentle pressure with a cannula from on top of the cornea (i.e. outside the eye). As in the original procedure, they use an air bubble to lift the graft to the stroma, however this step is only fulfilled provided that the graft is completely or majorly unfolded. “You can see how difficult it was to perform DMEK in the early days, compared to today,” Dr Baydoun concluded. Lamis Baydoun: baydoun@niios.com; research@niios.com
 *To view a video of the first DMEK patient and surgery, go to: 
www.niios.com

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