Is DMEK the Right Corneal Transplant for you?
Descemet’s membrane endothelial keratoplasty, or DMEK, is the most advanced surgery for replacing the back surface of the cornea. DMEK exchanges the unhealthy endothelium and Descemet’s membrane of a host for a healthy endothelium and Descemet’s membrane of a donor. Unlike other types of transplants for an unhealthy endothelium (Descemet’s stripping endothelial keratoplasty (DSEK) or ultra-thin DSEK), DMEK is an anatomical replacement of the unhealthy tissue. In both DSEK and ultra-thin DSEK, a layer of stroma is transplanted along with the endothelium and Descemet’s membrane. This extra tissue makes the transplanted tissue a bit thicker and can make the surgery a bit easier to perform. However, every bit of extra tissue that is transplanted, can increase the risk of rejection, prolong the recovery time after surgery, and reduce the potential visual acuity. The idea behind ultra-thin DSEK was to improve on DSEK, by transplanting a thinner layer of stroma, which can yield better vision and reduced the risk of rejection. DMEK is a more advanced version of the same procedure, eradicating stroma from the transplanted tissue. This can give a better vision result, quicker recovery after surgery, and reduce the risk of graft rejection. DMEK seems like the ideal surgery for unhealthy endothelium.
It is intuitive to most people that you should only remove things that are not working and only replace them with things that will work. If there is no need to remove or add anything extra, why do it? In cornea surgery, if you remove an unhealthy endothelium and Descemet’s membrane, it makes perfect sense to perform a DMEK, and only replace it with healthy endothelium and Descemet’s membrane. This would be the ideal scenario. However, there are times when DSEK or ultra-thin DSEK may be the procedure of choice. That extra bit of stroma can come in very handy at times, particularly when the condition of the eye can make the surgery challenging. Certain circumstances can make it very difficult to get a good result with DMEK tissue. Some of these scenarios include eyes with prior complicated surgery or trauma, including anterior chamber intraocular lenses, glaucoma devices, or vitrectomy surgery. The very thin DMEK tissue has to be controlled with fluid currents during the operation. Some of these scenarios can interrupt the fluid currents and possibly cause damage to the DMEK tissue. The thicker DSEK tissue is less dependent of fluid currents during the operation and is easier to handle in these tricky circumstances.
It is really important to let Dr MacIntyre know about your complete eye history, including any past surgery or trauma. This can impact on the decision to perform a DMEK, DSEK, or ultra-thin DSEK. Many of these decisions can only be made on an individual basis and after a comprehensive eye evaluation.