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Developed by US ophthalmologists, the surgical procedure DSAEK (Descemet's Stripping Automated Endothelial Keratoplasty) is increasingly being employed in German eye clinics too.
Developed by US ophthalmologists, the surgical procedure DSAEK (Descemet's Stripping Automated Endothelial Keratoplasty) is increasingly being employed in German eye clinics too. We transplant a layer of the cornea measuring only 100 to 200 micrometers in thickness, which consists of parts of the stromal layer and the endothelium. It is a thin layer of cells, which is inserted onto the back surface of the cornea separating the cornea from the fluid in the anterior chamber of the eye, explains Professor Dr med. Friedrich E. Kruse, Chairman of the Department of Ophthalmology, Friedrich-Alexander University of Erlangen- Nuremberg, Germany. The endothelial cell layer is harvested by means of an automated precision knife, the microkeratome, from the donor cornea. After the operating surgeon has removed the diseased endothelial layer from the recipient cornea, the fine lamella from the donor is inserted into the eye chamber through a small incision made next to the cornea. The surgeon places the lamella on the inner side of the cornea.
This new procedure is suitable for those patients who suffer from corneal clouding caused by diseased endothelium. That is the case for some 40%. The proportion of endothelium in the cornea is minimal. It is not therefore necessary the replace the entire cornea, says Kruse.
To ensure that the new endothelial layer sticks to the cornea, the surgeon injects an air bubble into the eye chamber after transplantation. To keep this in position, patients must remain lying on their backs in bed for two days. In total, the recovery phase, however, is notably shorter than that after a conventional corneal transplant, Kruse explains in the run-up to WOC 2010. It mostly takes 18 months before patients are able to see again properly. With DSAEK, however, it generally takes only several weeks to a few months.”
DMEK (Descemet's Membrane Endothelial Keratoplasty) is a further development of DSAEK. Here, the surgeon only grafts the Descemet's membrane and the endothelium, i.e. a ten micrometer thick layer. Results of the first 100 patients who underwent surgery with this procedure show that visual acuity is noticeably better than after DSAEK. However, this technique is more complicated, according to Kruse.
After a conventional transplant, there are often irregularities in the curvature of the cornea. This astigmatism leads to patients having to wear eyeglasses or contact lenses. With DSAEK or DMEK we have been able to minimize this problem markedly, reports Kruse. He and his colleagues will be discussing the current results of both operative procedures at WOC 2010.