Editing Corneal transplantation (section)

====Endothelial keratoplasty====

Endothelial keratoplasty replaces the patient's endothelium with a transplanted disc of posterior stroma/Descemets/endothelium (DSEK) or Descemets/endothelium (DMEK).<ref>{{Cite journal|last1=Ang|first1=Marcus|last2=Wilkins|first2=Mark R.|last3=Mehta|first3=Jodhbir S.|last4=Tan|first4=Donald|date=1 January 2016|title=Descemet membrane endothelial keratoplasty|url=https://bjo.bmj.com/content/100/1/15|journal=British Journal of Ophthalmology|language=en|volume=100|issue=1|pages=15–21|doi=10.1136/bjophthalmol-2015-306837|issn=0007-1161|pmid=25990654|doi-access=free}}</ref>

This relatively new procedure has revolutionized treatment of disorders of the innermost layer of the cornea (endothelium). Unlike a full-thickness corneal transplant, the surgery can be performed with one or no sutures.  Patients may recover functional vision in days to weeks, as opposed to up to a year with full thickness transplants. However, an Australian study has shown that despite its benefits, the loss of endothelial cells that maintain transparency is much higher in DSEK compared to a full-thickness corneal transplant. The reason may be greater tissue manipulation during surgery, the study concluded.<ref>{{cite journal | pmc = 2959124 | pmid=20031230 | doi=10.1016/j.ophtha.2009.07.036 | volume=117 | issue=3 | title=Descemet's stripping automated endothelial keratoplasty outcomes compared with penetrating keratoplasty from the Cornea Donor Study |vauthors=Price MO, Gorovoy M, Benetz BA, Price FW, Menegay HJ, Debanne SM, Lass JH| journal=Ophthalmology | pages=438–44| year=2010 }}</ref>

During surgery the patient's corneal endothelium is removed and replaced with donor tissue.  With DSEK, the donor includes a thin layer of stroma, as well as endothelium, and is commonly 100–150&nbsp;μm thick. With DMEK, only the endothelium is transplanted. In the immediate postoperative period the donor tissue is held in position with an air bubble placed inside the eye (the anterior chamber).  The tissue self-adheres in a short period and the air is adsorbed into the surrounding tissues.

Complications include displacement of the donor tissue requiring repositioning ("refloating").  This is more common with DMEK than DSEK.  Folds in the donor tissue may reduce the quality of vision, requiring repair.  Rejection of the donor tissue may require repeating the procedure.  Gradual reduction in endothelial cell density over time can lead to loss of clarity and require repeating the procedure.

Patients with endothelial transplants frequently achieve best corrected vision in the 20/30 to 20/40 range, although some reach 20/20.  Optical irregularity at the graft/host interface may limit vision below 20/20.