Endothelial keratoplasty is continuing to evolve with the development of techniques that are moving toward more exact tissue replacement and providing better outcomes.
Indianapolis-Endothelial keratoplasty (EK) is continuing to evolve with the development of techniques that are moving toward more exact tissue replacement and providing better outcomes, according to Francis W. Price Jr., MD.
"Now is the time for surgeons who perform corneal graft surgery but only penetrating keratoplasty (PK) to seek training so they can learn EK and how to do it correctly," he added.
"Over the past few years, the number of graft procedures has been increasing, and I believe that is primarily because with the availability of EK, patients are having transplant surgery sooner and wanting their second eye done as well," he said.
Currently, Descemet stripping endothelial keratoplasty (DSEK)/Descemet stripping automated endothelial keratoplasty (DSAEK) is the predominant form of EK surgery. Six years of experience with DSEK/DSAEK show that it is more refractive-neutral, associated with faster visual recovery, and allows a tectonically stronger eye intra- and postoperatively than PK.
"With DSEK and DSAEK, we do not lose any eyes because of suprachoroidal hemorrhage from intraoperative or postoperative trauma, and that is one of the biggest reasons why I favor these EK procedures over PK," he said.
Over the longer term, the rate of endothelial cell loss after DSEK/DSAEK is at least as good as if not better than after PK. Results of one study including 5 years of follow-up showed much greater cell loss during the initial 6 months after DSEK compared with PK, which can be attributed to the increased surgical manipulation for DSEK graft placement. However, the rate of decline slowed thereafter so that compared with PK, endothelial cell loss was similar at 3 years and may be less at 5 years.
DSEK/DSAEK is relatively refractive-neutral and a dramatic improvement over PK in that regard, he said. However, astigmatism can occur because DSEK involves a 5-mm incision, and hyperopic shifts are possible as well when transplanting stroma.
Final VA represents a major drawback of DSEK, because most eyes achieve VA in the range of 20/30 to 20/40 versus 20/20. There are several features of DSEK that can account for these results. One of the most important is macro- or microfolds that can develop in the tissue when the relative curvatures of donor and host do not match up.
"The thicker the stroma, the more the folding, but even microfolds can limit vision. In a poster presented at [refractive subspecialty day at the 2009 annual meeting of the American Academy of Ophthalmology], we report a 2.5% incidence of repeat surgery for vision results that were unsatisfactory relative to patient or surgeon expectations," Dr. Price said.