Background: Technical innovations in corneal transplantation have now made it possible to replace only the diseased part of the cornea, rather than the entire cornea as in penetrating keratoplasty (PKP). Patients with endothelial insufficiency due to Fuchs endothelial dystrophy, bullous keratopathy, or endothelial failure after keratoplasty can be treated with the new methods of posterior lamellar corneal transplantation: Descemet stripping automated endothelial keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK). It remains unclear which of these methods is better in the individual case.
Methods: We review the pertinent literature retrieved by a selective search in Medline and the Cochrane Library employing the terms "DMEK," "DSAEK," "DSEK," and "posterior lamellar keratoplasty." The publications considered in this article are those that contain important clinical information on the operative techniques.
Results: No randomized controlled trials of these techniques have been published to date. Numerous case series have shown that patients who undergo DSAEK (postoperative visual acuity ≥0.5 in 38-100%), and especially those who undergo it in early or intermediate stages of endothelial insufficiency, achieve a better functional result more rapidly than patients treated with PKP (postoperative visual acuity ≥0.5 in 47-61%). Only 23-47% of DSAEK patients achieve a visual acuity of 0.8 or more, compared to 36-79% of DMEK patients. Moreover, transplant rejection is seen in only 1-3% of cases of DMEK, compared to 0-8% after DSAEK and 1-23% after PKP.
Conclusion: Numerous case series show clear advantages of DMEK over DSAEK, which, in turn, has better results than PKP. Nonetheless, randomized controlled trials are needed to determine which operative method is best in each stage of corneal disease.