Corneal transplantation: Beyond the horizon

Table 1 Comparison between ultra thin-Descemet's stripping automated endothelial keratoplasty and Descemet membrane endothelial keratoplasty

	UT-DSAEK	DMEK
Corneal layers involved	A double microkeratome pass to achieve a thin layer of donor central posterior stroma with the Descemet membrane and endothelium attached	Donor Descemet membrane and endothelium only
Thickness	< 130 µm	14-20 µm
preparation by eyebanks	Widely available from eyebanks	Mostly prepared intraoperatively by surgeons, provided by a limited number of eyebanks
Donor selection	Same criteria as DSAEK, less stringent	Preferably in older donors, as grafts from younger donors are more difficult to harvest and unroll
Recipient selection	Same criteria as DSAEK, less stringent	Less suitable in recipient with a shallow anterior chamber or complicated anatomy
Technical challenges	Similar technique compared with DSAEK	Donor preparation, insertion and manipulation of graft present a learning curve
Operative time	Shorter	Longer
BCVA	Similar percentage of eyes achieving 20/20 at 1 yr, but DMEK allows faster visual recovery with a higher percentage at 6 mo
Endothelial cell loss at 1 yr	Similar with around 35%
Tissue loss	2.8%	4.2%
Primary failure	1.4%	8.1%
Rejection probability at 1 yr	2.44%	1%
Rejection rate at 1 yr	2.8%	5.7%
Graft dislocation (partial)	3.9%	9%-92%
Rebubbling rate	3.9%	3%-17%

UT-DSAEK: Ultra thin-Descemet's stripping automated endothelial keratoplasty; DMEK: Descemet membrane endothelial keratoplasty; DSAEK: Descemet stripping automated endothelial keratoplasty; BCVA: Best corrected visual acuity.