donor tissue was obtained from a 58-year - old donor male deceased after sudden cardiac arrest , who underwent rk many years before his demise . after consulting the surgeon , the corneas were preserved in organ culture medium and were provided to our institution for the use into be used for endothelial keratoplasty . briefly , the donor cornea was mounted on an artificial anterior chamber of the altk system ( moria , antony , france ) . the central corneal thickness of the donor was measured using ultrasound pachymetry ( sp-3000 ; tomey gmbh ) to be 733 m in the first cornea and 743 m in the second cornea . after the first cut , the central corneal thickness was measured again ( 325 m in the first case and 317 m in the second one ) . at this stage , the rk incisions could still be seen in both corneas . after turning by 180 , the dovetail of the artificial anterior chamber , a second cut was performed in both corneas using a 130 m microkeratome head . at this point , faint radial marks could still be seen in the periphery of both corneal lamellae , as could be better visible after trypan blue stain . videos 1 and 2 illustrate the tissue preparation in the described cases . as a large optical zone of at least 6.5 mm was found to be free from any scarring in both cases , the tissue was further prepared and transplanted as per standard technique . the first recipient was a 40 year old with a failed penetrating keratoplasty ( pk ) graft . at the last follow - up visit ( 2.5 years postoperatively ) , visual acuity was 20/25 with a spectacle correction of + 2.5 sphere 4.5 cylinder at 50. endothelial cell density was 1715 cells / mm ( i.e. , a loss rate of 34% ) . anterior segment optical coherence tomography ( as - oct ) demonstrated a graft of regular shape with a central thickness of 88 m , and a thickness of 90 m , 91 m , 93 m and 90 m , 1500 m temporally , nasally inferiorly and superiorly from the center . the second recipient was a 62-year - old female with fuchs ' dystrophy and cataract . she underwent ut - dsaek combined with phacoemulsification and pciol insertion . at the last follow - up examination ( also 2.5 years postoperatively ) , visual acuity was 20/25 with a spectacle correction of + 2 sphere 1.75 cylinder at 30. endothelial cell density was 1170 cells / mm ( i.e. , a loss rate of 57% ) . the cornea and graft - recipient interface appeared clear . as - oct showed a regularly shaped graft with a central thickness of 87 m , and a thickness of 82 m temporally , 110 m nasally , 119 m inferiorly , and 112 m , 1500 m superiorly from the center . phillips et al . have reported the use of two post - rk grafts for dsaek as a part of a case series of dsaek utilizing corneas with various anterior stromal pathologies . their results compared well with a control group of matched regular donors . in a reply to this work , khalifa et al . prepared two post - rk grafts using a 350 m head obtaining residual stromal bed of 120 and 132 m . in this report , radial endothelial scars were found underlying radial stromal incisions and scanning electron microscopy demonstrated epithelial cell presence in the stromal interface of the rk incisions in both grafts . in our cases , incision lines could still be seen after the second cut , but they could not be identified postoperatively , and we doubt whether they had any effect on the patient 's quality of vision . while we had no means of excluding the presence of epithelial cells in the implanted graft , it has been reported before that epithelial cells may be implanted into up to a third of venting incisions commonly performed for the evacuation of interface fluid in dsaek . theoretically , as corneal radial incisions are at risk for traumatic dehiscence even years after surgery , post - rk donor tissue may split apart under the high pressure induced by microkeratome - assisted dissection and/or get entangled inside the microkeratome head . in addition , the blade might be driven into a false route by one of the radial incisions , thus creating a different and deeper plane of dissection . descemet 's membrane endothelial keratoplasty ( dmek ) and pre - descemet 's endothelial keratoplasty ( pdek ) are techniques in which the stroma is not used for transplantation . as the post - rk grafts have sustained the pressure of the microkeratome - assisted dissection , we believe that they would also sustain the mechanical stress caused by peeling descemet 's membrane in dmek , and the pneumatic dissection done in pdek . in the latter technique , the radial incisions can theoretically enable air to escape superficially during the dissection , making the procedure more challenging . post - rk grafts prepared using these techniques will probably be no different from usual grafts in terms of the optical quality of the interface and the risk of epithelial ingrowth . after preparation for ut - dsaek , tissue with preexisting post - rk incisions has a scar - free optical zone large enough to be used for transplantation . the use of double - pass ut - dsaek technique enables the removal of all but the very deep stroma adjacent descemet 's membrane , thus minimizing the possibility of leaving in place clinically significant residual rk scars at the edge of the optical zone . recently , introduced microkeratome systems for the dissection of single - cut ultrathin grafts , as well as techniques such as dmek , and pre - descemet 's membrane endothelial keratoplasty ( pdek ) may prove equally efficient for the dissection of tissue with anterior stromal scars .
this is a report of two cases in which tissue that had undergone radial keratotomy ( rk ) was utilized for double - pass ultrathin descemet stripping automated endothelial keratoplasty ( ut - dsaek ) . 
 postoperative slit - lamp examination , visual acuity , anterior segment optical coherence tomography , and 
 specular microscopy were available 30 months after surgery . 
 both corneas from a donor , who had undergone rk several years before his demise , and were otherwise suitable for endothelial keratoplasty were prepared for ut - dsaek using double - pass dissection using first a 300 mm microkeratome head and then a 130m microkeratome head ( altk system , moria , antony , france ) . 
 after the second cut , the tissue was punched to 9.0 mm and transplanted in two eyes with endothelial decompensation according to standard technique . as early as 3 months after surgery , both patients had 20/25 best - corrected visual acuity , which remained stable for the following 27 months . 
 postoperative endothelial cell loss was 34% and 57% at 2.5 years . in conclusion 
 , post - rk donor tissue can be used for ut - dsaek .